first commit

.editorconfig

+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+root = true
+
+[*]
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+indent_style = space
+indent_size = 2
+end_of_line = lf
+
+[*.md]
+trim_trailing_whitespace = true

.gitattributes

+*.rb diff=ruby
+*.gemspec diff=ruby
+

.gitignore

+# See https://help.github.com/articles/ignoring-files for more about ignoring files.
+#
+# If you find yourself ignoring temporary files generated by your text editor
+# or operating system, you probably want to add a global ignore instead:
+#   git config --global core.excludesfile '~/.gitignore_global'
+
+# Ignore bundler config.
+.bundle/
+
+# Ignore the default SQLite database.
+test/dummy/db/*.sqlite3
+test/dummy/db/*.sqlite3-journal
+
+# Ignore all logfiles and tempfiles.
+log/*.log
+!test/dummy/log/.keep
+!test/dummy/tmp/.keep
+test/dummy/log/*.log
+test/dummy/tmp/
+
+# Ignore uploaded files in development
+test/dummy/storage/*
+!test/dummy/storage/.keep
+
+pkg/
+.byebug_history
+
+node_modules/
+test/dummy/public/packs
+test/dummy/node_modules/
+yarn-error.log
+
+*.gem

.rubocop.yml

+inherit_gem:
+  rubocop-rails_config:
+    - config/rails.yml
+
+AllCops:
+  TargetRubyVersion: 2.4
+  Exclude:
+    - 'test/dummy/db/schema.rb'
+
+# frozen_string_literal: true
+Style/FrozenStringLiteralComment:
+  Enabled: true
+  EnforcedStyle: when_needed
+
+# Prefer &&/|| over and/or.
+Style/AndOr:
+  Enabled: true
+
+# Do not use braces for hash literals when they are the last argument of a
+# method call.
+Style/BracesAroundHashParameters:
+  Enabled: true
+
+# Align `when` with `case`.
+Layout/CaseIndentation:
+  Enabled: true
+
+# Align comments with method definitions.
+Layout/CommentIndentation:
+  Enabled: true
+
+# No extra empty lines.
+Layout/EmptyLines:
+  Enabled: true
+
+# In a regular class definition, no empty lines around the body.
+Layout/EmptyLinesAroundClassBody:
+  Enabled: true
+
+# In a regular method definition, no empty lines around the body.
+Layout/EmptyLinesAroundMethodBody:
+  Enabled: true
+
+# In a regular module definition, no empty lines around the body.
+Layout/EmptyLinesAroundModuleBody:
+  Enabled: true
+
+# Use Ruby >= 1.9 syntax for hashes. Prefer {a: :b} over { :a => :b }.
+Style/HashSyntax:
+  Enabled: true
+
+# Method definitions after `private` or `protected` isolated calls need one
+# extra level of indentation.
+Layout/IndentationConsistency:
+  Enabled: true
+  EnforcedStyle: normal
+
+# Two spaces, no tabs (for indentation).
+Layout/IndentationWidth:
+  Enabled: true
+
+Layout/SpaceAfterColon:
+  Enabled: true
+
+Layout/SpaceAfterComma:
+  Enabled: true
+
+Layout/SpaceAroundEqualsInParameterDefault:
+  Enabled: true
+
+Layout/SpaceAroundKeyword:
+  Enabled: true
+
+Layout/SpaceAroundOperators:
+  Enabled: true
+
+Layout/SpaceBeforeFirstArg:
+  Enabled: true
+
+# Defining a method with parameters needs parentheses.
+Style/MethodDefParentheses:
+  Enabled: true
+
+# Use `foo {}` not `foo{}`.
+Layout/SpaceBeforeBlockBraces:
+  Enabled: true
+
+# Use `foo { bar }` not `foo {bar}`.
+Layout/SpaceInsideBlockBraces:
+  Enabled: true
+
+# Use `{a: 1}` not `{ a:1 }`.
+Layout/SpaceInsideHashLiteralBraces:
+  Enabled: false
+
+Layout/SpaceInsideParens:
+  Enabled: true
+
+# Check quotes usage according to lint rule below.
+Style/StringLiterals:
+  Enabled: true
+  EnforcedStyle: double_quotes
+
+# Detect hard tabs, no hard tabs.
+Layout/Tab:
+  Enabled: true
+
+# Blank lines should not have any spaces.
+Layout/TrailingBlankLines:
+  Enabled: true
+
+# No trailing whitespace.
+Layout/TrailingWhitespace:
+  Enabled: true
+
+# Use quotes for string literals when they are enough.
+Style/UnneededPercentQ:
+  Enabled: true
+
+# Align `end` with the matching keyword or starting expression except for
+# assignments, where it should be aligned with the LHS.
+Layout/EndAlignment:
+  Enabled: true
+  EnforcedStyleAlignWith: variable
+
+# Use my_method(my_arg) not my_method( my_arg ) or my_method my_arg.
+Lint/RequireParentheses:
+  Enabled: true

.ruby-version

+ruby-2.5.1

Gemfile

+# frozen_string_literal: true
+
+source "https://rubygems.org"
+git_source(:github) { |repo| "https://github.com/#{repo}.git" }
+
+# Declare your gem's dependencies in workflow_core.gemspec.
+# Bundler will treat runtime dependencies like base dependencies, and
+# development dependencies will be added by default to the :development group.
+gemspec
+
+# Declare any dependencies that are still in development here instead of in
+# your gemspec. These might include edge Rails or gems from your path or
+# Git. Remember to move these dependencies to your gemspec before releasing
+# your gem to rubygems.org.
+
+# To use a debugger
+# gem 'byebug', group: [:development, :test]
+
+gem "sqlite3"
+
+# Use Puma as the app server
+gem "puma"
+# For better console experience
+gem "pry-rails"
+# Access an IRB console on exception pages or by using <%= console %> anywhere in the code.
+gem "web-console"
+gem "listen", ">= 3.0.5", "< 3.2"
+# Call "byebug" anywhere in the code to stop execution and get a debugger console
+gem "pry-byebug"
+
+gem "better_errors"
+gem "binding_of_caller"
+
+# To support ES6
+gem "sprockets", "~> 4.0.0.beta4"
+# Support ES6
+gem "babel-transpiler"
+# Use SCSS for stylesheets
+gem "sass-rails"
+# Use Uglifier as compressor for JavaScript assets
+gem "uglifier", ">= 1.3.0"
+
+gem "jquery-rails"
+gem "turbolinks"
+gem "selectize-rails"
+gem "bulma-rails"
+
+gem "rubocop"
+gem "rubocop-rails_config"
+
+gem "form_core"
+gem "duck_record"
+gem "closure_tree"
+gem "cocoon"
+gem "script_core", github: "rails-engine/script_core", submodules: true
+
+gem "graphviz"

Gemfile.lock

+GIT
+  remote: https://github.com/rails-engine/script_core.git
+  revision: f086b63c03061732c8a760b97d54a9d2e7cbec68
+  submodules: true
+  specs:
+    script_core (0.0.4)
+      msgpack (~> 1.0)
+      rake-compiler (~> 1.0)
+
+PATH
+  remote: .
+  specs:
+    workflow_core (0.0.1)
+      rails (~> 5.2)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    actioncable (5.2.1)
+      actionpack (= 5.2.1)
+      nio4r (~> 2.0)
+      websocket-driver (>= 0.6.1)
+    actionmailer (5.2.1)
+      actionpack (= 5.2.1)
+      actionview (= 5.2.1)
+      activejob (= 5.2.1)
+      mail (~> 2.5, >= 2.5.4)
+      rails-dom-testing (~> 2.0)
+    actionpack (5.2.1)
+      actionview (= 5.2.1)
+      activesupport (= 5.2.1)
+      rack (~> 2.0)
+      rack-test (>= 0.6.3)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.2)
+    actionview (5.2.1)
+      activesupport (= 5.2.1)
+      builder (~> 3.1)
+      erubi (~> 1.4)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.3)
+    activejob (5.2.1)
+      activesupport (= 5.2.1)
+      globalid (>= 0.3.6)
+    activemodel (5.2.1)
+      activesupport (= 5.2.1)
+    activerecord (5.2.1)
+      activemodel (= 5.2.1)
+      activesupport (= 5.2.1)
+      arel (>= 9.0)
+    activestorage (5.2.1)
+      actionpack (= 5.2.1)
+      activerecord (= 5.2.1)
+      marcel (~> 0.3.1)
+    activesupport (5.2.1)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
+      minitest (~> 5.1)
+      tzinfo (~> 1.1)
+    arel (9.0.0)
+    ast (2.4.0)
+    babel-source (5.8.35)
+    babel-transpiler (0.7.0)
+      babel-source (>= 4.0, < 6)
+      execjs (~> 2.0)
+    better_errors (2.5.0)
+      coderay (>= 1.0.0)
+      erubi (>= 1.0.0)
+      rack (>= 0.9.0)
+    bindex (0.5.0)
+    binding_of_caller (0.8.0)
+      debug_inspector (>= 0.0.1)
+    builder (3.2.3)
+    bulma-rails (0.7.1)
+      sass (~> 3.2)
+    byebug (10.0.2)
+    closure_tree (7.0.0)
+      activerecord (>= 4.2.10)
+      with_advisory_lock (>= 4.0.0)
+    cocoon (1.2.11)
+    coderay (1.1.2)
+    concurrent-ruby (1.0.5)
+    crass (1.0.4)
+    debug_inspector (0.0.3)
+    duck_record (0.0.26)
+      activemodel (~> 5.0)
+      activesupport (~> 5.0)
+    erubi (1.7.1)
+    execjs (2.7.0)
+    ffi (1.9.25)
+    form_core (0.0.14)
+      duck_record (~> 0)
+      rails (~> 5.0)
+    globalid (0.4.1)
+      activesupport (>= 4.2.0)
+    graphviz (1.1.0)
+      process-pipeline
+    i18n (1.1.0)
+      concurrent-ruby (~> 1.0)
+    jaro_winkler (1.5.1)
+    jquery-rails (4.3.3)
+      rails-dom-testing (>= 1, < 3)
+      railties (>= 4.2.0)
+      thor (>= 0.14, < 2.0)
+    listen (3.1.5)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+      ruby_dep (~> 1.2)
+    loofah (2.2.2)
+      crass (~> 1.0.2)
+      nokogiri (>= 1.5.9)
+    mail (2.7.0)
+      mini_mime (>= 0.1.1)
+    marcel (0.3.3)
+      mimemagic (~> 0.3.2)
+    method_source (0.9.0)
+    mimemagic (0.3.2)
+    mini_mime (1.0.1)
+    mini_portile2 (2.3.0)
+    minitest (5.11.3)
+    msgpack (1.2.4)
+    nio4r (2.3.1)
+    nokogiri (1.8.4)
+      mini_portile2 (~> 2.3.0)
+    parallel (1.12.1)
+    parser (2.5.1.2)
+      ast (~> 2.4.0)
+    powerpack (0.1.2)
+    process-group (1.1.0)
+    process-pipeline (1.0.1)
+      process-group
+    pry (0.11.3)
+      coderay (~> 1.1.0)
+      method_source (~> 0.9.0)
+    pry-byebug (3.6.0)
+      byebug (~> 10.0)
+      pry (~> 0.10)
+    pry-rails (0.3.6)
+      pry (>= 0.10.4)
+    puma (3.12.0)
+    rack (2.0.5)
+    rack-test (1.1.0)
+      rack (>= 1.0, < 3)
+    rails (5.2.1)
+      actioncable (= 5.2.1)
+      actionmailer (= 5.2.1)
+      actionpack (= 5.2.1)
+      actionview (= 5.2.1)
+      activejob (= 5.2.1)
+      activemodel (= 5.2.1)
+      activerecord (= 5.2.1)
+      activestorage (= 5.2.1)
+      activesupport (= 5.2.1)
+      bundler (>= 1.3.0)
+      railties (= 5.2.1)
+      sprockets-rails (>= 2.0.0)
+    rails-dom-testing (2.0.3)
+      activesupport (>= 4.2.0)
+      nokogiri (>= 1.6)
+    rails-html-sanitizer (1.0.4)
+      loofah (~> 2.2, >= 2.2.2)
+    railties (5.2.1)
+      actionpack (= 5.2.1)
+      activesupport (= 5.2.1)
+      method_source
+      rake (>= 0.8.7)
+      thor (>= 0.19.0, < 2.0)
+    rainbow (3.0.0)
+    rake (12.3.1)
+    rake-compiler (1.0.5)
+      rake
+    rb-fsevent (0.10.3)
+    rb-inotify (0.9.10)
+      ffi (>= 0.5.0, < 2)
+    rubocop (0.59.2)
+      jaro_winkler (~> 1.5.1)
+      parallel (~> 1.10)
+      parser (>= 2.5, != 2.5.1.1)
+      powerpack (~> 0.1)
+      rainbow (>= 2.2.2, < 4.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (~> 1.0, >= 1.0.1)
+    rubocop-rails_config (0.2.3)
+      railties (>= 3.0)
+      rubocop (~> 0.56)
+    ruby-progressbar (1.10.0)
+    ruby_dep (1.5.0)
+    sass (3.6.0)
+      sass-listen (~> 4.0.0)
+    sass-listen (4.0.0)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+    sass-rails (5.0.7)
+      railties (>= 4.0.0, < 6)
+      sass (~> 3.1)
+      sprockets (>= 2.8, < 4.0)
+      sprockets-rails (>= 2.0, < 4.0)
+      tilt (>= 1.1, < 3)
+    selectize-rails (0.12.5)
+    sprockets (4.0.0.beta8)
+      concurrent-ruby (~> 1.0)
+      rack (> 1, < 3)
+    sprockets-rails (3.2.1)
+      actionpack (>= 4.0)
+      activesupport (>= 4.0)
+      sprockets (>= 3.0.0)
+    sqlite3 (1.3.13)
+    thor (0.20.0)
+    thread_safe (0.3.6)
+    tilt (2.0.8)
+    turbolinks (5.2.0)
+      turbolinks-source (~> 5.2)
+    turbolinks-source (5.2.0)
+    tzinfo (1.2.5)
+      thread_safe (~> 0.1)
+    uglifier (4.1.19)
+      execjs (>= 0.3.0, < 3)
+    unicode-display_width (1.4.0)
+    web-console (3.7.0)
+      actionview (>= 5.0)
+      activemodel (>= 5.0)
+      bindex (>= 0.4.0)
+      railties (>= 5.0)
+    websocket-driver (0.7.0)
+      websocket-extensions (>= 0.1.0)
+    websocket-extensions (0.1.3)
+    with_advisory_lock (4.0.0)
+      activerecord (>= 4.2)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  babel-transpiler
+  better_errors
+  binding_of_caller
+  bulma-rails
+  closure_tree
+  cocoon
+  duck_record
+  form_core
+  graphviz
+  jquery-rails
+  listen (>= 3.0.5, < 3.2)
+  pry-byebug
+  pry-rails
+  puma
+  rubocop
+  rubocop-rails_config
+  sass-rails
+  script_core!
+  selectize-rails
+  sprockets (~> 4.0.0.beta4)
+  sqlite3
+  turbolinks
+  uglifier (>= 1.3.0)
+  web-console
+  workflow_core!
+
+BUNDLED WITH
+   1.16.4

