1 /*
   2  * Copyright (c) 2000, 2012, 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 /**
  30  * This <tt>Handler</tt> publishes log records to <tt>System.err</tt>.
  31  * By default the <tt>SimpleFormatter</tt> is used to generate brief summaries.
  32  * <p>
  33  * <b>Configuration:</b>
  34  * By default each <tt>ConsoleHandler</tt> is initialized using the following
  35  * <tt>LogManager</tt> configuration properties where {@code <handler-name>}
  36  * refers to the fully-qualified class name of the handler.
  37  * If properties are not defined
  38  * (or have invalid values) then the specified default values are used.
  39  * <ul>
  40  * <li>   &lt;handler-name&gt;.level
  41  *        specifies the default level for the <tt>Handler</tt>
  42  *        (defaults to <tt>Level.INFO</tt>). </li>
  43  * <li>   &lt;handler-name&gt;.filter
  44  *        specifies the name of a <tt>Filter</tt> class to use
  45  *        (defaults to no <tt>Filter</tt>). </li>
  46  * <li>   &lt;handler-name&gt;.formatter
  47  *        specifies the name of a <tt>Formatter</tt> class to use
  48  *        (defaults to <tt>java.util.logging.SimpleFormatter</tt>). </li>
  49  * <li>   &lt;handler-name&gt;.encoding
  50  *        the name of the character set encoding to use (defaults to
  51  *        the default platform encoding). </li>
  52  * </ul>
  53  * <p>
  54  * For example, the properties for {@code ConsoleHandler} would be:
  55  * <ul>
  56  * <li>   java.util.logging.ConsoleHandler.level=INFO </li>
  57  * <li>   java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter </li>
  58  * </ul>
  59  * <p>
  60  * For a custom handler, e.g. com.foo.MyHandler, the properties would be:
  61  * <ul>
  62  * <li>   com.foo.MyHandler.level=INFO </li>
  63  * <li>   com.foo.MyHandler.formatter=java.util.logging.SimpleFormatter </li>
  64  * </ul>
  65  * <p>
  66  * @since 1.4
  67  */
  68 public class ConsoleHandler extends StreamHandler {
  69     // Private method to configure a ConsoleHandler from LogManager
  70     // properties and/or default values as specified in the class
  71     // javadoc.
  72     private void configure() {
  73         LogManager manager = LogManager.getLogManager();
  74         String cname = getClass().getName();
  75 
  76         setLevel(manager.getLevelProperty(cname +".level", Level.INFO));
  77         setFilter(manager.getFilterProperty(cname +".filter", null));
  78         setFormatter(manager.getFormatterProperty(cname +".formatter", new SimpleFormatter()));
  79         try {
  80             setEncoding(manager.getStringProperty(cname +".encoding", null));
  81         } catch (Exception ex) {
  82             try {
  83                 setEncoding(null);
  84             } catch (Exception ex2) {
  85                 // doing a setEncoding with null should always work.
  86                 // assert false;
  87             }
  88         }
  89     }
  90 
  91     /**
  92      * Create a <tt>ConsoleHandler</tt> for <tt>System.err</tt>.
  93      * <p>
  94      * The <tt>ConsoleHandler</tt> is configured based on
  95      * <tt>LogManager</tt> properties (or their default values).
  96      *
  97      */
  98     public ConsoleHandler() {
  99         sealed = false;
 100         configure();
 101         setOutputStream(System.err);
 102         sealed = true;
 103     }
 104 
 105     /**
 106      * Publish a <tt>LogRecord</tt>.
 107      * <p>
 108      * The logging request was made initially to a <tt>Logger</tt> object,
 109      * which initialized the <tt>LogRecord</tt> and forwarded it here.
 110      * <p>
 111      * @param  record  description of the log event. A null record is
 112      *                 silently ignored and is not published
 113      */
 114     @Override
 115     public void publish(LogRecord record) {
 116         super.publish(record);
 117         flush();
 118     }
 119 
 120     /**
 121      * Override <tt>StreamHandler.close</tt> to do a flush but not
 122      * to close the output stream.  That is, we do <b>not</b>
 123      * close <tt>System.err</tt>.
 124      */
 125     @Override
 126     public void close() {
 127         flush();
 128     }
 129 }
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