/* * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.swing; import java.util.*; import java.lang.reflect.Array; 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<String> 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> regiouns) 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<Rectangle> args) { * handleDirtyRegions(args); * } * }; * void addDirtyRegion(Rectangle rect) { * doHandleDirtyRegions.add(rect); * } * </pre> * * @author Igor Kushnirskiy * * @param <T> the type this {@code Runnable} accumulates * * @since 1.6 */ public 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 argumets to process. */ protected abstract void run(List<T> args); /** * {@inheritDoc} * * <p> * This implementation calls {@code run(List<T> args)} mehtod * with the list of accumulated arguments. */ public final void run() { run(flush()); } /** * appends arguments and sends this {@cod 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 */ @SafeVarargs @SuppressWarnings("varargs") // Copying args is safe 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; } }