001/* SocketHandler.java -- a class for publishing log messages to network sockets
002   Copyright (C) 2002 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package 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 */
085public 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}
221