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Java > Open Source Codes > org > apache > log4j > varia > NullAppender


1 /*
2  * Copyright 1999-2005 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.apache.log4j.varia;
18
19 import org.apache.log4j.Appender;
20 import org.apache.log4j.Layout;
21 import org.apache.log4j.spi.OptionHandler;
22 import org.apache.log4j.spi.LoggingEvent;
23 import org.apache.log4j.spi.ErrorHandler;
24 import org.apache.log4j.spi.Filter;
25 import org.apache.log4j.AppenderSkeleton;
26
27 /**
28   * A NullAppender merely exists, it never outputs a message to any
29   * device.
30   * @author Ceki Gülc¨
31   */
32 public class NullAppender extends AppenderSkeleton {
33
34   private static NullAppender instance = new NullAppender();
35
36   public NullAppender() {
37   }
38
39   /**
40    * There are no options to acticate.
41    * */
42   public void activateOptions() {
43   }
44
45   /**
46    * Whenever you can, use this method to retreive an instance instead
47    * of instantiating a new one with <code>new</code>.
48    * */
49   public NullAppender getInstance() {
50     return instance;
51   }
52
53   public void close() {
54   }
55
56   /**
57    * Does not do anything.
58    * */
59   public void doAppend(LoggingEvent event) {
60   }
61
62   /**
63    * Does not do anything.
64    * */
65   protected void append(LoggingEvent event) {
66   }
67
68   /**
69     * NullAppenders do not need a layout.
70     * */
71   public boolean requiresLayout() {
72     return false;
73   }
74 }
75
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