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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.log4j.helpers;
19  
20  import java.io.Writer;
21  import java.io.FilterWriter;
22  import java.io.IOException;
23  import org.apache.log4j.spi.ErrorHandler;
24  import org.apache.log4j.spi.ErrorCode;
25  
26  
27  /***
28     QuietWriter does not throw exceptions when things go
29     wrong. Instead, it delegates error handling to its {@link ErrorHandler}. 
30  
31     @author Ceki Gülcü
32  
33     @since 0.7.3
34  */
35  public class QuietWriter extends FilterWriter {
36  
37    protected ErrorHandler errorHandler;
38  
39    public
40    QuietWriter(Writer writer, ErrorHandler errorHandler) {
41      super(writer);
42      setErrorHandler(errorHandler);
43    }
44  
45    public
46    void write(String string) {
47      try {
48        out.write(string);
49      } catch(IOException e) {
50        errorHandler.error("Failed to write ["+string+"].", e, 
51  			 ErrorCode.WRITE_FAILURE);
52      }
53    }
54  
55    public
56    void flush() {
57      try {
58        out.flush();
59      } catch(IOException e) {
60        errorHandler.error("Failed to flush writer,", e, 
61  			 ErrorCode.FLUSH_FAILURE);
62      }	
63    }
64  
65  
66    public
67    void setErrorHandler(ErrorHandler eh) {
68      if(eh == null) {
69        // This is a programming error on the part of the enclosing appender.
70        throw new IllegalArgumentException("Attempted to set null ErrorHandler.");
71      } else { 
72        this.errorHandler = eh;
73      }
74    }
75  }