/*

 * $Id: AccumulativeRunnable.java,v 1.2 2006/09/28 20:20:28 idk Exp $

 *

 * Copyright Š 2005 Sun Microsystems, Inc. All rights

 * reserved. Use is subject to license terms.

 */



//package org.jdesktop.swingworker;

package ise.plugin.svn.library.swingworker;



import java.util.*;

import javax.swing.SwingUtilities;



/**

 * An abstract class to be used in the cases where we need {@code Runnable}

 * to perform  some actions on an appendable set of data.

 * The set of data might be appended after the {@code Runnable} is

 * sent for the execution. Usually such {@code Runnables} are sent to

 * the EDT.

 *

 * <p>

 * Usage example:

 *

 * <p>

 * Say we want to implement JLabel.setText(String text) which sends

 * {@code text} string to the JLabel.setTextImpl(String text) on the EDT.

 * In the event JLabel.setText is called rapidly many times off the EDT

 * we will get many updates on the EDT but only the last one is important.

 * (Every next updates overrides the previous one.)

 * We might want to implement this {@code setText} in a way that only

 * the last update is delivered.

 * <p>

 * Here is how one can do this using {@code AccumulativeRunnable}:

 * <pre>

 * AccumulativeRunnable<String> doSetTextImpl =

 * new  AccumulativeRunnable<String>() {

 *     @Override

 *     protected void run(List&lt;String&gt; args) {

 *         //set to the last string being passed

 *         setTextImpl(args.get(args.size() - 1);

 *     }

 * }

 * void setText(String text) {

 *     //add text and send for the execution if needed.

 *     doSetTextImpl.add(text);

 * }

 * </pre>

 *

 * <p>

 * Say we want want to implement addDirtyRegion(Rectangle rect)

 * which sends this region to the

 * handleDirtyRegions(List<Rect> regions) on the EDT.

 * addDirtyRegions better be accumulated before handling on the EDT.

 *

 * <p>

 * Here is how it can be implemented using AccumulativeRunnable:

 * <pre>

 * AccumulativeRunnable<Rectangle> doHandleDirtyRegions =

 *     new AccumulativeRunnable<Rectangle>() {

 *         @Override

 *         protected void run(List&lt;Rectangle&gt; args) {

 *             handleDirtyRegions(args);

 *         }

 *     };

 *  void addDirtyRegion(Rectangle rect) {

 *      doHandleDirtyRegions.add(rect);

 *  }

 * </pre>

 *

 * @author Igor Kushnirskiy

 * @version $Revision: 1.2 $ $Date: 2006/09/28 20:20:28 $

 *

 * @param <T> the type this {@code Runnable} accumulates

 *

 */

abstract class AccumulativeRunnable<T> implements Runnable {

    private List<T> arguments = null;



    /**

     * Equivalent to {@code Runnable.run} method with the

     * accumulated arguments to process.

     *

     * @param args accumulated arguments to process.

     */

    protected abstract void run(List<T> args);



    /**

     * {@inheritDoc}

     *

     * <p>

     * This implementation calls {@code run(List<T> args)} method

     * with the list of accumulated arguments.

     */

    public final void run() {

        run(flush());

    }



    /**

     * appends arguments and sends this {@code Runnable} for the

     * execution if needed.

     * <p>

     * This implementation uses {@see #submit} to send this

     * {@code Runnable} for execution.

     * @param args the arguments to accumulate

     */

    public final synchronized void add(T... args) {

        boolean isSubmitted = true;

        if (arguments == null) {

            isSubmitted = false;

            arguments = new ArrayList<T>();

        }

        Collections.addAll(arguments, args);

        if (!isSubmitted) {

            submit();

        }

    }



    /**

     * Sends this {@code Runnable} for the execution

     *

     * <p>

     * This method is to be executed only from {@code add} method.

     *

     * <p>

     * This implementation uses {@code SwingWorker.invokeLater}.

     */

    protected void submit() {

        SwingUtilities.invokeLater(this);

    }



    /**

     * Returns accumulated arguments and flashes the arguments storage.

     *

     * @return accumulated arguments

     */

    private final synchronized List<T> flush() {

        List<T> list = arguments;

        arguments = null;

        return list;

    }

}