jBPM Tools Reference Guide

Clicking the Next button brings us to the wizard page where the name and location for the project are specified. We choose, for example, HellojBPM as the name and accept the default location.

The project will be created in the workspace root directory by default. If you want to change the directory for your future project, deselect Use default location and click the Browse... button to set desired location, or simply enter the location manually.

On the next screen you will be prompted to select the core jBPM location that we have defined in the previous chapter.

Clicking on the Finish button results in the project being generated. The wizard creates four source folders: one for the processes (src/main/jpdl), one for the java sources (src/main/java), one for the unit tests (src/test/java) and one for the resources such as the jbpm.properties and the hibernate.properties files (src/main/config). In addition a classpath container with all the core jBPM libraries is added to the project

Selecting the JBoss jBPM category, then the jBPM Process Definition item and clicking on the Next button brings us to the Create Process Definition page.

We choose hello as the name of the process archive file. Click on the Finish button to end the wizard and open the process definition editor.

You can see in the Package Explorer that creating a process definition involves creating an XML file called [process name].jpdl.xml, which contains the process definition information. A JPG file called [process name].jpg will also be automatically generated when changes are saved to the process.

Notice that two first gaps have been filled automatically. Here, instead of the Package option, the Enclose type option can be selected to define the type in which the new class should be created will be enclosed.

In our case, we leave everything as it is, just type HelloActionHandler as a name of new class and add org.jbpm.graph.ActionHendler interface as it is shown in the picture above.

Thus, our HelloActionHandler implements the ActionHandler interface, including the execute method as shown in the next figure. Here, we add a variable named greeting to the collection of process variables and put a message in it: "Hello from ActionHandler".

Now, as we have HelloActionHandler class defined, let's explore how we can handle it.

Populate the new class with the following code:

package com.jbay;

import org.jbpm.graph.def.ProcessDefinition;
import org.jbpm.graph.exe.ProcessInstance;

import junit.framework.TestCase;

public class HelloTest extends TestCase
{
	public void testActionhandler() throws Exception {
		
		ProcessDefinition definition = 
			ProcessDefinition.parseXmlResource("hello.jpdl.xml");
		
		ProcessInstance instance = new ProcessInstance(definition);
		assertNull("The greeting variable should not exist",
				instance.getContextInstance().getVariable("greeting"));
		
		instance.signal();
		assertEquals("The greeting variable is created",
				instance.getContextInstance().getVariable("greeting"),
				"Hello from ActionHandler");
	}
}				

We assert that no variable called greeting exist. Then we give the process a signal to move it to the action state. We want to associate the execution of the action with the event of going over the transition from the start state to the action state. So after the signal, the process should be in the action state as in the previous scenario. But moreover, the greeting variable should exist and contain the string "Hello from ActionHandler". That is what we assert in the last lines of the test method.

Running the tests now results in a failure. The point is that we did not associate the action with any particular event in the process definition, so the process variable did not get set.

Let's do something about it and add an action to the first transition of our sample process. To do this you can use the Actions tab in the Properties Editor that is under the graphical canvas. Bring up the popup menu of the action element container and chose New Action as it's shown on the figure below. The other way to add an action to the transition is simply to use the dropdown menu that is available under the action icon in the right upper corner of the Properties View.

After adding the action a tabbed view with three pages will appear.

The first of these three pages allows you to give the Action a name. The last page contains some advanced attributes such as whether the Action is asynchronous. The Details page is the most important. It allows to choose and configure the actual action handler implementation.

Clicking on the Search... button brings us to a Choose Class dialog.

We choose our previously created HelloActionHandler class and click the OK button. After selecting the action handler for the action, we can run the test and observe it gives us a green light.

There we are. The above objective has been achieved.

We should choose the Task tab and then bring up the context menu or click the button in the top right corner of the view to add a Task to our Task node.

Every added Task has its own configuration possibilities. You can access them through the Properties view as well.

The General page is a place where you can specify the name of a Task and its description. For instance, let it be approve oder with appropriate description that you can see in the figure below.

Now, look at Details page. First, you should specify the due date that is a mandatory property for the Task. The due date is the date on which the task should be accomplished. Here you can also set a Task priority as well as signaling, notifying or blocking. The Blocking attribute indicates that the process will not be able to continue if this task is still unaccomplished. The Generate Form... button is for creating a simple task form that can be rendered by the jBPM console.

For our example, we specify the due date as 2 business days, choose the high priority and also check the Signaling and Notify attributes. It means that the Task should be accomplished in 2 business days and the assignee will be notified by email when the task is assigned. To specify how the Task should be assigned switch on to the Assignment page.

On the Reminder page you can specify whether the assignee will be reminded of the task that awaits him.

In our case, the assignee will be reminded by email after two business hours and continue to get reminding every business hour after that.

In the next figure you can see our configuring generated into XML.

It consists of several pages:

It includes the next options to adjust: