1 /* 2 * Copyright (c) 2000, 2013, 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 27 package java.util.logging; 28 29 import java.io.*; 30 31 /** 32 * Stream based logging <tt>Handler</tt>. 33 * <p> 34 * This is primarily intended as a base class or support class to 35 * be used in implementing other logging <tt>Handlers</tt>. 36 * <p> 37 * <tt>LogRecords</tt> are published to a given <tt>java.io.OutputStream</tt>. 38 * <p> 39 * <b>Configuration:</b> 40 * By default each <tt>StreamHandler</tt> is initialized using the following 41 * <tt>LogManager</tt> configuration properties where <tt><handler-name></tt> 42 * refers to the fully-qualified class name of the handler. 43 * If properties are not defined 44 * (or have invalid values) then the specified default values are used. 45 * <ul> 46 * <li> <handler-name>.level 47 * specifies the default level for the <tt>Handler</tt> 48 * (defaults to <tt>Level.INFO</tt>). </li> 49 * <li> <handler-name>.filter 50 * specifies the name of a <tt>Filter</tt> class to use 51 * (defaults to no <tt>Filter</tt>). </li> 52 * <li> <handler-name>.formatter 53 * specifies the name of a <tt>Formatter</tt> class to use 54 * (defaults to <tt>java.util.logging.SimpleFormatter</tt>). </li> 55 * <li> <handler-name>.encoding 56 * the name of the character set encoding to use (defaults to 57 * the default platform encoding). </li> 58 * </ul> 59 * <p> 60 * For example, the properties for {@code StreamHandler} would be: 61 * <ul> 62 * <li> java.util.logging.StreamHandler.level=INFO </li> 63 * <li> java.util.logging.StreamHandler.formatter=java.util.logging.SimpleFormatter </li> 64 * </ul> 65 * <p> 66 * For a custom handler, e.g. com.foo.MyHandler, the properties would be: 67 * <ul> 68 * <li> com.foo.MyHandler.level=INFO </li> 69 * <li> com.foo.MyHandler.formatter=java.util.logging.SimpleFormatter </li> 70 * </ul> 71 * <p> 72 * @since 1.4 73 */ 74 75 public class StreamHandler extends Handler { 76 private OutputStream output; 77 private boolean doneHeader; 78 private volatile Writer writer; 79 80 // Private method to configure a StreamHandler from LogManager 81 // properties and/or default values as specified in the class 82 // javadoc. configure()83 private void configure() { 84 LogManager manager = LogManager.getLogManager(); 85 String cname = getClass().getName(); 86 87 setLevel(manager.getLevelProperty(cname +".level", Level.INFO)); 88 setFilter(manager.getFilterProperty(cname +".filter", null)); 89 setFormatter(manager.getFormatterProperty(cname +".formatter", new SimpleFormatter())); 90 try { 91 setEncoding(manager.getStringProperty(cname +".encoding", null)); 92 } catch (Exception ex) { 93 try { 94 setEncoding(null); 95 } catch (Exception ex2) { 96 // doing a setEncoding with null should always work. 97 // assert false; 98 } 99 } 100 } 101 102 /** 103 * Create a <tt>StreamHandler</tt>, with no current output stream. 104 */ StreamHandler()105 public StreamHandler() { 106 sealed = false; 107 configure(); 108 sealed = true; 109 } 110 111 /** 112 * Create a <tt>StreamHandler</tt> with a given <tt>Formatter</tt> 113 * and output stream. 114 * <p> 115 * @param out the target output stream 116 * @param formatter Formatter to be used to format output 117 */ StreamHandler(OutputStream out, Formatter formatter)118 public StreamHandler(OutputStream out, Formatter formatter) { 119 sealed = false; 120 configure(); 121 setFormatter(formatter); 122 setOutputStream(out); 123 sealed = true; 124 } 125 126 /** 127 * Change the output stream. 128 * <P> 129 * If there is a current output stream then the <tt>Formatter</tt>'s 130 * tail string is written and the stream is flushed and closed. 131 * Then the output stream is replaced with the new output stream. 132 * 133 * @param out New output stream. May not be null. 134 * @exception SecurityException if a security manager exists and if 135 * the caller does not have <tt>LoggingPermission("control")</tt>. 136 */ setOutputStream(OutputStream out)137 protected synchronized void setOutputStream(OutputStream out) throws SecurityException { 138 if (out == null) { 139 throw new NullPointerException(); 140 } 141 flushAndClose(); 142 output = out; 143 doneHeader = false; 144 String encoding = getEncoding(); 145 if (encoding == null) { 146 writer = new OutputStreamWriter(output); 147 } else { 148 try { 149 writer = new OutputStreamWriter(output, encoding); 150 } catch (UnsupportedEncodingException ex) { 151 // This shouldn't happen. The setEncoding method 152 // should have validated that the encoding is OK. 153 throw new Error("Unexpected exception " + ex); 154 } 155 } 156 } 157 158 /** 159 * Set (or change) the character encoding used by this <tt>Handler</tt>. 160 * <p> 161 * The encoding should be set before any <tt>LogRecords</tt> are written 162 * to the <tt>Handler</tt>. 