WriterTarget


1   /*
2    * Copyright (C) The Apache Software Foundation. All rights reserved.
3    *
4    * This software is published under the terms of the Apache Software License
5    * version 1.1, a copy of which has been included with this distribution in
6    * the LICENSE file.
7    */
8   package org.jivesoftware.util.log.output.io;
9   
10  import org.jivesoftware.util.log.format.Formatter;
11  import org.jivesoftware.util.log.output.AbstractOutputTarget;
12  import java.io.IOException  ;
13  import java.io.Writer  ;
14  
15  /**
16   * This target outputs to a writer.
17   *
18   * @author <a HREF="mailto:peter@apache.org">Peter Donald</a>
19   */
20  public class WriterTarget extends AbstractOutputTarget {
21  
22      private Writer   m_output;
23  
24      /**
25       * Construct target with a specific writer and formatter.
26       *
27       * @param writer    the writer
28       * @param formatter the formatter
29       */
30      public WriterTarget(final Writer   writer, final Formatter formatter) {
31          super(formatter);
32  
33          if (null != writer) {
34              setWriter(writer);
35              open();
36          }
37      }
38  
39      /**
40       * Set the writer.
41       * Close down writer and send tail if appropriate.
42       *
43       * @param writer the new writer
44       */
45      protected synchronized void setWriter(final Writer   writer) {
46          if (null == writer) {
47              throw new NullPointerException  ("writer property must not be null");
48          }
49  
50          m_output = writer;
51      }
52  
53      /**
54       * Concrete implementation of output that writes out to underlying writer.
55       *
56       * @param data the data to output
57       */
58      protected void write(final String   data) {
59          try {
60              m_output.write(data);
61              m_output.flush();
62          }
63          catch (final IOException   ioe) {
64              getErrorHandler().error("Caught an IOException", ioe, null);
65          }
66      }
67  
68      /**
69       * Shutdown target.
70       * Attempting to send to target after close() will cause errors to be logged.
71       */
72      public synchronized void close() {
73          super.close();
74          shutdownWriter();
75      }
76  
77      /**
78       * Shutdown Writer.
79       */
80      protected synchronized void shutdownWriter() {
81          final Writer   writer = m_output;
82          m_output = null;
83  
84          try {
85              if (null != writer) {
86                  writer.close();
87              }
88          }
89          catch (final IOException   ioe) {
90              getErrorHandler().error("Error closing Writer", ioe, null);
91          }
92      }
93  }
94
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