MIT-LICENSE

+Copyright 2018 Jun Jiang
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

+Workflow Core
+====
+
+> WorkflowCore is under development, the codebase is unoptimized and has many bad practices, I may do breaking changes even force pushing to master branch.
+> 
+> In short, it's not ready yet, but I realize that a workflow engine is complicated to design and it needs a long term to done well, so I decide to open source at early stage.
+> 
+> Any way, feedbacks and suggestions are highly welcome!
+
+A Rails engine which providing essential infrastructure of workflow.
+
+It's based on [Workflow Net](http://mlwiki.org/index.php/Workflow_Nets) technique.
+
+The gem provides:
+
+- Models to describe workflow nets
+- Models to describe workflow instances
+- Interfaces to define transitions
+
+## Why “core”
+
+Because it's not aim to "out-of-box", some gem like Devise giving developer an out-of-box experience, that's awesome, but on the other hand, it also introducing a very complex abstraction that may hard to understanding how it works, especially when you attempting to customize it.
+
+I believe that the gem is tightly coupled with features that face to end users directly, so having a good customizability and easy to understanding are of the most concern, so I just wanna give you a domain framework that you can build your own that just fitting your need, and you shall have fully control and without any unnecessary abstraction.
+
+BTW, the dummy app is a full-featured app with production level codebase that you can freely to reference it.
+
+## Todo
+
+- Make sure transit must be an atomic operation, and help developers to avoiding Rails' nested transaction pitfalls.
+- Consider consequences of changing the Net, well handle Net changes. e.g: what about running instances?
+- Stabilizing interfaces.
+- Evaluate that can supporting async, scheduled and event-based transition properly.
+- Efficiency (especially database queries).
+- Easy to use.
+- Transforming to graph representation for visualization and other usages (e.g proving [Soundness](http://mlwiki.org/index.php/Workflow_Soundness)).
+- Polish codebase.
+- Continually improving dummy app.
+
+## Requirements
+
+- MRI 2.3+
+- Rails 5.0+
+
+## Usage
+
+See demo for now.
+
+## Installation
+
+Add this line to your Gemfile:
+
+```ruby
+gem 'workflow_core'
+```
+
+Or you may want to include the gem directly from GitHub:
+
+```ruby
+gem 'workflow_core', github: 'rails-engine/workflow_core'
+```
+
+And then execute:
+
+```sh
+$ bundle
+```
+
+Copy migrations
+
+```sh
+$ bin/rails workflow_core:install:migrations
+```
+
+Then do migrate
+
+```sh
+$ bin/rails db:migrate
+```
+
+## Demo
+
+**Demo is also under development.**
+
+The dummy app integrates with [Form Core](https://github.com/rails-engine/form_core) and [Script Core](https://github.com/rails-engine/script_core) shows an Approving Manage System.
+
+![](_assets/dummy_overview.png)
+
+### Features
+
+#### Importing workflow definitions from a BPMN2 xml,
+
+![](_assets/importing_bpmn.png)
+
+Because there isn't have a easy-to-use web-based flowchart designer, I implement a stupid BPMN2 importer, it have many restrictions:
+
+- Only supports `Sequence`, `Start event`, `End event`, `Parallel gateway` and `Exclusive gateway`
+- Using gateway to fork flows must have corresponding join (or merge) gateway
+- Only read `name` property, other such as `condition expression` must configure on the dummy app
+
+You can check `_samples` folder, I've already provided some samples, or you can try a BPMN2 designer (e.g [Camunda modeler](https://github.com/camunda/camunda-modeler)).
+
+#### Defining form
+
+![](_assets/defining_form.png)
+
+You can defining a dynamic form for a workflow.
+
+In transition's options, you can configure field's accessibility
+
+#### Exclusive choice configuration supports Ruby expression
+
+![](_assets/editing_transition.png)
+
+Exclusive choice is a special transition that needs to configure conditions that determine how to transit to a branch.
+
+The condition is a Ruby expression, and running in a mRuby sandbox (powered by ScriptCore but it's also undone yet), and you can access form data through `@input[:payload]`, for example, there is a field named `approved`, we can check the field checked by `@input[:payload]["approved"]`
+
+#### Run a workflow
+
+See `Instance` tab, that should make sense.
+
+### Usage
+
+**You need install Graphviz first**
+
+Clone the repository.
+
+```sh
+$ git clone https://github.com/rails-engine/workflow_core.git
+```
+
+Change directory
+
+```sh
+$ cd workflow_core
+```
+
+Run bundler
+
+```sh
+$ bundle install
+```
+
+Preparing database
+
+```sh
+$ bin/rails db:migrate
+```
+
+Start the Rails server
+
+```sh
+$ bin/rails s
+```
+
+Open your browser, and visit `http://localhost:3000`
+
+## Contributing
+
+Bug report or pull request are welcome.
+
+### Make a pull request
+
+1. Fork it
+2. Create your feature branch (`git checkout -b my-new-feature`)
+3. Commit your changes (`git commit -am 'Add some feature'`)
+4. Push to the branch (`git push origin my-new-feature`)
+5. Create new Pull Request
+
+Please write unit test with your code if necessary.
+
+## License
+
+The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).

Rakefile

+# frozen_string_literal: true
+
+begin
+  require "bundler/setup"
+rescue LoadError
+  puts "You must `gem install bundler` and `bundle install` to run rake tasks"
+end
+
+require "rdoc/task"
+
+RDoc::Task.new(:rdoc) do |rdoc|
+  rdoc.rdoc_dir = "rdoc"
+  rdoc.title    = "WorkflowCore"
+  rdoc.options << "--line-numbers"
+  rdoc.rdoc_files.include("README.md")
+  rdoc.rdoc_files.include("lib/**/*.rb")
+end
+
+APP_RAKEFILE = File.expand_path("test/dummy/Rakefile", __dir__)
+load "rails/tasks/engine.rake"
+
+load "rails/tasks/statistics.rake"
+
+require "bundler/gem_tasks"
+
+require "rake/testtask"
+
+Rake::TestTask.new(:test) do |t|
+  t.libs << "test"
+  t.pattern = "test/**/*_test.rb"
+  t.verbose = false
+end
+
+task default: :test

_samples/diagram_1.bpmn

+<?xml version="1.0" encoding="UTF-8"?>
+<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" id="Definitions_1ao30nf" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="2.0.1">
+  <bpmn:process id="Process_1" isExecutable="true">
+    <bpmn:startEvent id="StartEvent_1">
+      <bpmn:outgoing>SequenceFlow_0z87m50</bpmn:outgoing>
+    </bpmn:startEvent>
+    <bpmn:task id="Task_1jpb9fm" name="Step 1">
+      <bpmn:incoming>SequenceFlow_0z87m50</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_1ph0afh</bpmn:outgoing>
+    </bpmn:task>
+    <bpmn:sequenceFlow id="SequenceFlow_0z87m50" sourceRef="StartEvent_1" targetRef="Task_1jpb9fm" />
+    <bpmn:task id="Task_0rnfiox" name="Step 2">
+      <bpmn:incoming>SequenceFlow_1ph0afh</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_1h0vowt</bpmn:outgoing>
+    </bpmn:task>
+    <bpmn:sequenceFlow id="SequenceFlow_1ph0afh" sourceRef="Task_1jpb9fm" targetRef="Task_0rnfiox" />
+    <bpmn:endEvent id="EndEvent_0d80vbz">
+      <bpmn:incoming>SequenceFlow_1h0vowt</bpmn:incoming>
+    </bpmn:endEvent>
+    <bpmn:sequenceFlow id="SequenceFlow_1h0vowt" sourceRef="Task_0rnfiox" targetRef="EndEvent_0d80vbz" />
+  </bpmn:process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
+    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">
+      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="StartEvent_1">
+        <dc:Bounds x="173" y="102" width="36" height="36" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="Task_1jpb9fm_di" bpmnElement="Task_1jpb9fm">
+        <dc:Bounds x="259" y="80" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_0z87m50_di" bpmnElement="SequenceFlow_0z87m50">
+        <di:waypoint x="209" y="120" />
+        <di:waypoint x="259" y="120" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="Task_0rnfiox_di" bpmnElement="Task_0rnfiox">
+        <dc:Bounds x="409" y="80" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_1ph0afh_di" bpmnElement="SequenceFlow_1ph0afh">
+        <di:waypoint x="359" y="120" />
+        <di:waypoint x="409" y="120" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="EndEvent_0d80vbz_di" bpmnElement="EndEvent_0d80vbz">
+        <dc:Bounds x="559" y="102" width="36" height="36" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_1h0vowt_di" bpmnElement="SequenceFlow_1h0vowt">
+        <di:waypoint x="509" y="120" />
+        <di:waypoint x="559" y="120" />
+      </bpmndi:BPMNEdge>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</bpmn:definitions>

