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| 1 | /* | ||
| 2 | * Copyright (c) 2000, 2004, 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 java.util.logging; | ||
| 27 | |||
| 28 | /** | ||
| 29 | * <tt>Handler</tt> that buffers requests in a circular buffer in memory. | ||
| 30 | * <p> | ||
| 31 | * Normally this <tt>Handler</tt> simply stores incoming <tt>LogRecords</tt> | ||
| 32 | * into its memory buffer and discards earlier records. This buffering | ||
| 33 | * is very cheap and avoids formatting costs. On certain trigger | ||
| 34 | * conditions, the <tt>MemoryHandler</tt> will push out its current buffer | ||
| 35 | * contents to a target <tt>Handler</tt>, which will typically publish | ||
| 36 | * them to the outside world. | ||
| 37 | * <p> | ||
| 38 | * There are three main models for triggering a push of the buffer: | ||
| 39 | * <ul> | ||
| 40 | * <li> | ||
| 41 | * An incoming <tt>LogRecord</tt> has a type that is greater than | ||
| 42 | * a pre-defined level, the <tt>pushLevel</tt>. | ||
| 43 | * <li> | ||
| 44 | * An external class calls the <tt>push</tt> method explicitly. | ||
| 45 | * <li> | ||
| 46 | * A subclass overrides the <tt>log</tt> method and scans each incoming | ||
| 47 | * <tt>LogRecord</tt> and calls <tt>push</tt> if a record matches some | ||
| 48 | * desired criteria. | ||
| 49 | * </ul> | ||
| 50 | * <p> | ||
| 51 | * <b>Configuration:</b> | ||
| 52 | * By default each <tt>MemoryHandler</tt> is initialized using the following | ||
| 53 | * LogManager configuration properties. If properties are not defined | ||
| 54 | * (or have invalid values) then the specified default values are used. | ||
| 55 | * If no default value is defined then a RuntimeException is thrown. | ||
| 56 | * <ul> | ||
| 57 | * <li> java.util.logging.MemoryHandler.level | ||
| 58 | * specifies the level for the <tt>Handler</tt> | ||
| 59 | * (defaults to <tt>Level.ALL</tt>). | ||
| 60 | * <li> java.util.logging.MemoryHandler.filter | ||
| 61 | * specifies the name of a <tt>Filter</tt> class to use | ||
| 62 | * (defaults to no <tt>Filter</tt>). | ||
| 63 | * <li> java.util.logging.MemoryHandler.size | ||
| 64 | * defines the buffer size (defaults to 1000). | ||
| 65 | * <li> java.util.logging.MemoryHandler.push | ||
| 66 | * defines the <tt>pushLevel</tt> (defaults to <tt>level.SEVERE</tt>). | ||
| 67 | * <li> java.util.logging.MemoryHandler.target | ||
| 68 | * specifies the name of the target <tt>Handler </tt> class. | ||
| 69 | * (no default). | ||
| 70 | * </ul> | ||
| 71 | * | ||
| 72 | * @since 1.4 | ||
| 73 | */ | ||
| 74 | |||
| 75 | public class MemoryHandler extends Handler { | ||
| 76 | private final static int DEFAULT_SIZE = 1000; | ||
| 77 | private Level pushLevel; | ||
| 78 | private int size; | ||
| 79 | private Handler target; | ||
| 80 | private LogRecord buffer[]; | ||
| 81 | int start, count; | ||
| 82 | |||
| 83 | // Private method to configure a ConsoleHandler from LogManager | ||
| 84 | // properties and/or default values as specified in the class | ||
| 85 | // javadoc. | ||
| 86 | private void configure() { | ||
| 87 | LogManager manager = LogManager.getLogManager(); | ||
| 88 | String cname = getClass().getName(); | ||
| 89 | |||
| 90 | pushLevel = manager.getLevelProperty(cname +".push", Level.SEVERE); | ||
| 91 | size = manager.getIntProperty(cname + ".size", DEFAULT_SIZE); | ||
| 92 | if (size <= 0) { | ||
| 93 | size = DEFAULT_SIZE; | ||
| 94 | } | ||
| 95 | setLevel(manager.getLevelProperty(cname +".level", Level.ALL)); | ||
