Chapter 3. Work item handler project customization

You can customize the code of a work item handler project. There are two Java methods required by a work item handler, executeWorkItem and abortWorkItem.

Table 3.1. Java method descriptions

Java MethodDescription

executeWorkItem(WorkItem workItem, WorkItemManager manager)

Executed by default when the work item handler is run.

abortWorkItem(WorkItem workItem, WorkItemManager manager)

Executed when the work item is aborted.

In both methods, the WorkItem parameter contains any of the parameters entered into the custom task through a GUI or API call, and the WorkItemManager parameter is responsible for tracking the state of the custom task.

Example code structure

public class MyWorkItemWorkItemHandler extends AbstractLogOrThrowWorkItemHandler {

  public void executeWorkItem(WorkItem workItem, WorkItemManager manager) {
    try {
      RequiredParameterValidator.validate(this.getClass(), workItem);

      // sample parameters
      String sampleParam = (String) workItem.getParameter("SampleParam");
      String sampleParamTwo = (String) workItem.getParameter("SampleParamTwo");

      // complete workitem impl...

      // return results
      String sampleResult = "sample result";
      Map<String, Object> results = new HashMap<String, Object>();
      results.put("SampleResult", sampleResult);
      manager.completeWorkItem(workItem.getId(), results);
    } catch(Throwable cause) {
      handleException(cause);
    }
	}

	@Override
	public void abortWorkItem(WorkItem workItem, WorkItemManager manager) {
    // similar
	}
}

Table 3.2. Parameter descriptions

ParameterDescription

RequiredParameterValidator.validate(this.getClass(), workItem);

Checks that all parameters marked “required” are present. If they are not, an IllegalArgumentException is thrown.

String sampleParam = (String) workItem.getParameter("SampleParam");

Example of getting a parameter from the WorkItem class. The name is always a string. For example, WorkItem. In the example, SampleParam is always a string but the object associated with it can be many things and require a cast in order to avoid errors.

// complete workitem impl…

Executes the custom Java code when a parameter is received.

results.put("SampleResult", sampleResult);

Passes results to the custom task. The results are placed in the data output areas of the custom task.

manager.completeWorkItem(workItem.getId(), results);

Marks the work item handler as complete. The WorkItemManager controls the state of the work item and is responsible for getting the WorkItem ID and associate the results with the correct custom task.

abortWorkItem()

Aborts the custom Java code. May be left blank if the work item is not designed to be aborted

Note

Red Hat Process Automation Manager includes a limited set of supported custom tasks. Custom tasks that are not included in Red Hat Process Automation Manager are not supported.