_samples/diagram_2.bpmn

+<?xml version="1.0" encoding="UTF-8"?>
+<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" id="Definitions_12bthnl" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="2.0.3">
+  <bpmn:process id="Process_1" isExecutable="true">
+    <bpmn:startEvent id="StartEvent_1">
+      <bpmn:outgoing>SequenceFlow_0ihulyl</bpmn:outgoing>
+    </bpmn:startEvent>
+    <bpmn:task id="Task_0f5ie7w" name="Step 1">
+      <bpmn:incoming>SequenceFlow_0ihulyl</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_1wljg2h</bpmn:outgoing>
+    </bpmn:task>
+    <bpmn:sequenceFlow id="SequenceFlow_0ihulyl" sourceRef="StartEvent_1" targetRef="Task_0f5ie7w" />
+    <bpmn:sequenceFlow id="SequenceFlow_1wljg2h" sourceRef="Task_0f5ie7w" targetRef="ExclusiveGateway_01sqwfm" />
+    <bpmn:parallelGateway id="ExclusiveGateway_01sqwfm" name="Parallel Split">
+      <bpmn:incoming>SequenceFlow_1wljg2h</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_190bkby</bpmn:outgoing>
+      <bpmn:outgoing>SequenceFlow_03lhyba</bpmn:outgoing>
+    </bpmn:parallelGateway>
+    <bpmn:task id="Task_0ac7qx7" name="Step 2a">
+      <bpmn:incoming>SequenceFlow_190bkby</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_047f1j5</bpmn:outgoing>
+    </bpmn:task>
+    <bpmn:sequenceFlow id="SequenceFlow_190bkby" sourceRef="ExclusiveGateway_01sqwfm" targetRef="Task_0ac7qx7" />
+    <bpmn:task id="Task_0ym8z2m" name="Step 2b">
+      <bpmn:incoming>SequenceFlow_03lhyba</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_0rl07dr</bpmn:outgoing>
+    </bpmn:task>
+    <bpmn:sequenceFlow id="SequenceFlow_03lhyba" sourceRef="ExclusiveGateway_01sqwfm" targetRef="Task_0ym8z2m" />
+    <bpmn:sequenceFlow id="SequenceFlow_047f1j5" sourceRef="Task_0ac7qx7" targetRef="ExclusiveGateway_1ni4fs4" />
+    <bpmn:parallelGateway id="ExclusiveGateway_1ni4fs4" name="Synchronization">
+      <bpmn:incoming>SequenceFlow_047f1j5</bpmn:incoming>
+      <bpmn:incoming>SequenceFlow_0rl07dr</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_1a0tblh</bpmn:outgoing>
+    </bpmn:parallelGateway>
+    <bpmn:sequenceFlow id="SequenceFlow_0rl07dr" sourceRef="Task_0ym8z2m" targetRef="ExclusiveGateway_1ni4fs4" />
+    <bpmn:task id="Task_0h6xqca" name="Step 3">
+      <bpmn:incoming>SequenceFlow_1a0tblh</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_18vdzfl</bpmn:outgoing>
+    </bpmn:task>
+    <bpmn:sequenceFlow id="SequenceFlow_1a0tblh" sourceRef="ExclusiveGateway_1ni4fs4" targetRef="Task_0h6xqca" />
+    <bpmn:endEvent id="EndEvent_0lta3qi">
+      <bpmn:incoming>SequenceFlow_18vdzfl</bpmn:incoming>
+    </bpmn:endEvent>
+    <bpmn:sequenceFlow id="SequenceFlow_18vdzfl" sourceRef="Task_0h6xqca" targetRef="EndEvent_0lta3qi" />
+  </bpmn:process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
+    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">
+      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="StartEvent_1">
+        <dc:Bounds x="173" y="102" width="36" height="36" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="Task_0f5ie7w_di" bpmnElement="Task_0f5ie7w">
+        <dc:Bounds x="259" y="80" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_0ihulyl_di" bpmnElement="SequenceFlow_0ihulyl">
+        <di:waypoint x="209" y="120" />
+        <di:waypoint x="259" y="120" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNEdge id="SequenceFlow_1wljg2h_di" bpmnElement="SequenceFlow_1wljg2h">
+        <di:waypoint x="359" y="120" />
+        <di:waypoint x="409" y="120" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="ParallelGateway_0ukzmc6_di" bpmnElement="ExclusiveGateway_01sqwfm">
+        <dc:Bounds x="409" y="95" width="50" height="50" />
+        <bpmndi:BPMNLabel>
+          <dc:Bounds x="484" y="110" width="62" height="14" />
+        </bpmndi:BPMNLabel>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="Task_0ac7qx7_di" bpmnElement="Task_0ac7qx7">
+        <dc:Bounds x="509" y="-19" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_190bkby_di" bpmnElement="SequenceFlow_190bkby">
+        <di:waypoint x="434" y="95" />
+        <di:waypoint x="434" y="21" />
+        <di:waypoint x="509" y="21" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="Task_0ym8z2m_di" bpmnElement="Task_0ym8z2m">
+        <dc:Bounds x="509" y="190" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_03lhyba_di" bpmnElement="SequenceFlow_03lhyba">
+        <di:waypoint x="434" y="145" />
+        <di:waypoint x="434" y="230" />
+        <di:waypoint x="509" y="230" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNEdge id="SequenceFlow_047f1j5_di" bpmnElement="SequenceFlow_047f1j5">
+        <di:waypoint x="609" y="21" />
+        <di:waypoint x="685" y="21" />
+        <di:waypoint x="685" y="95" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="ParallelGateway_14q60vy_di" bpmnElement="ExclusiveGateway_1ni4fs4">
+        <dc:Bounds x="660" y="95" width="50" height="50" />
+        <bpmndi:BPMNLabel>
+          <dc:Bounds x="566" y="110" width="79" height="14" />
+        </bpmndi:BPMNLabel>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_0rl07dr_di" bpmnElement="SequenceFlow_0rl07dr">
+        <di:waypoint x="609" y="230" />
+        <di:waypoint x="685" y="230" />
+        <di:waypoint x="685" y="145" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="Task_0h6xqca_di" bpmnElement="Task_0h6xqca">
+        <dc:Bounds x="761" y="80" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_1a0tblh_di" bpmnElement="SequenceFlow_1a0tblh">
+        <di:waypoint x="710" y="120" />
+        <di:waypoint x="761" y="120" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="EndEvent_0lta3qi_di" bpmnElement="EndEvent_0lta3qi">
+        <dc:Bounds x="912" y="102" width="36" height="36" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_18vdzfl_di" bpmnElement="SequenceFlow_18vdzfl">
+        <di:waypoint x="861" y="120" />
+        <di:waypoint x="912" y="120" />
+      </bpmndi:BPMNEdge>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</bpmn:definitions>

_samples/diagram_3.bpmn

+<?xml version="1.0" encoding="UTF-8"?>
+<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" id="Definitions_0w9rj1f" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="2.0.3">
+  <bpmn:process id="Process_1" isExecutable="true">
+    <bpmn:startEvent id="StartEvent_1">
+      <bpmn:outgoing>SequenceFlow_0qzo3lb</bpmn:outgoing>
+    </bpmn:startEvent>
+    <bpmn:task id="Task_07nyace" name="Step 1">
+      <bpmn:incoming>SequenceFlow_0qzo3lb</bpmn:incoming>
+      <bpmn:incoming>SequenceFlow_1fr8c9x</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_0v54qlb</bpmn:outgoing>
+    </bpmn:task>
+    <bpmn:sequenceFlow id="SequenceFlow_0qzo3lb" sourceRef="StartEvent_1" targetRef="Task_07nyace" />
+    <bpmn:exclusiveGateway id="ExclusiveGateway_1jpd3ln">
+      <bpmn:incoming>SequenceFlow_0v54qlb</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_1s8t845</bpmn:outgoing>
+      <bpmn:outgoing>SequenceFlow_1fr8c9x</bpmn:outgoing>
+    </bpmn:exclusiveGateway>
+    <bpmn:sequenceFlow id="SequenceFlow_0v54qlb" sourceRef="Task_07nyace" targetRef="ExclusiveGateway_1jpd3ln" />
+    <bpmn:task id="Task_0ym21fx" name="Step 2">
+      <bpmn:incoming>SequenceFlow_1s8t845</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_0nzmb8s</bpmn:outgoing>
+    </bpmn:task>
+    <bpmn:sequenceFlow id="SequenceFlow_1s8t845" sourceRef="ExclusiveGateway_1jpd3ln" targetRef="Task_0ym21fx" />
+    <bpmn:endEvent id="EndEvent_1jlbp8k">
+      <bpmn:incoming>SequenceFlow_0nzmb8s</bpmn:incoming>
+    </bpmn:endEvent>
+    <bpmn:sequenceFlow id="SequenceFlow_0nzmb8s" sourceRef="Task_0ym21fx" targetRef="EndEvent_1jlbp8k" />
+    <bpmn:sequenceFlow id="SequenceFlow_1fr8c9x" sourceRef="ExclusiveGateway_1jpd3ln" targetRef="Task_07nyace" />
+  </bpmn:process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
+    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">
+      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="StartEvent_1">
+        <dc:Bounds x="173" y="102" width="36" height="36" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="Task_07nyace_di" bpmnElement="Task_07nyace">
+        <dc:Bounds x="259" y="80" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_0qzo3lb_di" bpmnElement="SequenceFlow_0qzo3lb">
+        <di:waypoint x="209" y="120" />
+        <di:waypoint x="259" y="120" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="ExclusiveGateway_1jpd3ln_di" bpmnElement="ExclusiveGateway_1jpd3ln" isMarkerVisible="true">
+        <dc:Bounds x="409" y="95" width="50" height="50" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_0v54qlb_di" bpmnElement="SequenceFlow_0v54qlb">
+        <di:waypoint x="359" y="120" />
+        <di:waypoint x="409" y="120" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="Task_0ym21fx_di" bpmnElement="Task_0ym21fx">
+        <dc:Bounds x="509" y="80" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_1s8t845_di" bpmnElement="SequenceFlow_1s8t845">
+        <di:waypoint x="459" y="120" />
+        <di:waypoint x="509" y="120" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="EndEvent_1jlbp8k_di" bpmnElement="EndEvent_1jlbp8k">
+        <dc:Bounds x="659" y="102" width="36" height="36" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_0nzmb8s_di" bpmnElement="SequenceFlow_0nzmb8s">
+        <di:waypoint x="609" y="120" />
+        <di:waypoint x="659" y="120" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNEdge id="SequenceFlow_1fr8c9x_di" bpmnElement="SequenceFlow_1fr8c9x">
+        <di:waypoint x="434" y="120" />
+        <di:waypoint x="434" y="30" />
+        <di:waypoint x="309" y="30" />
+        <di:waypoint x="309" y="80" />
+      </bpmndi:BPMNEdge>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</bpmn:definitions>

