This tutorial covers various tasks that can be accomplished with the workflow service — a simple workflow, adding a task, rolling back a task, and completing a task.
These steps describe the procedure in Procedure 11.1, Creating a Simple Workflow. The procedure covers creating a hello world workflow and describing the task state change.
Design a workflow by defining the desired tasks and the dependencies between them.
Create a new named task class for the different task types. Be sure to define the BASE_DATA_OBJECT_TYPE, the getBaseDataObjectType, constructors, and clone methods. Also include the methods to invoke.
Write the PDL file to support the new task type.
Create an instantiator for DomainObjectFactory.
Create a workflow template based on the design.
Instantiate a workflow from a workflow template.
Call the workflow start method to start the Engine.
Design your workflow.
Create a new task type by subclassing task:
public class HelloWorldTask extends Task {
//The base data object is used for the domain object
public static final String BASE_DATA_OBJECT_TYPE =
"com.arsdigita.workflow.simple.HelloWorldTask";
protected String getBaseDataObjectType() {
return BASE_DATA_OBJECT_TYPE;
}
//constructors are not inherited from subclasses
//so you'll need to add them
public HelloWorldTask(String label, String description) {
this(BASE_DATA_OBJECT_TYPE);
initAttributes(label,description);
}
public HelloWorldTask(DataObject taskDataObject) {
super(taskDataObject);
}
public HelloWorldTask() {
this(BASE_DATA_OBJECT_TYPE);
setState(DISABLED);
}
public HelloWorldTask(OID oid) throws
DataObjectNotFoundException {
super(oid);
}
public HelloWorldTask(BigDecimal id) throws
DataObjectNotFoundException {
this(new OID(BASE_DATA_OBJECT_TYPE, id));
}
protected HelloWorldTask(ObjectType type) {
super(type);
}
protected HelloWorldTask(String typeName) {
super(typeName);
}
// Add functionality in these methods
public void enableEvt() {
System.out.println(getLabel()+": I am enabled");
}
public void disableEvt() {
System.out.println(getLabel()+": I have been disabled");
}
public void finishEvt() {
System.out.println(getLabel()+": I am finished");
}
public void rollbackEvt() {
System.out.println(getLabel()+": I was rollbacked");
}
//Write clone functionality. Note the use of copyAttributes
//
public Object clone() {
HelloWorldTask taskClone = new HelloWorldTask();
copyAttributes(taskClone);
return taskClone;
}
//Add this method because future versions will
protected void copyAttributes(HelloWorldTask taskClone) {
taskClone.setLabel(getLabel());
taskClone.setDescription(getDescription());
taskClone.setActive(isActive());
}
} |
Ensure that the constructors, events, and clone methods are coded for the new task type.
Write the PDL for the new subclass of task. This is a simple case; you would probably have additional tables for select and DML statements.
object type HelloWorldTask extends Task {
retrieve {
super;
}
insert {
super;
}
update {
super;
}
delete {
super;
}
} |
In your package initializer section, create and add a new instantiator.
DomainObjectInstantiator instHelloWorldTask =
new ACSObjectInstantiator() {
public DomainObject doNewInstance(DataObject
dataObject) {
return new HelloWorldTask(dataObject);
}
};
DomainObjectFactory.registerInstantiator(
"com.arsdigita.workflow.simple.",
instHelloWorldTask); |
Create the workflow template.
public class WFTutorialHello {
public void WFTutorialHello() {
HelloWorldTask helloTask1 =
new HelloWorldTask("hello 1", "description");
HelloWorldTask helloTask2 =
new HelloWorldTask("hello 2", "description");
//Note(1): Save the task before adding the dependency
helloTask1.save();
helloTask2.save();
helloTask2.addDependency(helloTask1);
helloTask2.save();
User user = new User(__USER_ID__)
Workflow wf = new Workflow("hello example",
"tutorial example of creating a task");
wf.addTask(helloTask1);
wf.addTask(helloTask2);
//Note(2): The workflow mad
helloTask1.save();
helloTask2.save();
wf.start();
helloTask1.finish();
helloTask2.finish();
}
} |
To add a task, you call the addTask method in workflow. The task is inactive when created, and can be set to be active by calling the setActive(true). A task is not considered part of the workflow until it becomes active. Tasks are created in an inactive state to allow you to preview them before altering the workflow state.
Once a task is active, it can affect the workflow and other dependent tasks. Manually setting the task state is required only when adding a new task to an in-progress workflow. When the workflow is started, it will automatically set all tasks as active.