163 * 164 * @param encoding The name of a supported character encoding. 165 * May be null, to indicate the default platform encoding. 166 * @exception SecurityException if a security manager exists and if 167 * the caller does not have <tt>LoggingPermission("control")</tt>. 168 * @exception UnsupportedEncodingException if the named encoding is 169 * not supported. 170 */ 171 @Override setEncoding(String encoding)172 public synchronized void setEncoding(String encoding) 173 throws SecurityException, java.io.UnsupportedEncodingException { 174 super.setEncoding(encoding); 175 if (output == null) { 176 return; 177 } 178 // Replace the current writer with a writer for the new encoding. 179 flush(); 180 if (encoding == null) { 181 writer = new OutputStreamWriter(output); 182 } else { 183 writer = new OutputStreamWriter(output, encoding); 184 } 185 } 186 187 /** 188 * Format and publish a <tt>LogRecord</tt>. 189 * <p> 190 * The <tt>StreamHandler</tt> first checks if there is an <tt>OutputStream</tt> 191 * and if the given <tt>LogRecord</tt> has at least the required log level. 192 * If not it silently returns. If so, it calls any associated 193 * <tt>Filter</tt> to check if the record should be published. If so, 194 * it calls its <tt>Formatter</tt> to format the record and then writes 195 * the result to the current output stream. 196 * <p> 197 * If this is the first <tt>LogRecord</tt> to be written to a given 198 * <tt>OutputStream</tt>, the <tt>Formatter</tt>'s "head" string is 199 * written to the stream before the <tt>LogRecord</tt> is written. 200 * 201 * @param record description of the log event. A null record is 202 * silently ignored and is not published 203 */ 204 @Override publish(LogRecord record)205 public synchronized void publish(LogRecord record) { 206 if (!isLoggable(record)) { 207 return; 208 } 209 String msg; 210 try { 211 msg = getFormatter().format(record); 212 } catch (Exception ex) { 213 // We don't want to throw an exception here, but we 214 // report the exception to any registered ErrorManager. 215 reportError(null, ex, ErrorManager.FORMAT_FAILURE); 216 return; 217 } 218 219 try { 220 if (!doneHeader) { 221 writer.write(getFormatter().getHead(this)); 222 doneHeader = true; 223 } 224 writer.write(msg); 225 } catch (Exception ex) { 226 // We don't want to throw an exception here, but we 227 // report the exception to any registered ErrorManager. 228 reportError(null, ex, ErrorManager.WRITE_FAILURE); 229 } 230 } 231 232 233 /** 234 * Check if this <tt>Handler</tt> would actually log a given <tt>LogRecord</tt>. 235 * <p> 236 * This method checks if the <tt>LogRecord</tt> has an appropriate level and 237 * whether it satisfies any <tt>Filter</tt>. It will also return false if 238 * no output stream has been assigned yet or the LogRecord is null. 239 * <p> 240 * @param record a <tt>LogRecord</tt> 241 * @return true if the <tt>LogRecord</tt> would be logged. 242 * 243 */ 244 @Override isLoggable(LogRecord record)245 public boolean isLoggable(LogRecord record) { 246 if (writer == null || record == null) { 247 return false; 248 } 249 return super.isLoggable(record); 250 } 251 252 /** 253 * Flush any buffered messages. 254 */ 255 @Override flush()256 public synchronized void flush() { 257 if (writer != null) { 258 try { 259 writer.flush(); 260 } catch (Exception ex) { 261 // We don't want to throw an exception here, but we 262 // report the exception to any registered ErrorManager. 263 reportError(null, ex, ErrorManager.FLUSH_FAILURE); 264 } 265 } 266 } 267 flushAndClose()268 private synchronized void flushAndClose() throws SecurityException { 269 checkPermission(); 270 if (writer != null) { 271 try { 272 if (!doneHeader) { 273 writer.write(getFormatter().getHead(this)); 274 doneHeader = true; 275 } 276 writer.write(getFormatter().getTail(this)); 277 writer.flush(); 278 writer.close(); 279 } catch (Exception ex) { 280 // We don't want to throw an exception here, but we 281 // report the exception to any registered ErrorManager. 282 reportError(null, ex, ErrorManager.CLOSE_FAILURE); 283 } 284 writer = null; 285 output = null; 286 } 287 } 288 289 /** 290 * Close the current output stream. 291 * <p> 292 * The <tt>Formatter</tt>'s "tail" string is written to the stream before it 293 * is closed. In addition, if the <tt>Formatter</tt>'s "head" string has not 294 * yet been written to the stream, it will be written before the 295 * "tail" string. 296 * 297 * @exception SecurityException if a security manager exists and if 298 * the caller does not have LoggingPermission("control"). 299 */ 300 @Override close()301 public synchronized void close() throws SecurityException { 302 flushAndClose(); 303 } 304 } 305