app/jobs/workflow_core/application_job.rb

+# frozen_string_literal: true
+
+module WorkflowCore
+  class ApplicationJob < ActiveJob::Base
+  end
+end

app/models/workflow_core/application_record.rb

+# frozen_string_literal: true
+
+module WorkflowCore
+  class ApplicationRecord < ActiveRecord::Base
+    self.abstract_class = true
+  end
+end

app/models/workflow_core/place.rb

+# frozen_string_literal: true
+
+module WorkflowCore
+  class Place < ApplicationRecord
+    self.table_name = "workflow_places"
+
+    belongs_to :workflow
+
+    belongs_to :input_transition, optional: true, foreign_key: "input_transition_id",
+               class_name: "WorkflowCore::Transition"
+    belongs_to :output_transition, optional: true, foreign_key: "output_transition_id",
+               class_name: "WorkflowCore::Transition"
+
+    has_many :tokens
+  end
+end

app/models/workflow_core/token.rb

+# frozen_string_literal: true
+
+module WorkflowCore
+  class Token < ApplicationRecord
+    self.table_name = "workflow_tokens"
+
+    belongs_to :instance,
+               class_name: "WorkflowCore::WorkflowInstance"
+    belongs_to :workflow
+
+    belongs_to :place
+    belongs_to :previous, optional: true,
+               class_name: "WorkflowCore::Token"
+
+    enum status: {
+      processing: 0,
+      completed: 1,
+      failed: 2,
+      unexpected: 3,
+      terminated: 4
+    }
+  end
+end

app/models/workflow_core/transition.rb

+# frozen_string_literal: true
+
+module WorkflowCore
+  class Transition < ApplicationRecord
+    self.table_name = "workflow_transitions"
+
+    belongs_to :workflow
+
+    has_many :input_places, dependent: :nullify,
+             foreign_key: "output_transition_id", class_name: "WorkflowCore::Place"
+    has_many :output_places, dependent: :destroy,
+             foreign_key: "input_transition_id", class_name: "WorkflowCore::Place"
+
+    def fire(_token)
+      raise NotImplementedError
+    end
+  end
+end

app/models/workflow_core/workflow.rb

+# frozen_string_literal: true
+
+module WorkflowCore
+  class Workflow < ApplicationRecord
+    self.table_name = "workflows"
+
+    has_one :start_place, class_name: "WorkflowCore::Place", dependent: :destroy
+
+    has_many :transitions, class_name: "WorkflowCore::Transition", dependent: :destroy
+    has_many :places, class_name: "WorkflowCore::Place", dependent: :destroy
+
+    has_many :instances, class_name: "WorkflowCore::WorkflowInstance", dependent: :destroy
+    has_many :tokens, class_name: "WorkflowCore::Token", dependent: :destroy
+  end
+end

app/models/workflow_core/workflow_instance.rb

+# frozen_string_literal: true
+
+module WorkflowCore
+  class WorkflowInstance < ApplicationRecord
+    self.table_name = "workflow_instances"
+
+    belongs_to :workflow
+    has_many :tokens, foreign_key: "instance_id", dependent: :destroy
+
+    enum status: {
+      processing: 0,
+      completed: 1,
+      failed: 2,
+      unexpected: 3,
+      terminated: 4
+    }
+
+    serialize :payload
+  end
+end

bin/rails

+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# This command will automatically be run when you run "rails" with Rails gems
+# installed from the root of your application.
+
+ENGINE_ROOT = File.expand_path("..", __dir__)
+ENGINE_PATH = File.expand_path("../lib/workflow_core/engine", __dir__)
+APP_PATH = File.expand_path("../test/dummy/config/application", __dir__)
+
+# Set up gems listed in the Gemfile.
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../Gemfile", __dir__)
+require "bundler/setup" if File.exist?(ENV["BUNDLE_GEMFILE"])
+
+require "rails/all"
+require "rails/engine/commands"

db/migrate/20180910195950_create_workflows.rb

+# frozen_string_literal: true
+
+class CreateWorkflows < ActiveRecord::Migration[5.2]
+  def change
+    create_table :workflows do |t|
+      t.string :type, null: false
+      t.timestamps
+    end
+  end
+end

db/migrate/20180910200203_create_workflow_places.rb

+# frozen_string_literal: true
+
+class CreateWorkflowPlaces < ActiveRecord::Migration[5.2]
+  def change
+    create_table :workflow_places do |t|
+      t.references :input_transition, foreign_key: {to_table: "workflow_transitions"}
+      t.references :output_transition, foreign_key: {to_table: "workflow_transitions"}
+
+      t.string :type, null: false
+      t.references :workflow, foreign_key: true
+      t.timestamps
+    end
+  end
+end

db/migrate/20180910200454_create_workflow_transitions.rb

+# frozen_string_literal: true
+
+class CreateWorkflowTransitions < ActiveRecord::Migration[5.2]
+  def change
+    create_table :workflow_transitions do |t|
+      t.string :type, null: false
+      t.references :workflow, foreign_key: true
+      t.timestamps
+    end
+  end
+end

db/migrate/20180912223642_create_workflow_instances.rb

+# frozen_string_literal: true
+
+class CreateWorkflowInstances < ActiveRecord::Migration[5.2]
+  def change
+    create_table :workflow_instances do |t|
+      t.text :payload
+      t.integer :status, null: false, default: 0
+
+      t.references :workflow, foreign_key: true
+      t.timestamps
+    end
+  end
+end

db/migrate/20180912223722_create_workflow_tokens.rb

+# frozen_string_literal: true
+
+class CreateWorkflowTokens < ActiveRecord::Migration[5.2]
+  def change
+    create_table :workflow_tokens do |t|
+      t.integer :status, null: false, default: 0
+
+      t.references :place, foreign_key: {to_table: "workflow_places"}
+      t.references :previous, foreign_key: {to_table: "workflow_tokens"}
+
+      t.references :instance, foreign_key: {to_table: "workflow_instances"}
+      t.references :workflow, foreign_key: true
+      t.timestamps
+    end
+  end
+end

lib/tasks/workflow_core_tasks.rake

+# frozen_string_literal: true
+
+# desc "Explaining what the task does"
+# task :workflow_core do
+#   # Task goes here
+# end

lib/workflow_core.rb

+# frozen_string_literal: true
+
+require "workflow_core/engine"
+
+module WorkflowCore
+  # Your code goes here...
+end

lib/workflow_core/engine.rb

+# frozen_string_literal: true
+
+module WorkflowCore
+  class Engine < ::Rails::Engine
+    isolate_namespace WorkflowCore
+  end
+end

lib/workflow_core/version.rb

+# frozen_string_literal: true
+
+module WorkflowCore
+  VERSION = "0.0.1"
+end

test/dummy/.ruby-version

+ruby-2.5.1
\ No newline at end of file

test/dummy/Rakefile

+# frozen_string_literal: true
+
+# Add your own tasks in files placed in lib/tasks ending in .rake,
+# for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.
+
+require_relative "config/application"
+
+Rails.application.load_tasks

test/dummy/app/assets/config/manifest.js

+//= link_tree ../images
+//= link_directory ../javascripts .js
+//= link_directory ../stylesheets .css

test/dummy/app/assets/javascripts/application.es6

+//= require rails-ujs
+//= require turbolinks
+//= require jquery3
+
+//= require selectize
+//= require cocoon
+
+// Cheat form https://github.com/jgthms/bulma/blob/master/docs/_javascript/main.js
+document.addEventListener('DOMContentLoaded', () => {
+
+  // Dropdowns
+
+  const $dropdowns = getAll('.dropdown:not(.is-hoverable)');
+
+  if ($dropdowns.length > 0) {
+    $dropdowns.forEach($el => {
+      $el.addEventListener('click', event => {
+        event.stopPropagation();
+        $el.classList.toggle('is-active');
+      });
+    });
+
+    document.addEventListener('click', event => {
+      closeDropdowns();
+    });
+  }
+
+  function closeDropdowns() {
+    $dropdowns.forEach($el => {
+      $el.classList.remove('is-active');
+    });
+  }
+
+  // Functions
+
+  function getAll(selector) {
+    return Array.prototype.slice.call(document.querySelectorAll(selector), 0);
+  }
+
+  // Utils
+
+  function removeFromArray(array, value) {
+    if (array.includes(value)) {
+      const value_index = array.indexOf(value);
+      array.splice(value_index, 1);
+    }
+
+    return array;
+  }
+
+  Array.prototype.diff = function (a) {
+    return this.filter(function (i) {
+      return a.indexOf(i) < 0;
+    });
+  };
+});

test/dummy/app/assets/stylesheets/application.scss

+@import "selectize";
+@import "bulma";
+
+body {
+  display: flex;
+  min-height: 100vh;
+  flex-direction: column;
+
+  & nav.nav {
+    a.brand {
+      padding: 0.5rem 0.75em 0.5em 0;
+    }
+  }
+
+  & .main {
+    flex: 1;
+  }
+
+  & footer.footer {
+    padding: 3rem 1.5rem 3rem;
+  }
+}
+
+.flash {
+  overflow: hidden;
+  top: 0;
+  left: 0;
+  right: 0;
+  line-height: 2.5;
+  background: $info;
+  color: $text-invert;
+  text-align: center;
+}
+
+#alert {
+  background: $danger;
+}
+
+.nested_form_field {
+  .collection {
+    .nested_form {
+      border: 1px solid $green;
+      padding: 0.5em;
+      margin-left: 0.75em;
+      margin-bottom: 0.75rem;
+    }
+  }
+}
+
+.content {
+  .nested-content {
+    margin-left: 0.75em;
+    margin-bottom: 1em;
+  }
+}
+
+.message-body.content {
+  > :first-child {
+    margin-top: 0;
+  }
+}
+
+.field {
+  flex: 1;
+}

test/dummy/app/controllers/application_controller.rb

+# frozen_string_literal: true
+
+class ApplicationController < ActionController::Base
+  helper_method :current_user
+
+  private
+
+  def current_user
+    @_current_user ||=
+      if session[:current_user_id].present?
+        User.where(id: session[:current_user_id]).first
+      else
+        nil
+      end
+  end
+
+  def require_signed_in
+    unless current_user
+      redirect_to users_url
+    end
+  end
+end

