PR-241 Defining workflow dynamically from JSON

README.adoc

@@ -494,6 +494,12 @@ The workflow library itself uses this feature to tweak the graphical
 representation of the workflow. See below.
 
 
+### Defining workflow dynamically from JSON
+
+For an advance example please see
+link:https://github.com/geekq/workflow/blob/develop/test/workflow_from_json_test.rb[workflow_from_json_test.rb].
+
+
 ### Compose workflow definition with `include`
 
 In case you have very extensive workflow definition or would like to reuse
@@ -525,6 +531,7 @@ Changelog
 
 * link:https://github.com/geekq/workflow/pull/227[#227] Allow event arguments to be taken into account when selecting the event
 * link:https://github.com/geekq/workflow/pull/232[#232] Add ability to include partial workflow definitions for composability
+* link:https://github.com/geekq/workflow/pull/241[#241] Example for defining workflow dynamically from JSON
 
 === New in the version 3.0.0
 

test/workflow_from_json_test.rb

@@ -0,0 +1,158 @@
+require File.join(File.dirname(__FILE__), 'test_helper')
+require 'workflow'
+class WorkflowFromJsonTest < Minitest::Test
+
+  test '#241 define a workflow from JSON' do
+    c = Class.new
+    c.class_eval do
+      include Workflow
+
+      attr_reader :events
+
+      def record(event)
+        @events ||= []
+        @events << event
+      end
+
+      def ran?(event)
+        @events.include? event
+      end
+
+      def clear_events
+        @events = []
+      end
+
+      def event_1(test)
+        # puts "running event_1 with arg '#{test}'"
+        record __method__
+      end
+
+      def before_transition(from, to, triggering_event, *args, **kwargs)
+        # puts "before_transition #{from} -> #{to}, #{triggering_event}, #{args}, #{kwargs}"
+        record __method__
+      end
+
+      def on_transition(from, to, triggering_event, *args, **kwargs)
+        # puts "on_transition #{from} -> #{to}, #{triggering_event}, #{args}, #{kwargs}"
+        record __method__
+      end
+
+      def after_transition(from, to, triggering_event, *args, **kwargs)
+        # puts "after_transition #{from} -> #{to}, #{triggering_event}, #{args}, #{kwargs}"
+        record __method__
+      end
+
+      def event_1_condition?
+        # puts "event_1_condition? -> true"
+        record __method__
+        true
+      end
+
+      def on_state_1_exit(new_state, event, *args)
+        # puts "on_state_1_exit(#{new_state}, #{event}, #{args})"
+        record __method__
+      end
+
+      def entering_state_2(prior_state, triggering_event, *args, **kwargs)
+        # puts "entering_state_2 #{prior_state}, #{triggering_event}, #{args}, #{kwargs}"
+        record __method__
+      end
+
+      def entering_state_3(prior_state, triggering_event, *args, **kwargs)
+        # puts "entering_state_3 #{prior_state}, #{triggering_event}, #{args}, #{kwargs}"
+        record __method__
+      end
+
+      def on_state_2_entry(new_state, event, *args)
+        # puts "on_state_2_entry(#{new_state}, #{event}, #{args})"
+        record __method__
+      end
+
+    end
+
+    ran_normal = []
+    hash = {
+      state_1: {
+        events: {
+          event_1: {
+            transition_to: :state_2,
+            if: :event_1_condition?,
+            meta: { e1: 1 }
+          },
+        },
+        meta: { a: 1 }
+      },
+      state_2: {
+        events: {
+          event_2: {
+            transition_to: :state_3,
+          }
+        },
+        on_entry: :entering_state_2,
+        meta: { a: 2 }
+      },
+      state_3: {
+        on_entry: "entering_state_3",
+      }
+    }
+
+    spec = Workflow::Specification.new do
+
+      hash.each_pair do |state_name, state_def|
+
+        state state_name, state_def
+
+        on_entry {|prior_state, triggering_event| send state_def[:on_entry], prior_state, triggering_event } if state_def.include?(:on_entry)
+        on_exit { ran_normal << :on_exit }
+
+        state_def[:events]&.each_pair do |event_name, event_def|
+          event event_name, event_def
+        end
+
+      end
+
+      before_transition do |from, to, triggering_event, *args, **kwargs|
+        ran_normal << :before_transition
+        before_transition(from, to, triggering_event, *args, **kwargs)
+      end
+
+      on_transition do |from, to, triggering_event, *args, **kwargs|
+        ran_normal << :on_transition
+        on_transition(from, to, triggering_event, *args, **kwargs)
+      end
+
+      after_transition do |from, to, triggering_event, *args, **kwargs|
+        ran_normal << :after_transition
+        after_transition(from, to, triggering_event, *args, **kwargs)
+      end
+
+    end
+
+    c.send :assign_workflow, spec
+
+    o = c.new
+
+    assert o.state_1?, "Should be state_1"
+    refute o.state_2?, "Should not be state_2"
+
+    o.event_1! "hello"
+    [:event_1_condition?, :event_1, :entering_state_2, :before_transition, :on_transition, :after_transition].each do |event|
+      assert o.ran?(event), "Should have run event #{event}"
+    end
+
+    refute o.state_1?, "Should not be state_1"
+    assert o.state_2?, "Should be state_2"
+
+    o.clear_events
+    o.event_2!
+    refute o.ran?(:event_1), "Should not have run event_1"
+    [:entering_state_3, :before_transition, :on_transition, :after_transition].each do |event|
+      assert o.ran?(event), "Should have run event #{event}"
+    end
+
+    assert ran_normal.include?(:before_transition), "Should have run before_transition proc"
+    assert ran_normal.include?(:on_transition), "Should have run on_transition proc"
+    assert ran_normal.include?(:after_transition), "Should have run after_transition proc"
+    assert ran_normal.include?(:on_exit), "Should have run on_exit proc"
+  end
+end