A Workflow is a logical grouping of tasks, done in a set order to accomplish a specific goal. A Workflow is useful when multiple datasets are being processed the same way. The following section describes the key elements of a Workflow implementation.

A walkthrough is available to create a workflow.

ITaskFactory interface

ITASKFACTORY

public class MyTaskFactory implements ITaskFactory {

    public static final String ID = "MyTaskFactory";

    @Override

    public String getId() {

        return ID;

    }

    @Override

    public ITask createTask(String id) {

        return new MyTask(id);

    }

}

ITask interface

ITASK INTERFACE

import com.interactive.intviewerapi.plugins.workflow.AbstractTask;

public class MyTask extends AbstractTask {

    public MyTask(String id) {

        setId(id);

        setName("My Task"); // Name that is displayed in workflow tree

        setStatus(Status.Enabled); // Default value of status, may be set to Status.Disabled

    }

    @Override

    /** The "worker" method for ITask is the runTaskmethod.

     **

     */

    public void runTask() {

        // perform my task action

        doSomething();

    }

}

Register new factory

Register your new task factory in the META-INF.services folder by creating a new file with the name com.interactive.intviewerapi.plugins.workflow.ITaskFactory

In this file add one line for each task factory you have created. In the example, one line would be added:

com.interactive.intviewer.examples.tasks.factories.MyTaskFactory

GUI Integration with INTViewer

The INTViewer uses a workflow configuration file to build and manage a workflow. Create a new WorkflowTasks.xml to describe your workflow.

In the example below the tasklist node denotes groupings within a workflow. For example, a workflow may have several data loading tasks, followed by data processing tasks, followed by data saving tasks. There would be 3 tasklist nodes where the name attribute describes each of the groupings.

TASKLIST NODE

<workflow>

    <tasklist name="Load">

    ...

    </tasklist>

    <tasklist name="Process">

    ...

    </tasklist>

    <tasklist name="Save">

    ...

    </tasklist>

</workflow

In the next example, the task node describes each task within a workflow. There are 4 attributes used to describe each task.

• factory - the factory class written for the task
• tooltip - the text to display in a tool tip. The text displays in the Workflow window when the cursor lingers over this task link.

Changing the status of a task

To change the status of a task, call:

Status status = Status.Enabled // or Status.Disabled

setStatus(status);

You then need to notify any listeners that the status of a task has changed.

To do this, call:

fireListener(this);

The workflow tree, which needs to be notified when the status is changed, is added as a listener when the task is added to the workflow. Calling the fireListener method will notify the workflow tree.

Typically, the status will change due to whether a data type become available or not available. This will

be usually be determined by listening to a lookup event. Here is a simple implementation:

STATUS CHANGE EXAMPLE

   import com.interactive.intviewerapi.GlobalSelection;

import com.interactive.intviewerapi.plugins.workflow.AbstractTask;

import org.openide.util.LookupEvent;

public class MyTask extends AbstractTask implements LookupListener {

    private GlobalSelection<SomeClass> theSelection = new GlobalSelection<SomeClass>(SomeClass.class);

    public MyTask(String id) {

        setId(id);

        setName("My Task"); // Name that is displayed in workflow tree

        setStatus(Status.Enabled); // Default value of status, may be set to Status.Disabled

        theSelection.addLookupListener(this);

    }

    @Override

    public void resultChanged(LookupEvent arg0) {

        Status currentStatus = getStatus();

        Status newStatus;

        Collection<? extends SomeClass> selectionInstances = theSelection.allInstances();

        if (selectionInstances.isEmpty) {

            newStatus = Status.Disabled;

        } else {

            newStatus = Status.Enabled;

        }

        if (newStatus != currentStatus) {

            setStatus(newStatus);

            fireListener(this);

        }

    }

}

The example shows the basic implementation needed by a task to report status back to the Workflow manager.

The tasks that are available, or enabled, are marked with a green icon. Tasks that are not available, or disabled, are marked with a red icon. Use GlobalSelection if you need to keep track of state of the tasks in a workflow.

Two options to open workflow top components are available.