test/dummy/app/controllers/groups_controller.rb

+# frozen_string_literal: true
+
+class GroupsController < ApplicationController
+  before_action :set_group, only: [:show, :edit, :update, :destroy]
+
+  # GET /groups
+  def index
+    # https://ruby-china.org/topics/32802
+    @groups = Group.includes(:parent)
+  end
+
+  # GET /groups/new
+  def new
+    @group = Group.new
+  end
+
+  # GET /groups/1/edit
+  def edit
+  end
+
+  # POST /groups
+  def create
+    @group = Group.new(group_params)
+
+    if @group.save
+      redirect_to groups_url, notice: "Group was successfully created."
+    else
+      render :new
+    end
+  end
+
+  # PATCH/PUT /groups/1
+  def update
+    if @group.update(group_params)
+      redirect_to groups_url, notice: "Group was successfully updated."
+    else
+      render :edit
+    end
+  end
+
+  # DELETE /groups/1
+  def destroy
+    @group.destroy
+    redirect_to groups_url, notice: "Group was successfully destroyed."
+  end
+
+  private
+  # Use callbacks to share common setup or constraints between actions.
+  def set_group
+    @group = Group.find(params[:id])
+  end
+
+  # Only allow a trusted parameter "white list" through.
+  def group_params
+    params.require(:group).permit(:name, :parent_id)
+  end
+end

test/dummy/app/controllers/sessions_controller.rb

+# frozen_string_literal: true
+
+class SessionsController < ApplicationController
+  def create
+    session[:current_user_id] = params[:user_id]
+    redirect_back fallback_location: root_url
+  end
+
+  def destroy
+    session[:current_user_id] = nil
+    redirect_to root_url
+  end
+end

test/dummy/app/controllers/users_controller.rb

+# frozen_string_literal: true
+
+class UsersController < ApplicationController
+  before_action :set_user, only: [:show, :edit, :update, :destroy]
+
+  # GET /users
+  def index
+    @users = User.all.includes(:group)
+  end
+
+  # GET /users/new
+  def new
+    @user = User.new
+  end
+
+  # GET /users/1/edit
+  def edit
+  end
+
+  # POST /users
+  def create
+    @user = User.new(user_params)
+
+    if @user.save
+      redirect_to users_url, notice: "User was successfully created."
+    else
+      render :new
+    end
+  end
+
+  # PATCH/PUT /users/1
+  def update
+    if @user.update(user_params)
+      redirect_to users_url, notice: "User was successfully updated."
+    else
+      render :edit
+    end
+  end
+
+  # DELETE /users/1
+  def destroy
+    @user.destroy
+    redirect_to users_url, notice: "User was successfully destroyed."
+  end
+
+  private
+  # Use callbacks to share common setup or constraints between actions.
+  def set_user
+    @user = User.find(params[:id])
+  end
+
+  # Only allow a trusted parameter "white list" through.
+  def user_params
+    params.require(:user).permit(:name, :group_id)
+  end
+end

test/dummy/app/controllers/workflows/application_controller.rb

+# frozen_string_literal: true
+
+class Workflows::ApplicationController < ApplicationController
+  layout "workflows"
+
+  before_action :set_workflow
+
+  protected
+
+  # Use callbacks to share common setup or constraints between actions.
+  def set_workflow
+    @workflow = Workflow.find(params[:workflow_id])
+  end
+end

test/dummy/app/controllers/workflows/fields/application_controller.rb

+# frozen_string_literal: true
+
+module Workflows
+  class Fields::ApplicationController < ApplicationController
+    before_action :set_form
+    before_action :set_field
+
+    protected
+
+    # Use callbacks to share common setup or constraints between actions.
+    def set_form
+      @form = @workflow.form
+    end
+
+    def set_field
+      @field = @form.fields.find(params[:field_id])
+    end
+  end
+end

test/dummy/app/controllers/workflows/fields/options_controller.rb

+# frozen_string_literal: true
+
+module Workflows
+  class Fields::OptionsController < Fields::ApplicationController
+    before_action :set_options
+
+    def edit
+    end
+
+    def update
+      @options.assign_attributes(options_params)
+      if @options.valid? && @field.save(validate: false)
+        redirect_to workflow_fields_url(@workflow), notice: "Field was successfully updated."
+      else
+        render :edit
+      end
+    end
+
+    private
+
+    def set_options
+      @options = @field.options
+    end
+
+    def options_params
+      params.fetch(:options, {}).permit!
+    end
+  end
+end

test/dummy/app/controllers/workflows/fields/validations_controller.rb

+# frozen_string_literal: true
+
+module Workflows
+  class Fields::ValidationsController < Fields::ApplicationController
+    before_action :set_validations
+
+    def edit
+    end
+
+    def update
+      @validations.assign_attributes(validations_params)
+      if @validations.valid? && @field.save(validate: false)
+        redirect_to workflow_fields_url(@workflow), notice: "Field was successfully updated."
+      else
+        render :edit
+      end
+    end
+
+    private
+
+    def set_validations
+      @validations = @field.validations
+    end
+
+    def validations_params
+      params.fetch(:validations, {}).permit!
+    end
+  end
+end

test/dummy/app/controllers/workflows/fields_controller.rb

+# frozen_string_literal: true
+
+class Workflows::FieldsController < Workflows::ApplicationController
+  before_action :set_form
+  before_action :set_field, only: %i[show edit update destroy]
+
+  # GET /workflows/1/fields
+  def index
+    @fields = @form.fields.all
+  end
+
+  # GET /workflows/fields/new
+  def new
+    @field = @form.fields.build
+  end
+
+  # GET /workflows/1/fields/1/edit
+  def edit
+  end
+
+  # POST /workflows/1/fields
+  def create
+    @field = @form.fields.build(field_params)
+
+    if @field.save
+      redirect_to workflow_fields_url(@workflow), notice: "Field was successfully created."
+    else
+      render :new
+    end
+  end
+
+  # PATCH/PUT /workflows/1/fields/1
+  def update
+    if @field.update(field_params)
+      redirect_to workflow_fields_url(@workflow), notice: "Field was successfully updated."
+    else
+      render :edit
+    end
+  end
+
+  # DELETE /workflows/1/fields/1
+  def destroy
+    @field.destroy
+    redirect_to workflow_fields_url(@workflow), notice: "Field was successfully destroyed."
+  end
+
+  private
+
+  # Use callbacks to share common setup or constraints between actions.
+  def set_form
+    @form = @workflow.form
+  end
+
+  def set_field
+    @field = @form.fields.find(params[:id])
+  end
+
+  # Only allow a trusted parameter "white list" through.
+  def field_params
+    params.fetch(:field, {}).permit(:name, :label, :hint, :type)
+  end
+end

test/dummy/app/controllers/workflows/instances/application_controller.rb

+# frozen_string_literal: true
+
+module Workflows
+  class Instances::ApplicationController < ApplicationController
+    layout "workflow_instances"
+
+    before_action :set_instance
+
+    protected
+
+    # Use callbacks to share common setup or constraints between actions.
+    def set_instance
+      @instance = @workflow.instances.find(params[:instance_id])
+    end
+  end
+end

test/dummy/app/controllers/workflows/instances/tokens_controller.rb

+# frozen_string_literal: true
+
+module Workflows
+  class Instances::TokensController < Instances::ApplicationController
+    before_action :set_token, only: %i[show fire]
+    before_action :set_form_model, only: %i[show fire]
+
+    # GET /workflows/1/tokens
+    def index
+      @tokens = @instance.tokens.includes(place: :output_transition)
+    end
+
+    # POST /workflows/1/tokens/1/fire
+    def show
+      @form_record = @virtual_model.load(@instance.payload)
+    end
+
+    # POST /workflows/1/tokens/1/fire
+    def fire
+      @form_record = @virtual_model.load(@instance.payload)
+      @form_record.assign_attributes(form_record_params)
+
+      if @form_record.valid?
+        @instance.update! payload: (@instance.payload || {}).merge(@form_record.serializable_hash)
+        @token.place.output_transition.fire(@token)
+
+        redirect_to workflow_instance_tokens_url(@workflow, @instance), notice: "Token was successfully fired."
+      else
+        render :show
+      end
+    end
+
+    private
+
+    # Use callbacks to share common setup or constraints between actions.
+    def set_token
+      @token = @instance.tokens.find(params[:id] || params[:token_id])
+    end
+
+    def set_form_model
+      @form = @workflow.form
+      overrides = @token.place.output_transition.options.field_overrides.map { |o| {o.name => {accessibility: o.accessibility}} }.reduce(&:merge)
+      @virtual_model = @form.to_virtual_model overrides: overrides
+    end
+
+    def form_record_params
+      params.fetch(:form_record, {}).permit!
+    end
+  end
+end

test/dummy/app/controllers/workflows/instances_controller.rb

+# frozen_string_literal: true
+
+class Workflows::InstancesController < Workflows::ApplicationController
+  before_action :set_instance, only: %i[show]
+
+  # GET /workflows/1/instances
+  def index
+    @instances = @workflow.instances.all
+  end
+
+  # GET /workflows/1/instances
+  def show
+    @form = @workflow.form
+    @virtual_model = @form.to_virtual_model
+    @form_record = @virtual_model.load(@instance.payload)
+
+    render layout: "workflow_instances"
+  end
+
+  # POST /workflows/1/instances
+  def create
+    @workflow.instances.create! type: "WorkflowInstance"
+
+    redirect_to workflow_instances_url(@workflow), notice: "instance was successfully created."
+  end
+
+  private
+
+  # Use callbacks to share common setup or constraints between actions.
+  def set_instance
+    @instance = @workflow.instances.find(params[:id])
+  end
+end

test/dummy/app/controllers/workflows/loads_controller.rb

+# frozen_string_literal: true
+
+class Workflows::LoadsController < Workflows::ApplicationController
+  # GET /workflows/1/load
+  def show
+  end
+
+  # PATCH/PUT /workflows/1/load
+  def update
+    bpmn_xml = permitted_params[:bpmn_xml].present? ? permitted_params[:bpmn_xml] : permitted_params[:bpmn_file]&.read
+    @workflow.load_from_bpmn!(bpmn_xml)
+
+    redirect_to workflow_url(@workflow), notice: "Workflow definition was successfully imported."
+  end
+
+  private
+  # Only allow a trusted parameter "white list" through.
+  def permitted_params
+    params.permit(:bpmn_xml, :bpmn_file)
+  end
+end

test/dummy/app/controllers/workflows/transitions/application_controller.rb

+# frozen_string_literal: true
+
+module Workflows
+  class Transitions::ApplicationController < ApplicationController
+    before_action :set_transition
+
+    protected
+
+    # Use callbacks to share common setup or constraints between actions.
+    def set_transition
+      @transition = @workflow.transitions.find(params[:transition_id])
+    end
+  end
+end

test/dummy/app/controllers/workflows/transitions/options_controller.rb

+# frozen_string_literal: true
+
+module Workflows
+  class Transitions::OptionsController < Transitions::ApplicationController
+    before_action :set_options
+
+    def edit
+    end
+
+    def update
+      @options.assign_attributes(options_params)
+      if @options.valid? && @transition.save(validate: false)
+        redirect_to workflow_transitions_url(@workflow), notice: "Transition was successfully updated."
+      else
+        render :edit
+      end
+    end
+
+    private
+
+    def set_options
+      @options = @transition.options
+    end
+
+    def options_params
+      params.fetch(:options, {}).permit!
+    end
+  end
+end

