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Java > Open Source Codes > org > apache > log4j > helpers > QuietWriter


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.helpers;
18
19 import java.io.Writer JavaDoc;
20 import java.io.FilterWriter JavaDoc;
21 import java.io.IOException JavaDoc;
22 import org.apache.log4j.spi.ErrorHandler;
23 import org.apache.log4j.spi.ErrorCode;
24
25
26 /**
27    QuietWriter does not throw exceptions when things go
28    wrong. Instead, it delegates error handling to its {@link ErrorHandler}.
29
30    @author Ceki Gülcü
31
32    @since 0.7.3
33 */
34 public class QuietWriter extends FilterWriter JavaDoc {
35
36   protected ErrorHandler errorHandler;
37
38   public
39   QuietWriter(Writer JavaDoc writer, ErrorHandler errorHandler) {
40     super(writer);
41     setErrorHandler(errorHandler);
42   }
43
44   public
45   void write(String JavaDoc string) {
46     try {
47       out.write(string);
48     } catch(IOException JavaDoc e) {
49       errorHandler.error("Failed to write ["+string+"].", e,
50              ErrorCode.WRITE_FAILURE);
51     }
52   }
53
54   public
55   void flush() {
56     try {
57       out.flush();
58     } catch(IOException JavaDoc e) {
59       errorHandler.error("Failed to flush writer,", e,
60              ErrorCode.FLUSH_FAILURE);
61     }
62   }
63
64
65   public
66   void setErrorHandler(ErrorHandler eh) {
67     if(eh == null) {
68       // This is a programming error on the part of the enclosing appender.
69 throw new IllegalArgumentException JavaDoc("Attempted to set null ErrorHandler.");
70     } else {
71       this.errorHandler = eh;
72     }
73   }
74 }
75
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