author | bae |
Fri, 16 Nov 2012 11:05:43 +0400 | |
changeset 16093 | b305a8dc867f |
parent 9035 | 1255eb81cc2f |
child 22567 | 5816a47fa4dd |
permissions | -rw-r--r-- |
2 | 1 |
/* |
9035
1255eb81cc2f
7033660: Update copyright year to 2011 on any files changed in 2011
ohair
parents:
8353
diff
changeset
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* Copyright (c) 1995, 2011, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package sun.awt.image; |
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import java.util.Vector; |
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import sun.awt.AppContext; |
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/** |
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* An ImageFetcher is a thread used to fetch ImageFetchable objects. |
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* Once an ImageFetchable object has been fetched, the ImageFetcher |
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* thread may also be used to animate it if necessary, via the |
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* startingAnimation() / stoppingAnimation() methods. |
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* |
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* There can be up to FetcherInfo.MAX_NUM_FETCHERS_PER_APPCONTEXT |
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* ImageFetcher threads for each AppContext. A per-AppContext queue |
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* of ImageFetchables is used to track objects to fetch. |
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* |
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* @author Jim Graham |
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* @author Fred Ecks |
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*/ |
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class ImageFetcher extends Thread { |
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static final int HIGH_PRIORITY = 8; |
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static final int LOW_PRIORITY = 3; |
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static final int ANIM_PRIORITY = 2; |
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static final int TIMEOUT = 5000; // Time in milliseconds to wait for an |
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// ImageFetchable to be added to the |
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// queue before an ImageFetcher dies |
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/** |
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* Constructor for ImageFetcher -- only called by add() below. |
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*/ |
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private ImageFetcher(ThreadGroup threadGroup, int index) { |
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super(threadGroup, "Image Fetcher " + index); |
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setDaemon(true); |
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} |
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/** |
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* Adds an ImageFetchable to the queue of items to fetch. Instantiates |
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* a new ImageFetcher if it's reasonable to do so. |
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* If there is no available fetcher to process an ImageFetchable, then |
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* reports failure to caller. |
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*/ |
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public static boolean add(ImageFetchable src) { |
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final FetcherInfo info = FetcherInfo.getFetcherInfo(); |
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synchronized(info.waitList) { |
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if (!info.waitList.contains(src)) { |
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info.waitList.addElement(src); |
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if (info.numWaiting == 0 && |
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info.numFetchers < info.fetchers.length) { |
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createFetchers(info); |
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} |
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/* Creation of new fetcher may fail due to high vm load |
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* or some other reason. |
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* If there is already exist, but busy, fetcher, we leave |
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* the src in queue (it will be handled by existing |
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* fetcher later). |
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* Otherwise, we report failure: there is no fetcher |
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* to handle the src. |
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*/ |
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if (info.numFetchers > 0) { |
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info.waitList.notify(); |
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} else { |
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info.waitList.removeElement(src); |
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return false; |
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} |
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} |
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} |
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return true; |
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} |
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/** |
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* Removes an ImageFetchable from the queue of items to fetch. |
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*/ |
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public static void remove(ImageFetchable src) { |
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final FetcherInfo info = FetcherInfo.getFetcherInfo(); |
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synchronized(info.waitList) { |
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if (info.waitList.contains(src)) { |
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info.waitList.removeElement(src); |
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} |
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} |
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} |
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/** |
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* Checks to see if the given thread is one of the ImageFetchers. |
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*/ |
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public static boolean isFetcher(Thread t) { |
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final FetcherInfo info = FetcherInfo.getFetcherInfo(); |
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synchronized(info.waitList) { |
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for (int i = 0; i < info.fetchers.length; i++) { |
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if (info.fetchers[i] == t) { |
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return true; |
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} |
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} |
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} |
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return false; |
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} |
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/** |
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* Checks to see if the current thread is one of the ImageFetchers. |
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*/ |
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public static boolean amFetcher() { |
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return isFetcher(Thread.currentThread()); |
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} |
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/** |
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* Returns the next ImageFetchable to be processed. If TIMEOUT |
