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 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 {
35
36 protected ErrorHandler errorHandler;
37
38 public
39 QuietWriter(Writer writer, ErrorHandler errorHandler) {
40 super(writer);
41 setErrorHandler(errorHandler);
42 }
43
44 public
45 void write(String string) {
46 if (string != null) {
47 try {
48 out.write(string);
49 } catch(Exception e) {
50 errorHandler.error("Failed to write ["+string+"].", e,
51 ErrorCode.WRITE_FAILURE);
52 }
53 }
54 }
55
56 public
57 void flush() {
58 try {
59 out.flush();
60 } catch(Exception e) {
61 errorHandler.error("Failed to flush writer,", e,
62 ErrorCode.FLUSH_FAILURE);
63 }
64 }
65
66
67 public
68 void setErrorHandler(ErrorHandler eh) {
69 if(eh == null) {
70 // This is a programming error on the part of the enclosing appender.
71 throw new IllegalArgumentException("Attempted to set null ErrorHandler.");
72 } else {
73 this.errorHandler = eh;
74 }
75 }
76 }