Page History

...

Here is an example of performing joins using collections of child workflows

...

Join conditions

In workflows you often want to fork parallel steps and then join on certain events. You often have complex logic to decide on what the join condition is. e.g. in pseudo code code

...

In BeanFlow we implement join conditions using regular Java code. The basic idea is that a Activity will listen to changes in a number of different State objects such as fields a, b and c. You can then write an activity bean to perform the join condition you need. When the condition is met you can then perform whatever logic you wish such as

...

Here is an example activity implemented in Java code for the above code.

...

...

Building workflows

So we've been over the basics of activities and showed how we can perform joins along with compose them. Remember they are just Java bean so you can implement them however you wish.

...

There now follows a simple workflow example...

...

...

As you can see the step is defined by an enumeration Step and we have a regular Java method to implement each step. The step method can then return the step to go to next after the current method terminates. If you return null or use a void method then the workflow suspends.

...

• suspending workflows (such as when they wait for external events such as user input or an asynchronous message to arrive)
• looping & using predicates
• forking and joining child activities
• declaratively moving from one step to another

...

...

In the above example, each workflow step is implemented as a method. If the method returns a String it is interpreted as the next step which will be executed. Returning null (or using a void return type) will suspend the workflow.

...

To avoid typos between the workflow step enum and the methods in the workflow class, on startup we check that there are suitable methods available for the enum. Many thanks to Sam for this idea! e.g. the following bad workflow is automatically caught and a useful error is generated.

...

...