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* elapses in the mean time, or if the ImageFetcher is interrupted, |
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* null is returned. |
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*/ |
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private static ImageFetchable nextImage() { |
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final FetcherInfo info = FetcherInfo.getFetcherInfo(); |
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synchronized(info.waitList) { |
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ImageFetchable src = null; |
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long end = System.currentTimeMillis() + TIMEOUT; |
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while (src == null) { |
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while (info.waitList.size() == 0) { |
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long now = System.currentTimeMillis(); |
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if (now >= end) { |
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return null; |
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} |
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try { |
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info.numWaiting++; |
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info.waitList.wait(end - now); |
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} catch (InterruptedException e) { |
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// A normal occurrence as an AppContext is disposed |
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return null; |
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} finally { |
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info.numWaiting--; |
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} |
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} |
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src = (ImageFetchable) info.waitList.elementAt(0); |
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info.waitList.removeElement(src); |
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} |
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return src; |
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} |
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} |
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/** |
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* The main run() method of an ImageFetcher Thread. Calls fetchloop() |
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* to do the work, then removes itself from the array of ImageFetchers. |
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*/ |
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public void run() { |
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final FetcherInfo info = FetcherInfo.getFetcherInfo(); |
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try { |
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fetchloop(); |
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} catch (Exception e) { |
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e.printStackTrace(); |
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} finally { |
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synchronized(info.waitList) { |
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Thread me = Thread.currentThread(); |
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for (int i = 0; i < info.fetchers.length; i++) { |
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if (info.fetchers[i] == me) { |
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info.fetchers[i] = null; |
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info.numFetchers--; |
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} |
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} |
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} |
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} |
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} |
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/** |
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* The main ImageFetcher loop. Repeatedly calls nextImage(), and |
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* fetches the returned ImageFetchable objects until nextImage() |
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* returns null. |
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*/ |
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private void fetchloop() { |
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Thread me = Thread.currentThread(); |
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while (isFetcher(me)) { |
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// we're ignoring the return value and just clearing |
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// the interrupted flag, instead of bailing out if |
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// the fetcher was interrupted, as we used to, |
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// because there may be other images waiting |
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// to be fetched (see 4789067) |
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me.interrupted(); |
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me.setPriority(HIGH_PRIORITY); |
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ImageFetchable src = nextImage(); |
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if (src == null) { |
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return; |
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} |
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try { |
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src.doFetch(); |
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} catch (Exception e) { |
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System.err.println("Uncaught error fetching image:"); |
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e.printStackTrace(); |
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} |
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stoppingAnimation(me); |
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} |
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} |
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/** |
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* Recycles this ImageFetcher thread as an image animator thread. |
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* Removes this ImageFetcher from the array of ImageFetchers, and |
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* resets the thread name to "ImageAnimator". |
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*/ |
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static void startingAnimation() { |
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final FetcherInfo info = FetcherInfo.getFetcherInfo(); |
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Thread me = Thread.currentThread(); |
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synchronized(info.waitList) { |
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for (int i = 0; i < info.fetchers.length; i++) { |
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if (info.fetchers[i] == me) { |
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info.fetchers[i] = null; |
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info.numFetchers--; |
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me.setName("Image Animator " + i); |
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if(info.waitList.size() > info.numWaiting) { |
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createFetchers(info); |
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} |
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return; |
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} |
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} |
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} |
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me.setPriority(ANIM_PRIORITY); |
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me.setName("Image Animator"); |
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} |
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/** |
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* Returns this image animator thread back to service as an ImageFetcher |
