| /* |
| * Copyright (c) 2006, 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.net.httpserver; |
| |
| import java.util.*; |
| import java.nio.*; |
| import java.net.*; |
| import java.io.*; |
| import java.security.*; |
| import java.nio.channels.*; |
| |
| /* |
| * Implements a cache of java.nio.channels.Selector |
| * where Selectors are allocated on demand and placed |
| * in a temporary cache for a period of time, so they |
| * can be reused. If a period of between 2 and 4 minutes |
| * elapses without being used, then they are closed. |
| */ |
| public class SelectorCache { |
| |
| static SelectorCache cache = null; |
| |
| private SelectorCache () { |
| freeSelectors = new LinkedList<SelectorWrapper>(); |
| CacheCleaner c = AccessController.doPrivileged( |
| new PrivilegedAction<CacheCleaner>() { |
| public CacheCleaner run() { |
| CacheCleaner cleaner = new CacheCleaner(); |
| cleaner.setDaemon (true); |
| return cleaner; |
| } |
| }); |
| c.start(); |
| } |
| |
| /** |
| * factory method for creating single instance |
| */ |
| public static SelectorCache getSelectorCache () { |
| synchronized (SelectorCache.class) { |
| if (cache == null) { |
| cache = new SelectorCache (); |
| } |
| } |
| return cache; |
| } |
| |
| private static class SelectorWrapper { |
| private Selector sel; |
| private boolean deleteFlag; |
| private SelectorWrapper (Selector sel) { |
| this.sel = sel; |
| this.deleteFlag = false; |
| } |
| public Selector getSelector() { return sel;} |
| public boolean getDeleteFlag () {return deleteFlag;} |
| public void setDeleteFlag (boolean b) {deleteFlag = b;} |
| } |
| |
| /* list of free selectors. Can be re-allocated for a period |
| * of time, after which if not allocated will be closed |
| * and removed from the list (by CacheCleaner thread) |
| */ |
| LinkedList<SelectorWrapper> freeSelectors; |
| |
| synchronized Selector getSelector () throws IOException { |
| SelectorWrapper wrapper = null; |
| Selector selector; |
| |
| if (freeSelectors.size() > 0) { |
| wrapper = freeSelectors.remove(); |
| selector = wrapper.getSelector(); |
| } else { |
| selector = Selector.open(); |
| } |
| return selector; |
| } |
| |
| synchronized void freeSelector (Selector selector) { |
| freeSelectors.add (new SelectorWrapper (selector)); |
| } |
| |
| /* Thread ensures that entries on freeSelector list |
| * remain there for at least 2 minutes and no longer |
| * than 4 minutes. |
| */ |
| class CacheCleaner extends Thread { |
| public void run () { |
| long timeout = ServerConfig.getSelCacheTimeout() * 1000; |
| while (true) { |
| try {Thread.sleep (timeout); } catch (Exception e) {} |
| synchronized (freeSelectors) { |
| ListIterator<SelectorWrapper> l = freeSelectors.listIterator(); |
| while (l.hasNext()) { |
| SelectorWrapper w = l.next(); |
| if (w.getDeleteFlag()) { |
| /* 2nd pass. Close the selector */ |
| try { |
| w.getSelector().close(); |
| } catch (IOException e) {} |
| l.remove(); |
| } else { |
| /* 1st pass. Set the flag */ |
| w.setDeleteFlag (true); |
| } |
| } |
| } |
| } |
| } |
| } |
| } |