test/dummy/app/controllers/workflows/transitions_controller.rb

+# frozen_string_literal: true
+
+class Workflows::TransitionsController < Workflows::ApplicationController
+  before_action :set_transition, only: %i[edit update destroy]
+
+  # GET /workflows/1/transitions
+  def index
+    @transitions = @workflow.transitions.all
+  end
+
+  # GET /workflows/transitions/new
+  def new
+    @transition = @workflow.transitions.build
+  end
+
+  # GET /workflows/1/transitions/1/edit
+  def edit
+  end
+
+  # POST /workflows/1/transitions
+  def create
+    @transition = @workflow.transitions.build(transition_params)
+
+    if @transition.save
+      redirect_to workflow_transitions_url(@workflow), notice: "transition was successfully created."
+    else
+      render :new
+    end
+  end
+
+  # PATCH/PUT /workflows/1/transitions/1
+  def update
+    if @transition.update(transition_params)
+      redirect_to workflow_transitions_url(@workflow), notice: "transition was successfully updated."
+    else
+      render :edit
+    end
+  end
+
+  # DELETE /workflows/1/transitions/1
+  def destroy
+    @transition.destroy
+    redirect_to workflow_transitions_url(@workflow), notice: "transition was successfully destroyed."
+  end
+
+  private
+
+  # Use callbacks to share common setup or constraints between actions.
+  def set_transition
+    @transition = @workflow.transitions.find(params[:id])
+  end
+
+  # Only allow a trusted parameter "white list" through.
+  def transition_params
+    params.fetch(:transition, {}).permit(:name, :type)
+  end
+end

test/dummy/app/controllers/workflows_controller.rb

+# frozen_string_literal: true
+
+class WorkflowsController < ApplicationController
+  layout "application"
+
+  before_action :set_workflow, only: %i[show edit update destroy]
+
+  # GET /workflows
+  def index
+    @workflows = Workflow.all
+  end
+
+  # GET /workflows/new
+  def new
+    @workflow = Workflow.new
+  end
+
+  # GET /workflows/1
+  def show
+    render layout: "workflows"
+  end
+
+  # GET /workflows/1/edit
+  def edit
+  end
+
+  # POST /workflows
+  def create
+    @workflow = Workflow.new(workflow_params)
+
+    if @workflow.save
+      redirect_to workflow_url(@workflow), notice: "workflow was successfully created."
+    else
+      render :new
+    end
+  end
+
+  # PATCH/PUT /workflows/1
+  def update
+    if @workflow.update(workflow_params)
+      redirect_to workflow_url(@workflow), notice: "workflow was successfully updated."
+    else
+      render :edit
+    end
+  end
+
+  # DELETE /workflows/1
+  def destroy
+    @workflow.destroy
+    redirect_to workflows_url, notice: "workflow was successfully destroyed."
+  end
+
+  private
+
+  # Use callbacks to share common setup or constraints between actions.
+  def set_workflow
+    @workflow = Workflow.find(params[:id])
+  end
+
+  # Only allow a trusted parameter "white list" through.
+  def workflow_params
+    params.fetch(:workflow, {}).permit(:name, :description)
+  end
+end

test/dummy/app/helpers/application_helper.rb

+# frozen_string_literal: true
+
+module ApplicationHelper
+  def options_for_enum_select(klass, attribute, selected = nil)
+    container = klass.public_send(attribute.to_s.pluralize).map do |k, v|
+      v ||= k
+      [klass.human_enum_value(attribute, k), v]
+    end
+
+    options_for_select(container, selected)
+  end
+
+  def present(model, options = {})
+    klass = options.delete(:presenter_class) || "#{model.class}Presenter".constantize
+    presenter = klass.new(model, self, options)
+
+    yield(presenter) if block_given?
+
+    presenter
+  end
+end

test/dummy/app/helpers/fields_helper.rb

+# frozen_string_literal: true
+
+module FieldsHelper
+  def options_for_field_types(selected: nil)
+    options_for_select(Field.descendants.map { |klass| [klass.model_name.human, klass.to_s] }, selected)
+  end
+
+  def field_label(form, field_name:)
+    field_name = field_name.to_s.split(".").first.to_sym
+
+    form.fields.select do |field|
+      field.name == field_name
+    end.first&.label
+  end
+end

test/dummy/app/helpers/transitions_helper.rb

+# frozen_string_literal: true
+
+module TransitionsHelper
+  def options_for_transition_types(selected: nil)
+    options_for_select(Transition.descendants.map { |klass| [klass.model_name.human, klass.to_s] }, selected)
+  end
+end

test/dummy/app/jobs/application_job.rb

+# frozen_string_literal: true
+
+class ApplicationJob < ActiveJob::Base
+end

test/dummy/app/lib/bpmn/definition_container.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class DefinitionContainer
+    attr_reader :collection
+
+    def initialize(tokens)
+      @collection = tokens.map { |t| {t.id => t} }.reduce(&:merge!)
+      @start_id = tokens.first { |t| t.node_type == :start_event }.id
+    end
+
+    def start_event
+      @collection[@start_id]
+    end
+
+    def [](id)
+      @collection[id]
+    end
+
+    def slice(*ids)
+      @collection.slice(*ids).values
+    end
+
+    def self.parse(bpmn_xml)
+      tokens = Bpmn::Tokenizer.new.tokenize(bpmn_xml)
+      return nil unless tokens
+
+      new tokens
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokenizer.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokenizer
+    def tokenize(bpmn_xml)
+      return nil unless bpmn_xml.present?
+
+      doc = Nokogiri::XML(bpmn_xml) rescue nil
+      return nil unless doc && doc.errors.count.zero?
+
+      process = doc.at_xpath("//bpmn:process") rescue nil
+      return nil unless process
+
+      return unless process.present?
+      process.elements.map { |el| factory(el) }.compact
+    end
+
+    private
+
+    def factory(element)
+      case element.name
+      when "startEvent"
+        Bpmn::Tokens::StartEvent.new(element)
+      when "endEvent"
+        Bpmn::Tokens::EndEvent.new(element)
+      when "task"
+        Bpmn::Tokens::Task.new(element)
+      when "userTask"
+        Bpmn::Tokens::UserTask.new(element)
+      when "scriptTask"
+        Bpmn::Tokens::ScriptTask.new(element)
+      when "parallelGateway"
+        Bpmn::Tokens::ParallelGateway.new(element)
+      when "exclusiveGateway"
+        Bpmn::Tokens::ExclusiveGateway.new(element)
+      when "inclusiveGateway"
+        Bpmn::Tokens::InclusiveGateway.new(element)
+      when "sequenceFlow"
+        Bpmn::Tokens::SequenceFlow.new(element)
+      else
+        raise NotImplementedError.new("#{element.name} is unsupported yet.")
+      end
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/common_token.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::CommonToken < Bpmn::Tokens::Token
+    attr_reader :incoming_ids, :outgoing_ids
+
+    def initialize(element)
+      super
+
+      @incoming_ids = element.xpath("bpmn:incoming").map(&:content)
+      @outgoing_ids = element.xpath("bpmn:outgoing").map(&:content)
+    end
+
+    def to_hash
+      super.merge(
+        incoming_ids: incoming_ids,
+        outgoing_ids: outgoing_ids
+      )
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/end_event.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::EndEvent < Bpmn::Tokens::CommonToken
+    def event?
+      true
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/exclusive_gateway.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::ExclusiveGateway < Bpmn::Tokens::CommonToken
+    attr_reader :default_flow_id
+
+    def initialize(element)
+      super
+
+      @default_flow_id = element["default"]
+    end
+
+    def gateway?
+      true
+    end
+
+    def to_hash
+      super.merge(
+        default_flow_id: default_flow_id
+      )
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/extensions/condition_expression.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::Extensions::ConditionExpression
+    attr_reader :language, :condition, :type
+
+    def initialize(element)
+      @language = element["language"]
+      @condition = element.content
+      @type = element["xsi:type"]
+    end
+
+    def self.factory(xelement)
+      ce = xelement.at_xpath("bpmn:conditionExpression")
+      return nil unless ce
+      new(ce)
+    end
+
+    def to_hash
+      {
+        language: language,
+        condition: condition,
+        type: type,
+      }
+    end
+    alias_method :to_h, :to_hash
+  end
+end

test/dummy/app/lib/bpmn/tokens/inclusive_gateway.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::InclusiveGateway < Bpmn::Tokens::CommonToken
+    attr_reader :default_flow_id
+
+    def initialize(element)
+      super
+
+      @default_flow_id = element["default"]
+    end
+
+    def gateway?
+      true
+    end
+
+    def to_hash
+      super.merge(
+        default_flow_id: default_flow_id
+      )
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/parallel_gateway.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::ParallelGateway < Bpmn::Tokens::CommonToken
+    def gateway?
+      true
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/script_task.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::ScriptTask < Bpmn::Tokens::CommonToken
+    attr_reader :script_format, :script
+
+    def initialize(element)
+      super
+
+      @script_format = element["scriptFormat"]
+      @script = element.at_xpath("bpmn:script").try(:content)
+    end
+
+    def task?
+      true
+    end
+
+    def to_hash
+      super.merge(
+        extensions: {
+          script_format: script_format,
+          script: script
+        }
+      )
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/sequence_flow.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::SequenceFlow < Bpmn::Tokens::Token
+    attr_reader :source_id, :target_id
+    attr_reader :condition_expression
+
+    def initialize(element)
+      super
+
+      @source_id = element["sourceRef"]
+      @target_id = element["targetRef"]
+
+      @condition_expression = Bpmn::Tokens::Extensions::ConditionExpression.factory(element)
+    end
+
+    def flow?
+      true
+    end
+
+    def to_hash
+      super.merge(
+        source_id: source_id,
+        target_id: target_id,
+        extensions: {
+          condition_expression: condition_expression.to_hash
+        }
+      )
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/start_event.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::StartEvent < Bpmn::Tokens::CommonToken
+    def event?
+      true
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/task.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::Task < Bpmn::Tokens::CommonToken
+    def task?
+      true
+    end
+  end
+end

test/dummy/app/lib/bpmn/tokens/token.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::Token
+    attr_reader :id, :name, :node_type
+    attr_reader :documentation
+
+    def initialize(element)
+      # @element = element
+      @id = element["id"]
+      @name = element["name"] || ""
+      @node_type = element.name.underscore.to_sym
+
+      @documentation = element.at_xpath("bpmn:documentation")&.content || ""
+    end
+
+    def gateway?
+      false
+    end
+
+    def event?
+      false
+    end
+
+    def task?
+      false
+    end
+
+    def flow?
+      false
+    end
+
+    def to_hash
+      {
+        node_id: id,
+        node_type: node_type,
+        name: name
+      }
+    end
+    alias_method :to_h, :to_hash
+  end
+end

test/dummy/app/lib/bpmn/tokens/user_task.rb

+# frozen_string_literal: true
+
+module Bpmn
+  class Tokens::UserTask < Bpmn::Tokens::CommonToken
+    def task?
+      true
+    end
+  end
+end

test/dummy/app/mailers/application_mailer.rb

+# frozen_string_literal: true
+
+class ApplicationMailer < ActionMailer::Base
+  default from: "from@example.com"
+  layout "mailer"
+end

test/dummy/app/models/application_record.rb

+# frozen_string_literal: true
+
+class ApplicationRecord < ActiveRecord::Base
+  self.abstract_class = true
+
+  include ActsAsDefaultValue
+  include EnumAttributeLocalizable
+end