| 96 | setFilter(manager.getFilterProperty(cname +".filter", null)); | ||
| 97 | setFormatter(manager.getFormatterProperty(cname +".formatter", new SimpleFormatter())); | ||
| 98 | } | ||
| 99 | |||
| 100 | /** | ||
| 101 | * Create a <tt>MemoryHandler</tt> and configure it based on | ||
| 102 | * <tt>LogManager</tt> configuration properties. | ||
| 103 | */ | ||
| 104 | public MemoryHandler() { | ||
| 105 | sealed = false; | ||
| 106 | configure(); | ||
| 107 | sealed = true; | ||
| 108 | |||
| 109 | String name = "???"; | ||
| 110 | try { | ||
| 111 | LogManager manager = LogManager.getLogManager(); | ||
| 112 | name = manager.getProperty("java.util.logging.MemoryHandler.target"); | ||
| 113 | Class clz = ClassLoader.getSystemClassLoader().loadClass(name); | ||
| 114 | target = (Handler) clz.newInstance(); | ||
| 115 | } catch (Exception ex) { | ||
| 116 | throw new RuntimeException("MemoryHandler can't load handler \"" + name + "\"" , ex); | ||
| 117 | } | ||
| 118 | init(); | ||
| 119 | } | ||
| 120 | |||
| 121 | // Initialize. Size is a count of LogRecords. | ||
| 122 | private void init() { | ||
| 123 | buffer = new LogRecord[size]; | ||
| 124 | start = 0; | ||
| 125 | count = 0; | ||
| 126 | } | ||
| 127 | |||
| 128 | /** | ||
| 129 | * Create a <tt>MemoryHandler</tt>. | ||
| 130 | * <p> | ||
| 131 | * The <tt>MemoryHandler</tt> is configured based on <tt>LogManager</tt> | ||
| 132 | * properties (or their default values) except that the given <tt>pushLevel</tt> | ||
| 133 | * argument and buffer size argument are used. | ||
| 134 | * | ||
| 135 | * @param target the Handler to which to publish output. | ||
| 136 | * @param size the number of log records to buffer (must be greater than zero) | ||
| 137 | * @param pushLevel message level to push on | ||
| 138 | * | ||
| 139 | * @throws IllegalArgumentException if size is <= 0 | ||
| 140 | */ | ||
| 141 | public MemoryHandler(Handler target, int size, Level pushLevel) { | ||
| 142 | if (target == null || pushLevel == null) { | ||
| 143 | throw new NullPointerException(); | ||
| 144 | } | ||
| 145 | if (size <= 0) { | ||
| 146 | throw new IllegalArgumentException(); | ||
| 147 | } | ||
| 148 | sealed = false; | ||
| 149 | configure(); | ||
| 150 | sealed = true; | ||
| 151 | this.target = target; | ||
| 152 | this.pushLevel = pushLevel; | ||
| 153 | this.size = size; | ||
| 154 | init(); | ||
| 155 | } | ||
| 156 | |||
| 157 | /** | ||
| 158 | * Store a <tt>LogRecord</tt> in an internal buffer. | ||
| 159 | * <p> | ||
| 160 | * If there is a <tt>Filter</tt>, its <tt>isLoggable</tt> | ||
| 161 | * method is called to check if the given log record is loggable. | ||
| 162 | * If not we return. Otherwise the given record is copied into | ||
| 163 | * an internal circular buffer. Then the record's level property is | ||
| 164 | * compared with the <tt>pushLevel</tt>. If the given level is | ||
| 165 | * greater than or equal to the <tt>pushLevel</tt> then <tt>push</tt> | ||
| 166 | * is called to write all buffered records to the target output | ||
| 167 | * <tt>Handler</tt>. | ||
| 168 | * | ||
| 169 | * @param record description of the log event. A null record is | ||
| 170 | * silently ignored and is not published | ||
| 171 | */ | ||
| 172 | public synchronized void publish(LogRecord record) { | ||
| 173 | if (!isLoggable(record)) { | ||
| 174 | return; | ||
| 175 | } | ||
| 176 | int ix = (start+count)%buffer.length; | ||
| 177 | buffer[ix] = record; | ||
| 178 | if (count < buffer.length) { | ||
| 179 | count++; | ||
