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 static final short POLLIN = 0x0001;
44 static final short POLLOUT = 0x0004;
45 static final short POLLERR = 0x0008;
46 static final short POLLHUP = 0x0010;
47
48 /**
49 * Implemented by clients registered with this port.
50 */
51 interface PollableChannel extends Closeable {
52 void onEvent(int events, boolean mayInvokeDirect);
53 }
54
55 // maps fd to "pollable" channel
56 protected final ReadWriteLock fdToChannelLock = new ReentrantReadWriteLock();
57 protected final Map<Integer,PollableChannel> fdToChannel =
58 new HashMap<Integer,PollableChannel>();
59
60
61 Port(AsynchronousChannelProvider provider, ThreadPool pool) {
62 super(provider, pool);
63 }
64
65 /**
66 * Register channel identified by its file descriptor
67 */
68 final void register(int fd, PollableChannel ch) {
69 fdToChannelLock.writeLock().lock();
70 try {
71 if (isShutdown())
72 throw new ShutdownChannelGroupException();
73 fdToChannel.put(Integer.valueOf(fd), ch);
74 } finally {
75 fdToChannelLock.writeLock().unlock();
76 }
77 }
78
79 /**
80 * Callback method for implementations that need special handling when fd is
81 * removed (currently only needed in the AIX-Port - see AixPollPort.java).
82 */
83 protected void preUnregister(int fd) {
84 // Do nothing by default.
85 }
86
87 /**
88 * Unregister channel identified by its file descriptor
89 */
90 final void unregister(int fd) {
91 boolean checkForShutdown = false;
92
93 preUnregister(fd);
94
95 fdToChannelLock.writeLock().lock();
96 try {
97 fdToChannel.remove(Integer.valueOf(fd));
98
99 // last key to be removed so check if group is shutdown
100 if (fdToChannel.isEmpty())
101 checkForShutdown = true;
102
103 } finally {
104 fdToChannelLock.writeLock().unlock();
105 }
106
107 // continue shutdown
108 if (checkForShutdown && isShutdown()) {
109 try {
110 shutdownNow();
111 } catch (IOException ignore) { }
112 }
113 }
114 /**
115 * Register file descriptor with polling mechanism for given events.
116 * The implementation should translate the events as required.
117 */
118 abstract void startPoll(int fd, int events);
119
120 @Override
121 final boolean isEmpty() {
122 fdToChannelLock.writeLock().lock();
123 try {
124 return fdToChannel.isEmpty();
125 } finally {
126 fdToChannelLock.writeLock().unlock();
127 }
128 }
129
130 @Override
131 final Object attachForeignChannel(final Channel channel, FileDescriptor fd) {
132 int fdVal = IOUtil.fdVal(fd);
133 register(fdVal, new PollableChannel() {
134 public void onEvent(int events, boolean mayInvokeDirect) { }
135 public void close() throws IOException {
136 channel.close();
137 }
138 });
139 return Integer.valueOf(fdVal);
140 }
141
142 @Override
143 final void detachForeignChannel(Object key) {
144 unregister((Integer)key);
145 }
146
147 @Override
148 final void closeAllChannels() {
149 /**
150 * Close channels in batches of up to 128 channels. This allows close
151 * to remove the channel from the map without interference.
152 */
153 final int MAX_BATCH_SIZE = 128;
154 PollableChannel channels[] = new PollableChannel[MAX_BATCH_SIZE];
155 int count;
156 do {
157 // grab a batch of up to 128 channels
158 fdToChannelLock.writeLock().lock();
159 count = 0;
160 try {
161 for (Integer fd: fdToChannel.keySet()) {
162 channels[count++] = fdToChannel.get(fd);
163 if (count >= MAX_BATCH_SIZE)
164 break;
165 }
166 } finally {
167 fdToChannelLock.writeLock().unlock();
168 }
169
170 // close them
171 for (int i=0; i<count; i++) {
172 try {
173 channels[i].close();
174 } catch (IOException ignore) { }
175 }
176 } while (count > 0);
177 }
178 }