--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/javax/swing/text/LayoutQueue.java Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,121 @@
+/*
+ * Copyright 1999 Sun Microsystems, Inc. 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+package javax.swing.text;
+
+import java.util.Vector;
+
+/**
+ * A queue of text layout tasks.
+ *
+ * @author Timothy Prinzing
+ * @see AsyncBoxView
+ * @since 1.3
+ */
+public class LayoutQueue {
+
+ Vector tasks;
+ Thread worker;
+
+ static LayoutQueue defaultQueue;
+
+ /**
+ * Construct a layout queue.
+ */
+ public LayoutQueue() {
+ tasks = new Vector();
+ }
+
+ /**
+ * Fetch the default layout queue.
+ */
+ public static LayoutQueue getDefaultQueue() {
+ if (defaultQueue == null) {
+ defaultQueue = new LayoutQueue();
+ }
+ return defaultQueue;
+ }
+
+ /**
+ * Set the default layout queue.
+ *
+ * @param q the new queue.
+ */
+ public static void setDefaultQueue(LayoutQueue q) {
+ defaultQueue = q;
+ }
+
+ /**
+ * Add a task that is not needed immediately because
+ * the results are not believed to be visible.
+ */
+ public synchronized void addTask(Runnable task) {
+ if (worker == null) {
+ worker = new LayoutThread();
+ worker.start();
+ }
+ tasks.addElement(task);
+ notifyAll();
+ }
+
+ /**
+ * Used by the worker thread to get a new task to execute
+ */
+ protected synchronized Runnable waitForWork() {
+ while (tasks.size() == 0) {
+ try {
+ wait();
+ } catch (InterruptedException ie) {
+ return null;
+ }
+ }
+ Runnable work = (Runnable) tasks.firstElement();
+ tasks.removeElementAt(0);
+ return work;
+ }
+
+ /**
+ * low priority thread to perform layout work forever
+ */
+ class LayoutThread extends Thread {
+
+ LayoutThread() {
+ super("text-layout");
+ setPriority(Thread.MIN_PRIORITY);
+ }
+
+ public void run() {
+ Runnable work;
+ do {
+ work = waitForWork();
+ if (work != null) {
+ work.run();
+ }
+ } while (work != null);
+ }
+
+
+ }
+
+}