| 180 | } else { | ||
| 181 | start++; | ||
| 182 | start %= buffer.length; | ||
| 183 | } | ||
| 184 | if (record.getLevel().intValue() >= pushLevel.intValue()) { | ||
| 185 | push(); | ||
| 186 | } | ||
| 187 | } | ||
| 188 | |||
| 189 | /** | ||
| 190 | * Push any buffered output to the target <tt>Handler</tt>. | ||
| 191 | * <p> | ||
| 192 | * The buffer is then cleared. | ||
| 193 | */ | ||
| 194 | public synchronized void push() { | ||
| 195 | for (int i = 0; i < count; i++) { | ||
| 196 | int ix = (start+i)%buffer.length; | ||
| 197 | LogRecord record = buffer[ix]; | ||
| 198 | target.publish(record); | ||
| 199 | } | ||
| 200 | // Empty the buffer. | ||
| 201 | start = 0; | ||
| 202 | count = 0; | ||
| 203 | } | ||
| 204 | |||
| 205 | /** | ||
| 206 | * Causes a flush on the target <tt>Handler</tt>. | ||
| 207 | * <p> | ||
| 208 | * Note that the current contents of the <tt>MemoryHandler</tt> | ||
| 209 | * buffer are <b>not</b> written out. That requires a "push". | ||
| 210 | */ | ||
| 211 | public void flush() { | ||
| 212 | target.flush(); | ||
| 213 | } | ||
| 214 | |||
| 215 | /** | ||
| 216 | * Close the <tt>Handler</tt> and free all associated resources. | ||
| 217 | * This will also close the target <tt>Handler</tt>. | ||
| 218 | * | ||
| 219 | * @exception SecurityException if a security manager exists and if | ||
| 220 | * the caller does not have <tt>LoggingPermission("control")</tt>. | ||
| 221 | */ | ||
| 222 | public void close() throws SecurityException { | ||
| 223 | target.close(); | ||
| 224 | setLevel(Level.OFF); | ||
| 225 | } | ||
| 226 | |||
| 227 | /** | ||
| 228 | * Set the <tt>pushLevel</tt>. After a <tt>LogRecord</tt> is copied | ||
| 229 | * into our internal buffer, if its level is greater than or equal to | ||
| 230 | * the <tt>pushLevel</tt>, then <tt>push</tt> will be called. | ||
| 231 | * | ||
| 232 | * @param newLevel the new value of the <tt>pushLevel</tt> | ||
| 233 | * @exception SecurityException if a security manager exists and if | ||
| 234 | * the caller does not have <tt>LoggingPermission("control")</tt>. | ||
| 235 | */ | ||
| 236 | public void setPushLevel(Level newLevel) throws SecurityException { | ||
| 237 | if (newLevel == null) { | ||
| 238 | throw new NullPointerException(); | ||
| 239 | } | ||
| 240 | LogManager manager = LogManager.getLogManager(); | ||
| 241 | checkAccess(); | ||
| 242 | pushLevel = newLevel; | ||
| 243 | } | ||
| 244 | |||
| 245 | /** | ||
| 246 | * Get the <tt>pushLevel</tt>. | ||
| 247 | * | ||
| 248 | * @return the value of the <tt>pushLevel</tt> | ||
| 249 | */ | ||
| 250 | public synchronized Level getPushLevel() { | ||
| 251 | return pushLevel; | ||
| 252 | } | ||
| 253 | |||
| 254 | /** | ||
| 255 | * Check if this <tt>Handler</tt> would actually log a given | ||
| 256 | * <tt>LogRecord</tt> into its internal buffer. | ||
| 257 | * <p> | ||
| 258 | * This method checks if the <tt>LogRecord</tt> has an appropriate level and | ||
| 259 | * whether it satisfies any <tt>Filter</tt>. However it does <b>not</b> | ||
| 260 | * check whether the <tt>LogRecord</tt> would result in a "push" of the | ||
| 261 | * buffer contents. It will return false if the <tt>LogRecord</tt> is null. | ||
| 262 | * <p> | ||
| 263 | * @param record a <tt>LogRecord</tt> | ||
| 264 | * @return true if the <tt>LogRecord</tt> would be logged. | ||
| 265 | * | ||
| 266 | */ | ||
| 267 | public boolean isLoggable(LogRecord record) { | ||
| 268 | return super.isLoggable(record); | ||
| 269 | } | ||
| 270 | } | ||