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* if possible. Puts it back into the array of ImageFetchers and sets |
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* the thread name back to "Image Fetcher". If there are already the |
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* maximum number of ImageFetchers, this method simply returns, and |
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* fetchloop() will drop out when it sees that this thread isn't one of |
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* the ImageFetchers, and this thread will die. |
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*/ |
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private static void stoppingAnimation(Thread me) { |
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final FetcherInfo info = FetcherInfo.getFetcherInfo(); |
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synchronized(info.waitList) { |
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int index = -1; |
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for (int i = 0; i < info.fetchers.length; i++) { |
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if (info.fetchers[i] == me) { |
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return; |
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} |
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if (info.fetchers[i] == null) { |
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index = i; |
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} |
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} |
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if (index >= 0) { |
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info.fetchers[index] = me; |
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info.numFetchers++; |
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me.setName("Image Fetcher " + index); |
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return; |
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} |
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} |
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} |
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/** |
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* Create and start ImageFetcher threads in the appropriate ThreadGroup. |
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*/ |
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private static void createFetchers(final FetcherInfo info) { |
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// We need to instantiate a new ImageFetcher thread. |
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// First, figure out which ThreadGroup we'll put the |
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// new ImageFetcher into |
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final AppContext appContext = AppContext.getAppContext(); |
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ThreadGroup threadGroup = appContext.getThreadGroup(); |
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ThreadGroup fetcherThreadGroup; |
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try { |
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280 |
if (threadGroup.getParent() != null) { |
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// threadGroup is not the root, so we proceed |
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fetcherThreadGroup = threadGroup; |
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} else { |
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// threadGroup is the root ("system") ThreadGroup. |
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// We instead want to use its child: the "main" |
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// ThreadGroup. Thus, we start with the current |
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// ThreadGroup, and go up the tree until |
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// threadGroup.getParent().getParent() == null. |
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threadGroup = Thread.currentThread().getThreadGroup(); |
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ThreadGroup parent = threadGroup.getParent(); |
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while ((parent != null) |
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&& (parent.getParent() != null)) { |
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threadGroup = parent; |
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parent = threadGroup.getParent(); |
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} |
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fetcherThreadGroup = threadGroup; |
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} |
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} catch (SecurityException e) { |
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// Not allowed access to parent ThreadGroup -- just use |
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// the AppContext's ThreadGroup |
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fetcherThreadGroup = appContext.getThreadGroup(); |
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} |
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final ThreadGroup fetcherGroup = fetcherThreadGroup; |
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305 |
java.security.AccessController.doPrivileged( |
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306 |
new java.security.PrivilegedAction() { |
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307 |
public Object run() { |
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308 |
for (int i = 0; i < info.fetchers.length; i++) { |
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309 |
if (info.fetchers[i] == null) { |
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8353 | 310 |
ImageFetcher f = new ImageFetcher( |
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fetcherGroup, i); |
8353 | 312 |
try { |
313 |
f.start(); |
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314 |
info.fetchers[i] = f; |
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315 |
info.numFetchers++; |
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break; |
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} catch (Error e) { |
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318 |
} |
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} |
320 |
} |
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321 |
return null; |
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322 |
} |
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}); |
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324 |
return; |
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325 |
} |
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326 |
||
327 |
} |
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328 |
||
329 |
/** |
|
330 |
* The FetcherInfo class encapsulates the per-AppContext ImageFetcher |
|
331 |
* information. This includes the array of ImageFetchers, as well as |
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332 |
* the queue of ImageFetchable objects. |
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333 |
*/ |
|
334 |
class FetcherInfo { |
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335 |
static final int MAX_NUM_FETCHERS_PER_APPCONTEXT = 4; |
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336 |
||
337 |
Thread[] fetchers; |
|
338 |
int numFetchers; |
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339 |
int numWaiting; |
|
340 |
Vector waitList; |
|
341 |
||
342 |
private FetcherInfo() { |
|
343 |
fetchers = new Thread[MAX_NUM_FETCHERS_PER_APPCONTEXT]; |
|
344 |
numFetchers = 0; |
|
345 |
numWaiting = 0; |
|
346 |
waitList = new Vector(); |
|
347 |
} |
|
348 |
||
349 |
/* The key to put()/get() the FetcherInfo into/from the AppContext. */ |
|
350 |
private static final Object FETCHER_INFO_KEY = |
|
351 |
new StringBuffer("FetcherInfo"); |
|
352 |
||
353 |
static FetcherInfo getFetcherInfo() { |
|
354 |
AppContext appContext = AppContext.getAppContext(); |
|
355 |
synchronized(appContext) { |
|
356 |
FetcherInfo info = (FetcherInfo)appContext.get(FETCHER_INFO_KEY); |
|
357 |
if (info == null) { |
|
358 |
info = new FetcherInfo(); |
|
359 |
appContext.put(FETCHER_INFO_KEY, info); |
|
360 |
} |
|
361 |
return info; |
|
362 |
} |
|
363 |
} |
|
364 |
} |