swing-tasks

This is a small library that aims to help with executing tasks from swing applications. It consist of a set of classes that build around the SwingWorker class.

Dependencies

The only dependency is to the slf4j logging api.

Compile

Use maven to compile the sources:

mvn install

Usage

The class TaskManager is the main entry point. Usually, you would use this as an application wide singleton. The TaskManager is used to submit tasks that implement either Task, Callable or Runnable. It can query currently active tasks and can be used to register listeners that receive events from running tasks.

TaskManager taskManager = new TaskManagerImpl();

For swing related tasks, it is recommended to implement the Task interface, as it mimics the SwingWorker interface and thus provides some features regarding swing. The TaskManager creates a TaskControl object for each Task that provides the usual control methods and additionally defines a method to get the TaskContext of the current task. The TaskContext can be used to get some information about the task and to add listeners that receive events for this task only.

If a Task is submitted a TaskControl object is received in response. But task has not been started yet and is still in state PENDING. In order to start the task, call execute() on the TaskControl object. The idea is to be able to register listeners for exactly this task prior to starting it. Example:

Task<Long, Long> task = new LongTask();
TaskControl<Long> control = taskManager.create(task);
control.getContext().addListener(new TaskListener() {
  @Override
  public void stateChanged(ChangeEvent<State> event) {
    log.info(">>> State: " + event.getOldValue() + " => " + event.getNewValue());
    log.info("Started: " + event.getSource().getStartedTimestamp());
  }

  @Override
  public void progressChanged(ChangeEvent<Integer> event) {
    log.info(">>> Progress: " + event.getOldValue() + " => " + event.getNewValue());
  }

  @Override
  public void phaseChanged(ChangeEvent<String> event) {
    log.info(">>> Phase: " + event.getOldValue() + " => " + event.getNewValue());
  }
});
Long value = control.waitFor();
log.info("Waited for task: " + value);

The package org.eknet.swing.task.ui provides some simple swing ui classes for displaying running task and a default glass pane. You can use the glass pane with a JFrame. It will popup if any task of mode BLOCKING is executed and shows a list of tasks currently running -- as well as a button to cancel them.

JFrame frame = new JFrame("my app");
frame.setGlassPane(new TaskGlassPane(taskManager));