added drop method to baton to cancel workflow execution

README.rdoc

@@ -152,6 +152,19 @@ at the same time.
     jWorkflow.order([man, man, halfMan])
              .andThen([jWorkflow.order([guy, guy]).andThen(girl), pizzaPlace]);
 
+=Canceling Workflows
+
+To cancel the execution of the workflow you can call the drop method on the baton:
+
+    function (previous, baton) {
+        //the value passed to drop will be passed onto the final callback if it exists
+        baton.drop("I dropped the soap");
+        //this value will NOT be passed to the next workflow step
+        return 10;
+    }
+
+NOTE: This will force the workflow into async mode.
+
 =Contributers:
 
     Gord Tanner <gord@tinyhippos.com>

Rakefile

@@ -7,6 +7,6 @@ desc "Use the Closure Compiler to compress jWorkflow.js"
 task :build do
   js  = File.open('lib/jWorkflow.js', 'r')
   min = Closure::Compiler.new.compile(js)
-  File.open('jworkflow-min-0.6.0.js', 'w') {|f| f.write(min) }
+  File.open('jworkflow-min-0.7.0.js', 'w') {|f| f.write(min) }
 end
 

lib/jWorkflow.js

@@ -49,6 +49,14 @@ var jWorkflow = (function () {
                                     _callback.func.apply(_callback.context, [result]);
                                 }
                             }
+                        },
+
+                        drop: function (result) {
+                            _taken = true;
+                            _tasks = [];
+                            setTimeout(function () {
+                                _baton.pass(result);
+                            }, 1);
                         }
                     };
                 }()),

package.json

@@ -1,6 +1,6 @@
 {
   "name": "jWorkflow",
-  "version" : "0.6.0",
+  "version" : "0.7.0",
   "description" : "dude, wheres my workflow?",
   "homepage": "https://github.com/tinyhippos/jWorkflow",
   "author": "gtanner",

test/test_jworkflow.js

@@ -488,4 +488,34 @@ $(document).ready(function () {
                      equals(x, "sweeet");
                  });
     });
+
+    asyncTest("jWorkflow, we can stop execution of a workflow with baton.drop", function () {
+        expect(2);
+
+        var inc = function (prev, baton) {
+                if (prev >= 3) {
+                    baton.drop(prev);
+                }
+                return ++prev;
+            },
+            protected = false;
+
+        jWorkflow.order(inc)
+                 .andThen(inc)
+                 .andThen(inc)
+                 .andThen(inc)
+                 .andThen(inc)
+                 .andThen(inc)
+                 .andThen(function (prev) {
+                     protected = true;
+                     return prev;
+                 }).start({
+                     initialValue: 0,
+                     callback: function (result) {
+                         start();
+                         equals(protected, false);
+                         equals(result, 3);
+                     }
+                 });
+    });
 });