wireload / SwtCallback

SwtCallBack a Java library for SWT that enables callbacks for event handling. SwtCallback is inspired by the Swing enhancer Buoy by Peter Eastman.

SwtCallback

Brevity is the essence of readability and leads to code which sets clear expectations for what should happen. SwtCallback was written to make SWT code, or anything using Runnables, more readable by eliminating repetitive anonymous classes. For instance instead of:

void initWidgets() {
    /* ... */

    // Prime the timer.
    display.timerExec(INITIAL_DELAY, new Runnable() {
        public void run() {
            refresh();
        }
    });
}

void refresh() {
    /* ... update stuff ... */

    // Set the timer again.
    display.timerExec(TIMER_DELAY, new Runnable() {
        public void run() {
            refresh();
        }
    });
}

You can do:

void initWidgets() {
    /* ... */

    // Prime the timer.
    display.timerExec(INITIAL_DELAY, new Callback(this, "refresh"));
}

void refresh() {
    /* ... update stuff ... */

    // Set the timer again.
    display.timerExec(TIMER_DELAY, new Callback(this, "refresh"));
}

For usage with SWT, callbacks transform this:

Button eventButton = new Button(myShell, SWT.NONE);
eventButton.addSelectionListener(new Listener() {
    public void handleEvent(Event event) {
        // Do something
    }
});

Into this:

Button eventButton = new Button(myShell, SWT.NONE);
eventButton.addSelectionListener(new Callback(this, "doEventButtonClicked"));

Building

You need to have an appropriate SWT.jar file in a folder named lib/. Then use the included ant script to compile the jar file.

ant jar

Usage

Put SwtCallback.jar in the class path of your program. See Demo.java for a complete example.

License

Free to use and modify under the terms of the BSD open source license.