test/dummy/app/models/concerns/acts_as_default_value.rb

+# frozen_string_literal: true
+
+# https://github.com/FooBarWidget/default_value_for
+#
+# Copyright (c) 2008-2012 Phusion
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+module ActsAsDefaultValue
+  extend ActiveSupport::Concern
+
+  class NormalValueContainer
+    def initialize(value)
+      @value = value
+    end
+
+    def evaluate(_instance)
+      if @value.duplicable?
+        @value.dup
+      else
+        @value
+      end
+    end
+  end
+
+  class BlockValueContainer
+    def initialize(block)
+      @block = block
+    end
+
+    def evaluate(instance)
+      if @block.arity == 0
+        @block.call
+      else
+        @block.call(instance)
+      end
+    end
+  end
+
+  included do
+    after_initialize :set_default_values
+  end
+
+  def initialize(attributes = nil)
+    @initialization_attributes = attributes.is_a?(Hash) ? attributes.stringify_keys : {}
+    super
+  end
+
+  def set_default_values
+    self.class._all_default_attribute_values.each do |attribute, container|
+      next unless new_record? || self.class._all_default_attribute_values_not_allowing_nil.include?(attribute)
+
+      connection_default_value_defined = new_record? && respond_to?("#{attribute}_changed?") && !send("#{attribute}_changed?")
+
+      column = self.class.columns.detect { |c| c.name == attribute }
+      attribute_blank =
+        if column && column.type == :boolean
+          send(attribute).nil?
+        else
+          send(attribute).blank?
+        end
+      next unless connection_default_value_defined || attribute_blank
+
+      # allow explicitly setting nil through allow nil option
+      next if @initialization_attributes.is_a?(Hash) &&
+        (
+        @initialization_attributes.has_key?(attribute) ||
+          (
+          @initialization_attributes.has_key?("#{attribute}_attributes") &&
+            nested_attributes_options.stringify_keys[attribute]
+          )
+        ) &&
+        !self.class._all_default_attribute_values_not_allowing_nil.include?(attribute)
+
+      send("#{attribute}=", container.evaluate(self))
+
+      clear_attribute_changes [attribute] if has_attribute?(attribute)
+    end
+  end
+
+  def attributes_for_create(attribute_names)
+    attribute_names += self.class._all_default_attribute_values.keys.map(&:to_s).find_all do |name|
+      self.class.columns_hash.key?(name)
+    end
+
+    super
+  end
+
+  module ClassMethods
+    def _default_attribute_values # :nodoc:
+      @default_attribute_values ||= {}
+    end
+
+    def _default_attribute_values_not_allowing_nil # :nodoc:
+      @default_attribute_values_not_allowing_nil ||= Set.new
+    end
+
+    def _all_default_attribute_values # :nodoc:
+      if superclass.respond_to?(:_default_attribute_values)
+        superclass._all_default_attribute_values.merge(_default_attribute_values)
+      else
+        _default_attribute_values
+      end
+    end
+
+    def _all_default_attribute_values_not_allowing_nil # :nodoc:
+      if superclass.respond_to?(:_default_attribute_values_not_allowing_nil)
+        superclass._all_default_attribute_values_not_allowing_nil + _default_attribute_values_not_allowing_nil
+      else
+        _default_attribute_values_not_allowing_nil
+      end
+    end
+
+    # Declares a default value for the given attribute.
+    #
+    # Sets the default value to the given options parameter
+    #
+    # The <tt>options</tt> can be used to specify the following things:
+    # * <tt>allow_nil (default: true)</tt> - Sets explicitly passed nil values if option is set to true.
+    def default_value_for(attribute, value, **options)
+      allow_nil = options.fetch(:allow_nil, true)
+
+      container =
+        if value.is_a? Proc
+          BlockValueContainer.new(value)
+        else
+          NormalValueContainer.new(value)
+        end
+
+      _default_attribute_values[attribute.to_s] = container
+      _default_attribute_values_not_allowing_nil << attribute.to_s unless allow_nil
+
+      attribute
+    end
+  end
+end

test/dummy/app/models/concerns/enum_attribute_localizable.rb

+# frozen_string_literal: true
+
+module EnumAttributeLocalizable
+  extend ActiveSupport::Concern
+
+  module ClassMethods
+    def human_enum_value(attribute, value, options = {})
+      parts     = attribute.to_s.split(".")
+      attribute = parts.pop.pluralize
+      attributes_scope = "#{i18n_scope}.attributes"
+
+      if parts.any?
+        namespace = parts.join("/")
+        defaults = lookup_ancestors.map do |klass|
+          :"#{attributes_scope}.#{klass.model_name.i18n_key}/#{namespace}.#{attribute}.#{value}"
+        end
+        defaults << :"#{attributes_scope}.#{namespace}.#{attribute}.#{value}"
+      else
+        defaults = lookup_ancestors.map do |klass|
+          :"#{attributes_scope}.#{klass.model_name.i18n_key}.#{attribute}.#{value}"
+        end
+      end
+
+      defaults << :"attributes.#{attribute}.#{value}"
+      defaults << options.delete(:default) if options[:default]
+      defaults << value.to_s.humanize
+
+      options[:default] = defaults
+      I18n.translate(defaults.shift, options)
+    end
+  end
+end

test/dummy/app/models/concerns/fields/validations/acceptance.rb

+# frozen_string_literal: true
+
+module Concerns::Fields
+  module Validations::Acceptance
+    extend ActiveSupport::Concern
+
+    included do
+      attribute :acceptance, :boolean, default: false
+    end
+
+    def interpret_to(model, field_name, _accessibility, _options = {})
+      super
+      return unless acceptance
+
+      model.validates field_name, acceptance: true
+    end
+  end
+end

test/dummy/app/models/concerns/fields/validations/confirmation.rb

+# frozen_string_literal: true
+
+module Concerns::Fields
+  module Validations::Confirmation
+    extend ActiveSupport::Concern
+
+    included do
+      attribute :confirmation, :boolean, default: false
+    end
+
+    def interpret_to(model, field_name, _accessibility, _options = {})
+      super
+      return unless confirmation
+
+      model.validates field_name, confirmation: true
+    end
+  end
+end

test/dummy/app/models/concerns/fields/validations/exclusion.rb

+# frozen_string_literal: true
+
+module Concerns::Fields
+  module Validations::Exclusion
+    extend ActiveSupport::Concern
+
+    included do
+      embeds_one :exclusion, class_name: "Concerns::Fields::Validations::Exclusion::ExclusionOptions"
+      accepts_nested_attributes_for :exclusion
+
+      after_initialize do
+        build_exclusion unless exclusion
+      end
+    end
+
+    def interpret_to(model, field_name, accessibility, options = {})
+      super
+      exclusion&.interpret_to model, field_name, accessibility, options
+    end
+
+    class ExclusionOptions < FieldOptions
+      attribute :message, :string, default: ""
+      attribute :in, :string, default: [], array: true
+
+      def interpret_to(model, field_name, _accessibility, _options = {})
+        return if self.in.empty?
+
+        options = {in: self.in}
+        options[:message] = message if message.present?
+
+        model.validates field_name, exclusion: options, allow_blank: true
+      end
+    end
+  end
+end

test/dummy/app/models/concerns/fields/validations/format.rb

+# frozen_string_literal: true
+
+module Concerns::Fields
+  module Validations::Format
+    extend ActiveSupport::Concern
+
+    included do
+      embeds_one :format, class_name: "Concerns::Fields::Validations::Format::FormatOptions"
+      accepts_nested_attributes_for :format
+
+      after_initialize do
+        build_format unless format
+      end
+    end
+
+    def interpret_to(model, field_name, accessibility, options = {})
+      super
+      format&.interpret_to model, field_name, accessibility, options
+    end
+
+    class FormatOptions < FieldOptions
+      attribute :with, :string, default: ""
+      attribute :message, :string, default: ""
+
+      validate do
+        begin
+          Regexp.new(with) if with.present?
+        rescue RegexpError
+          errors.add :with, :invalid
+        end
+      end
+
+      def interpret_to(model, field_name, _accessibility, _options = {})
+        return if with.blank?
+
+        with = Regexp.new(self.with)
+
+        options = {with: with}
+        options[:message] = message if message.present?
+
+        model.validates field_name, format: options, allow_blank: true
+      end
+    end
+  end
+end

test/dummy/app/models/concerns/fields/validations/inclusion.rb

+# frozen_string_literal: true
+
+module Concerns::Fields
+  module Validations::Inclusion
+    extend ActiveSupport::Concern
+
+    included do
+      embeds_one :inclusion, class_name: "Concerns::Fields::Validations::Inclusion::InclusionOptions"
+      accepts_nested_attributes_for :inclusion
+
+      after_initialize do
+        build_inclusion unless inclusion
+      end
+    end
+
+    def interpret_to(model, field_name, accessibility, options = {})
+      super
+      inclusion&.interpret_to model, field_name, accessibility, options
+    end
+
+    class InclusionOptions < FieldOptions
+      attribute :message, :string, default: ""
+      attribute :in, :string, default: [], array: true
+
+      def interpret_to(model, field_name, _accessibility, _options = {})
+        return if self.in.empty?
+
+        options = {in: self.in}
+        options[:message] = message if message.present?
+
+        model.validates field_name, inclusion: options, allow_blank: true
+      end
+    end
+  end
+end

test/dummy/app/models/concerns/fields/validations/length.rb

+# frozen_string_literal: true
+
+module Concerns::Fields
+  module Validations::Length
+    extend ActiveSupport::Concern
+
+    included do
+      embeds_one :length, class_name: "Concerns::Fields::Validations::Length::LengthOptions"
+      accepts_nested_attributes_for :length
+
+      after_initialize do
+        build_length unless length
+      end
+    end
+
+    def interpret_to(model, field_name, accessibility, options = {})
+      super
+      length&.interpret_to model, field_name, accessibility, options
+    end
+
+    class LengthOptions < FieldOptions
+      attribute :minimum, :integer, default: 0
+      attribute :maximum, :integer, default: 0
+      attribute :is, :integer, default: 0
+
+      validates :minimum, :maximum, :is,
+                numericality: {
+                  greater_than_or_equal_to: 0
+                }
+      validates :maximum,
+                numericality: {
+                  greater_than: :minimum
+                },
+                if: proc { |record| record.maximum <= record.minimum && record.maximum.positive? }
+
+      validates :is,
+                numericality: {
+                  equal_to: 0
+                },
+                if: proc { |record| !record.maximum.zero? || !record.minimum.zero? }
+
+      def interpret_to(model, field_name, _accessibility, _options = {})
+        return if self.minimum.zero? && self.maximum.zero? && self.is.zero?
+
+        if is.positive?
+          model.validates field_name, length: {is: is}, allow_blank: true
+          return
+        end
+
+        options = {}
+        options[:minimum] = minimum if minimum.positive?
+        options[:maximum] = maximum if maximum.positive?
+        return if options.empty?
+
+        model.validates field_name, length: options, allow_blank: true
+      end
+    end
+  end
+end

