JavaFX using JDK1.8 Lambda Expression

This is 21th of the JavaFX Advent Calendar (see JavaFX Advent Calendar 2012 : ATND for other articles)
This is my first article in English so if you find any mistakes feel free to give me comments.
I use Mac OS X 10.7.4 and JDK1.8.0

The following shows the screen I write with lambda expression and javafx concurrent task.

• Start

• Progressing

Click the Start button to start the task.The Progress Bar fills as the operation progresses and the text message continually updates to indicate the percentage of progress completed.

• Done and Cancelled

Click the Cancel button to cancel the task.

Below is the lambda expression I write in this example.

• for Task1

It is possible to use lambda expression to set action or add event handler

        EventHandler<ActionEvent> sHandler = e -> {
            btn1.setDisable(true);
            btnC1.setDisable(false);
            task1 = new ProgressTask("Task1", 10);
            bar1.progressProperty().bind(task1.progressProperty());
            text1.textProperty().bind(task1.messageProperty());
            service.submit(task1);
            EventHandler<WorkerStateEvent> tHandler = 
                ee -> {btn1.setDisable(false);
                      btnC1.setDisable(true);};
            task1.addEventHandler(
                WorkerStateEvent.WORKER_STATE_SUCCEEDED, tHandler); 
            task1.addEventHandler(
                WorkerStateEvent.WORKER_STATE_CANCELLED, tHandler); 
            };
        btn1.setOnAction(sHandler);
        EventHandler<ActionEvent> cHandler = 
            e -> {task1.cancel();};
        btnC1.setOnAction(cHandler);

• for Task2

Implementation almost same as task 1, but use lambda expression in parameter

       btn2.setOnAction(e -> {
            btn2.setDisable(true);
            btnC2.setDisable(false);
            task2 = new ProgressTask("Task2", 20);
            bar2.progressProperty().bind(task2.progressProperty());
            text2.textProperty().bind(task2.messageProperty());
            service.submit(task2);
            task2.addEventHandler(
                WorkerStateEvent.WORKER_STATE_SUCCEEDED, 
                ee -> {btn2.setDisable(false);
                      btnC2.setDisable(true);}
            );
            task2.addEventHandler(
                WorkerStateEvent.WORKER_STATE_CANCELLED, 
                ee -> {btn2.setDisable(false);
                      btnC2.setDisable(true);}
            );
        });
        btnC2.setOnAction(e -> {task2.cancel();});

• for Task

There is no lambda expression.
I want to update message when the task cancelled then extend the Task and Override cancelled method.

public class ProgressTask extends Task<String> {
    private String taskName;
    private int numberOfTask;

    public ProgressTask(String taskName, int numberOfTask) {
        this.taskName = taskName;
        this.numberOfTask = numberOfTask;
    }

    @Override
    protected String call() throws Exception {
        updateMessage("started");
        int i;
        for (i = 1; i <= numberOfTask; i++) {
            if (isCancelled()) {
                updateMessage("??? cancelled ???");  // this dose not work???
                break;
            }
            updateProgress(i, numberOfTask);
            TimeUnit.SECONDS.sleep(1);
            updateMessage(String.format("running %d/%d", i, numberOfTask));
        }
        updateMessage("done");
        return "Done";
    }

    @Override
    protected void updateMessage(String string) {
        super.updateMessage(taskName + " " + string);
    }

    @Override
    protected void cancelled() {
        updateProgress(0, numberOfTask);
        updateMessage("cancelled");
        super.cancelled();
    }
    
}

I hope this helps you write JavaFX with lambda expressions as well as javafx concurrent task.
I put all sources to github.(see tomoTaka01/progresssample: JavaFX using JDK... - GitHub)
Have a nice holiday!