1 /* 2 * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.nio.ch; 27 28 import java.nio.channels.spi.AsynchronousChannelProvider; 29 import java.nio.channels.*; 30 import java.io.IOException; 31 import java.io.Closeable; 32 import java.io.FileDescriptor; 33 import java.util.Map; 34 import java.util.HashMap; 35 import java.util.concurrent.locks.ReadWriteLock; 36 import java.util.concurrent.locks.ReentrantReadWriteLock; 37 38 /** 39 * Base implementation of AsynchronousChannelGroupImpl for Unix systems. 40 */ 41 42 abstract class Port extends AsynchronousChannelGroupImpl { 43 44 /** 45 * Implemented by clients registered with this port. 46 */ 47 interface PollableChannel extends Closeable { onEvent(int events, boolean mayInvokeDirect)48 void onEvent(int events, boolean mayInvokeDirect); 49 } 50 51 // maps fd to "pollable" channel 52 protected final ReadWriteLock fdToChannelLock = new ReentrantReadWriteLock(); 53 protected final Map<Integer,PollableChannel> fdToChannel = 54 new HashMap<Integer,PollableChannel>(); 55 56 Port(AsynchronousChannelProvider provider, ThreadPool pool)57 Port(AsynchronousChannelProvider provider, ThreadPool pool) { 58 super(provider, pool); 59 } 60 61 /** 62 * Register channel identified by its file descriptor 63 */ register(int fd, PollableChannel ch)64 final void register(int fd, PollableChannel ch) { 65 fdToChannelLock.writeLock().lock(); 66 try { 67 if (isShutdown()) 68 throw new ShutdownChannelGroupException(); 69 fdToChannel.put(Integer.valueOf(fd), ch); 70 } finally { 71 fdToChannelLock.writeLock().unlock(); 72 } 73 } 74 75 /** 76 * Callback method for implementations that need special handling when fd is 77 * removed (currently only needed in the AIX-Port - see AixPollPort.java). 78 */ preUnregister(int fd)79 protected void preUnregister(int fd) { 80 // Do nothing by default. 81 } 82 83 /** 84 * Unregister channel identified by its file descriptor 85 */ unregister(int fd)86 final void unregister(int fd) { 87 boolean checkForShutdown = false; 88 89 preUnregister(fd); 90 91 fdToChannelLock.writeLock().lock(); 92 try { 93 fdToChannel.remove(Integer.valueOf(fd)); 94 95 // last key to be removed so check if group is shutdown 96 if (fdToChannel.isEmpty()) 97 checkForShutdown = true; 98 99 } finally { 100 fdToChannelLock.writeLock().unlock(); 101 } 102 103 // continue shutdown 104 if (checkForShutdown && isShutdown()) { 105 try { 106 shutdownNow(); 107 } catch (IOException ignore) { } 108 } 109 } 110 /** 111 * Register file descriptor with polling mechanism for given events. 112 * The implementation should translate the events as required. 113 */ startPoll(int fd, int events)114 abstract void startPoll(int fd, int events); 115 116 @Override isEmpty()117 final boolean isEmpty() { 118 fdToChannelLock.writeLock().lock(); 119 try { 120 return fdToChannel.isEmpty(); 121 } finally { 122 fdToChannelLock.writeLock().unlock(); 123 } 124 } 125 126 @Override attachForeignChannel(final Channel channel, FileDescriptor fd)127 final Object attachForeignChannel(final Channel channel, FileDescriptor fd) { 128 int fdVal = IOUtil.fdVal(fd); 129 register(fdVal, new PollableChannel() { 130 public void onEvent(int events, boolean mayInvokeDirect) { } 131 public void close() throws IOException { 132 channel.close(); 133 } 134 }); 135 return Integer.valueOf(fdVal); 136 } 137 138 @Override detachForeignChannel(Object key)139 final void detachForeignChannel(Object key) { 140 unregister((Integer)key); 141 } 142 143 @Override closeAllChannels()144 final void closeAllChannels() { 145 /** 146 * Close channels in batches of up to 128 channels. This allows close 147 * to remove the channel from the map without interference. 148 */ 149 final int MAX_BATCH_SIZE = 128; 150 PollableChannel channels[] = new PollableChannel[MAX_BATCH_SIZE]; 151 int count; 152 do { 153 // grab a batch of up to 128 channels 154 fdToChannelLock.writeLock().lock(); 155 count = 0; 156 try { 157 for (Integer fd: fdToChannel.keySet()) { 158 channels[count++] = fdToChannel.get(fd); 159 if (count >= MAX_BATCH_SIZE) 160 break; 161 } 162 } finally { 163 fdToChannelLock.writeLock().unlock(); 164 } 165 166 // close them 167 for (int i=0; i<count; i++) { 168 try { 169 channels[i].close(); 170 } catch (IOException ignore) { } 171 } 172 } while (count > 0); 173 } 174 } 175