test/dummy/app/models/concerns/fields/validations/numericality.rb

+# frozen_string_literal: true
+
+module Concerns::Fields
+  module Validations::Numericality
+    extend ActiveSupport::Concern
+
+    included do
+      embeds_one :numericality, class_name: "Concerns::Fields::Validations::Numericality::NumericalityOptions"
+      accepts_nested_attributes_for :numericality
+
+      after_initialize do
+        build_numericality unless numericality
+      end
+    end
+
+    def interpret_to(model, field_name, accessibility, options = {})
+      super
+      numericality&.interpret_to model, field_name, accessibility, options
+    end
+
+    class NumericalityOptions < FieldOptions
+      attribute :lower_bound_check, :string, default: "disabled"
+      attribute :upper_bound_check, :string, default: "disabled"
+
+      attribute :lower_bound_value, :float, default: 0.0
+      attribute :upper_bound_value, :float, default: 0.0
+
+      enum lower_bound_check: {
+        disabled: "disabled",
+        greater_than: "greater_than",
+        greater_than_or_equal_to: "greater_than_or_equal_to"
+      }, _prefix: :lower_bound_check
+      enum upper_bound_check: {
+        disabled: "disabled",
+        less_than: "less_than",
+        less_than_or_equal_to: "less_than_or_equal_to"
+      }, _prefix: :upper_bound_check
+
+      validates :upper_bound_value,
+                numericality: {
+                  greater_than: :lower_bound_value
+                },
+                if: proc { upper_bound_check != "disabled" && lower_bound_check != "disabled" }
+
+      def interpret_to(model, field_name, _accessibility, _options = {})
+        options = {}
+        options[lower_bound_check] = lower_bound_value unless lower_bound_check_disabled?
+        options[upper_bound_check] = upper_bound_value unless upper_bound_check_disabled?
+        return if options.empty?
+
+        options.symbolize_keys!
+        model.validates field_name, numericality: options, allow_blank: true
+      end
+    end
+  end
+end

test/dummy/app/models/concerns/fields/validations/presence.rb

+# frozen_string_literal: true
+
+module Concerns::Fields
+  module Validations::Presence
+    extend ActiveSupport::Concern
+
+    included do
+      attribute :presence, :boolean, default: false
+    end
+
+    def interpret_to(model, field_name, _accessibility, _options = {})
+      super
+      return unless presence
+
+      model.validates field_name, presence: true
+    end
+  end
+end

test/dummy/app/models/concerns/form_core/acts_as_default_value.rb

+# frozen_string_literal: true
+
+# https://github.com/FooBarWidget/default_value_for
+#
+# Copyright (c) 2008-2012 Phusion
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+module FormCore
+  module ActsAsDefaultValue
+    extend ActiveSupport::Concern
+
+    class NormalValueContainer
+      def initialize(value)
+        @value = value
+      end
+
+      def evaluate(_instance)
+        if @value.duplicable?
+          @value.dup
+        else
+          @value
+        end
+      end
+    end
+
+    class BlockValueContainer
+      def initialize(block)
+        @block = block
+      end
+
+      def evaluate(instance)
+        if @block.arity == 0
+          @block.call
+        else
+          @block.call(instance)
+        end
+      end
+    end
+
+    included do
+      after_initialize :set_default_values
+    end
+
+    def initialize(attributes = nil)
+      @initialization_attributes = attributes.is_a?(Hash) ? attributes.stringify_keys : {}
+      super
+    end
+
+    def set_default_values
+      self.class._all_default_attribute_values.each do |attribute, container|
+        next unless new_record? || self.class._all_default_attribute_values_not_allowing_nil.include?(attribute)
+
+        attribute_blank =
+          if self.class.attribute_types[attribute]&.type == :boolean
+            send(attribute).nil?
+          else
+            send(attribute).blank?
+          end
+        next unless attribute_blank
+
+        # allow explicitly setting nil through allow nil option
+        next if @initialization_attributes.is_a?(Hash) &&
+          (
+          @initialization_attributes.has_key?(attribute) ||
+            (
+            @initialization_attributes.has_key?("#{attribute}_attributes") &&
+              nested_attributes_options.stringify_keys[attribute]
+            )
+          ) &&
+          !self.class._all_default_attribute_values_not_allowing_nil.include?(attribute)
+
+        send("#{attribute}=", container.evaluate(self))
+
+        clear_attribute_changes [attribute] if has_attribute?(attribute)
+      end
+    end
+
+    module ClassMethods
+      def _default_attribute_values # :nodoc:
+        @default_attribute_values ||= {}
+      end
+
+      def _default_attribute_values_not_allowing_nil # :nodoc:
+        @default_attribute_values_not_allowing_nil ||= Set.new
+      end
+
+      def _all_default_attribute_values # :nodoc:
+        if superclass.respond_to?(:_default_attribute_values)
+          superclass._all_default_attribute_values.merge(_default_attribute_values)
+        else
+          _default_attribute_values
+        end
+      end
+
+      def _all_default_attribute_values_not_allowing_nil # :nodoc:
+        if superclass.respond_to?(:_default_attribute_values_not_allowing_nil)
+          superclass._all_default_attribute_values_not_allowing_nil + _default_attribute_values_not_allowing_nil
+        else
+          _default_attribute_values_not_allowing_nil
+        end
+      end
+
+      # Declares a default value for the given attribute.
+      #
+      # Sets the default value to the given options parameter
+      #
+      # The <tt>options</tt> can be used to specify the following things:
+      # * <tt>allow_nil (default: true)</tt> - Sets explicitly passed nil values if option is set to true.
+      def default_value_for(attribute, value, **options)
+        allow_nil = options.fetch(:allow_nil, true)
+
+        container =
+          if value.is_a? Proc
+            BlockValueContainer.new(value)
+          else
+            NormalValueContainer.new(value)
+          end
+
+        _default_attribute_values[attribute.to_s] = container
+        _default_attribute_values_not_allowing_nil << attribute.to_s unless allow_nil
+
+        attribute
+      end
+    end
+  end
+end

test/dummy/app/models/field.rb

+# frozen_string_literal: true
+
+class Field < ApplicationRecord
+  include FormCore::Concerns::Models::Field
+
+  self.table_name = "fields"
+
+  belongs_to :form, class_name: "Form", foreign_key: "form_id", touch: true
+
+  validates :label,
+            presence: true
+  validates :type,
+            inclusion: {
+              in: ->(_) { Field.descendants.map(&:to_s) }
+            },
+            allow_blank: false
+
+  default_value_for :name,
+                    -> (_) { "field_#{SecureRandom.hex(3)}" },
+                    allow_nil: false
+
+  def self.type_key
+    model_name.name.split("::").last.underscore
+  end
+
+  def type_key
+    self.class.type_key
+  end
+
+  def options_configurable?
+    options.is_a?(FieldOptions) && options.attributes.any?
+  end
+
+  def validations_configurable?
+    validations.is_a?(FieldOptions) && validations.attributes.any?
+  end
+
+  def attach_choices?
+    false
+  end
+
+  protected
+
+  def interpret_validations_to(model, accessibility, overrides = {})
+    return unless accessibility == :read_and_write
+
+    validations_overrides = overrides.fetch(:validations) { {} }
+    validations =
+      if validations_overrides.any?
+        self.validations.dup.update(validations_overrides)
+      else
+        self.validations
+      end
+
+    validations.interpret_to(model, name, accessibility)
+  end
+
+  def interpret_extra_to(model, accessibility, overrides = {})
+    options_overrides = overrides.fetch(:options) { {} }
+    options =
+      if options_overrides.any?
+        self.options.dup.update(options_overrides)
+      else
+        self.options
+      end
+
+    options.interpret_to(model, name, accessibility)
+  end
+end
+
+require_dependency "fields"

test/dummy/app/models/field_options.rb

+# frozen_string_literal: true
+
+class FieldOptions < DuckRecord::Base
+  include FormCore::ActsAsDefaultValue
+  include EnumAttributeLocalizable
+
+  class_attribute :keeping_old_serialization
+
+  attr_accessor :raw_attributes
+
+  def interpret_to(_model, _field_name, _accessibility, _options = {})
+  end
+
+  def serializable_hash(options = {})
+    options = (options || {}).reverse_merge include: self.class._embeds_reflections.keys
+    super options
+  end
+
+  private
+
+  def _assign_attribute(k, v)
+    return unless respond_to?("#{k}=")
+    public_send("#{k}=", v)
+  end
+
+  class << self
+    def _embeds_reflections
+      _reflections.select { |_, v| v.is_a? DuckRecord::Reflection::EmbedsAssociationReflection }
+    end
+
+    def model_version
+      1
+    end
+
+    def root_key_for_serialization
+      "#{self}.#{model_version}"
+    end
+
+    def dump(obj)
+      return YAML.dump({}) unless obj
+
+      serializable_hash =
+        if obj.respond_to?(:serializable_hash)
+          obj.serializable_hash
+        elsif obj.respond_to?(:to_hash)
+          obj.to_hash
+        else
+          raise ArgumentError, "`obj` required can be cast to `Hash` -- #{obj.class}"
+        end.stringify_keys
+
+      data = {root_key_for_serialization => serializable_hash}
+      if keeping_old_serialization
+        data.reverse_merge! obj.raw_attributes
+      end
+
+      YAML.dump(data)
+    end
+
+    def load(yaml_or_hash)
+      case yaml_or_hash
+      when Hash
+        load_from_hash(yaml_or_hash)
+      when String
+        load_from_yaml(yaml_or_hash)
+      else
+        new
+      end
+    end
+
+    WHITELIST_CLASSES = [BigDecimal, Date, Time, Symbol]
+    def load_from_yaml(yaml)
+      return new if yaml.blank?
+
+      unless yaml.is_a?(String) && /^---/.match?(yaml)
+        return new
+      end
+
+      decoded = YAML.safe_load(yaml, WHITELIST_CLASSES)
+      unless decoded.is_a? Hash
+        return new
+      end
+
+      record = new decoded[root_key_for_serialization]
+      record.raw_attributes = decoded.freeze
+      record
+    end
+
+    def load_from_hash(hash)
+      return new if hash.blank?
+      record = new hash[root_key_for_serialization]
+      record.raw_attributes = hash.freeze
+      record
+    end
+  end
+end

test/dummy/app/models/fields.rb

+# frozen_string_literal: true
+
+module Fields
+  %w[
+  text boolean decimal integer
+  ].each do |type|
+    require_dependency "fields/#{type}_field"
+  end
+end

test/dummy/app/models/fields/boolean_field.rb

+# frozen_string_literal: true
+
+module Fields
+  class BooleanField < Field
+    serialize :validations, Validations::BooleanField
+    serialize :options, Options::BooleanField
+
+    def stored_type
+      :boolean
+    end
+  end
+end

test/dummy/app/models/fields/decimal_field.rb

+# frozen_string_literal: true
+
+module Fields
+  class DecimalField < Field
+    serialize :validations, Validations::DecimalField
+    serialize :options, Options::DecimalField
+
+    def stored_type
+      :decimal
+    end
+  end
+end

test/dummy/app/models/fields/integer_field.rb

+# frozen_string_literal: true
+
+module Fields
+  class IntegerField < Field
+    serialize :validations, Validations::IntegerField
+    serialize :options, Options::IntegerField
+
+    def stored_type
+      :integer
+    end
+
+    protected
+
+    def interpret_extra_to(model, accessibility, _overrides = {})
+      return if accessibility != :read_and_write
+
+      model.validates name, numericality: {only_integer: true}, allow_blank: true
+    end
+  end
+end

test/dummy/app/models/fields/options/boolean_field.rb

+# frozen_string_literal: true
+
+module Fields::Options
+  class BooleanField < FieldOptions
+  end
+end

test/dummy/app/models/fields/options/decimal_field.rb

+# frozen_string_literal: true
+
+module Fields::Options
+  class DecimalField < FieldOptions
+    attribute :step, :decimal, default: 0.01
+
+    validates :step,
+              numericality: {
+                greater_than_or_equal_to: 0.0
+              }
+  end
+end