001 /* SocketHandler.java -- a class for publishing log messages to network sockets
002 Copyright (C) 2002 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package java.util.logging;
040
041
042 /**
043 * A <code>SocketHandler</code> publishes log records to
044 * a TCP/IP socket.
045 *
046 * <p><strong>Configuration:</strong> Values of the subsequent
047 * <code>LogManager</code> properties are taken into consideration
048 * when a <code>SocketHandler</code> is initialized.
049 * If a property is not defined, or if it has an invalid
050 * value, a default is taken without an exception being thrown.
051 *
052 * <ul>
053 *
054 * <li><code>java.util.SocketHandler.level</code> - specifies
055 * the initial severity level threshold. Default value:
056 * <code>Level.ALL</code>.</li>
057 *
058 * <li><code>java.util.SocketHandler.filter</code> - specifies
059 * the name of a Filter class. Default value: No Filter.</li>
060 *
061 * <li><code>java.util.SocketHandler.formatter</code> - specifies
062 * the name of a Formatter class. Default value:
063 * <code>java.util.logging.XMLFormatter</code>.</li>
064 *
065 * <li><code>java.util.SocketHandler.encoding</code> - specifies
066 * the name of the character encoding. Default value:
067 * the default platform encoding.</li>
068 *
069 * <li><code>java.util.SocketHandler.host</code> - specifies
070 * the name of the host to which records are published.
071 * There is no default value for this property; if it is
072 * not set, the SocketHandler constructor will throw
073 * an exception.</li>
074 *
075 * <li><code>java.util.SocketHandler.port</code> - specifies
076 * the TCP/IP port to which records are published.
077 * There is no default value for this property; if it is
078 * not set, the SocketHandler constructor will throw
079 * an exception.</li>
080 *
081 * </ul>
082 *
083 * @author Sascha Brawer (brawer@acm.org)
084 */
085 public class SocketHandler
086 extends StreamHandler
087 {
088 /**
089 * Constructs a <code>SocketHandler</code> that publishes log
090 * records to a TCP/IP socket. Tthe initial configuration is
091 * determined by the <code>LogManager</code> properties described
092 * above.
093 *
094 * @throws java.io.IOException if the connection to the specified
095 * network host and port cannot be established.
096 *
097 * @throws java.lang.IllegalArgumentException if either the
098 * <code>java.util.logging.SocketHandler.host</code>
099 * or <code>java.util.logging.SocketHandler.port</code>
100 * LogManager properties is not defined, or specifies
101 * an invalid value.
102 */
103 public SocketHandler()
104 throws java.io.IOException
105 {
106 this(LogManager.getLogManager().getProperty("java.util.logging.SocketHandler.host"),
107 getPortNumber());
108 }
109
110
111 /**
112 * Constructs a <code>SocketHandler</code> that publishes log
113 * records to a TCP/IP socket. With the exception of the internet
114 * host and port, the initial configuration is determined by the
115 * <code>LogManager</code> properties described above.
116 *
117 * @param host the Internet host to which log records will be
118 * forwarded.
119 *
120 * @param port the port at the host which will accept a request
121 * for a TCP/IP connection.
122 *
123 * @throws java.io.IOException if the connection to the specified
124 * network host and port cannot be established.
125 *
126 * @throws java.lang.IllegalArgumentException if either
127 * <code>host</code> or <code>port</code> specify
128 * an invalid value.
129 */
130 public SocketHandler(String host, int port)
131 throws java.io.IOException
132 {
133 super(createSocket(host, port),
134 "java.util.logging.SocketHandler",
135 /* default level */ Level.ALL,
136 /* formatter */ null,
137 /* default formatter */ XMLFormatter.class);
138 }
139
140
141 /**
142 * Retrieves the port number from the java.util.logging.SocketHandler.port
143 * LogManager property.
144 *
145 * @throws IllegalArgumentException if the property is not defined or
146 * does not specify an integer value.
147 */
148 private static int getPortNumber()
149 {
150 try {
151 return Integer.parseInt(LogManager.getLogManager().getProperty("java.util.logging.SocketHandler.port"));
152 } catch (Exception ex) {
153 throw new IllegalArgumentException();
154 }
155 }
156
157
158 /**
159 * Creates an OutputStream for publishing log records to an Internet
160 * host and port. This private method is a helper for use by the
161 * constructor of SocketHandler.
162 *
163 * @param host the Internet host to which log records will be
164 * forwarded.
165 *
166 * @param port the port at the host which will accept a request
167 * for a TCP/IP connection.
168 *
169 * @throws java.io.IOException if the connection to the specified
170 * network host and port cannot be established.
171 *
172 * @throws java.lang.IllegalArgumentException if either
173 * <code>host</code> or <code>port</code> specify
174 * an invalid value.
175 */
176 private static java.io.OutputStream createSocket(String host, int port)
177 throws java.io.IOException, java.lang.IllegalArgumentException
178 {
179 java.net.Socket socket;
180
181 if ((host == null) || (port < 1))
182 throw new IllegalArgumentException();
183
184 socket = new java.net.Socket(host, port);
185
186 socket.shutdownInput();
187
188 /* The architecture of the logging framework provides replaceable
189 * formatters. Because these formatters perform their task by
190 * returning one single String for each LogRecord to be formatted,
191 * there is no need to buffer.
192 */
193 socket.setTcpNoDelay(true);
194
195 return socket.getOutputStream();
196 }
197
198
199 /**
200 * Publishes a <code>LogRecord</code> to the network socket,
201 * provided the record passes all tests for being loggable.
202 * In addition, all data that may have been buffered will
203 * be forced to the network stream.
204 *
205 * <p>Most applications do not need to call this method directly.
206 * Instead, they will use a {@link Logger} instance, which will
207 * create LogRecords and distribute them to registered handlers.
208 *
209 * <p>In case of an I/O failure, the <code>ErrorManager</code>
210 * of this <code>SocketHandler</code> will be informed, but the caller
211 * of this method will not receive an exception.
212 *
213 * @param record the log event to be published.
214 */
215 public void publish(LogRecord record)
216 {
217 super.publish(record);
218 flush();
219 }
220 }