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 package org.apache.logging.log4j.core.appender;
18
19 import java.io.BufferedOutputStream;
20 import java.io.File;
21 import java.io.FileNotFoundException;
22 import java.io.FileOutputStream;
23 import java.io.IOException;
24 import java.io.OutputStream;
25 import java.nio.channels.FileChannel;
26 import java.nio.channels.FileLock;
27
28
29 /**
30 * Manages actual File I/O for File Appenders.
31 */
32 public class FileManager extends OutputStreamManager {
33
34 private static final FileManagerFactory factory = new FileManagerFactory();
35
36 private final boolean isAppend;
37 private final boolean isLocking;
38
39 protected FileManager(String fileName, OutputStream os, boolean append, boolean locking) {
40 super(os, fileName);
41 this.isAppend = append;
42 this.isLocking = locking;
43 }
44
45 /**
46 * Returns the FileManager.
47 * @param fileName The name of the file to manage.
48 * @param append true if the file should be appended to, false if it should be overwritten.
49 * @param locking true if the file should be locked while writing, false otherwise.
50 * @param bufferedIO true if the contents should be buffered as they are written.
51 * @return A FileManager for the File.
52 */
53 public static FileManager getFileManager(String fileName, boolean append, boolean locking, boolean bufferedIO) {
54
55 if (locking && bufferedIO) {
56 locking = false;
57 }
58 return (FileManager) getManager(fileName, new FactoryData(append, locking, bufferedIO), factory);
59 }
60
61 @Override
62 protected synchronized void write(byte[] bytes, int offset, int length) {
63
64 if (isLocking) {
65 FileChannel channel = ((FileOutputStream) getOutputStream()).getChannel();
66 try {
67 /* Lock the whole file. This could be optimized to only lock from the current file
68 position. Note that locking may be advisory on some systems and mandatory on others,
69 so locking just from the current position would allow reading on systems where
70 locking is mandatory. Also, Java 6 will throw an exception if the region of the
71 file is already locked by another FileChannel in the same JVM. Hopefully, that will
72 be avoided since every file should have a single file manager - unless two different
73 files strings are configured that somehow map to the same file.*/
74 FileLock lock = channel.lock(0, Long.MAX_VALUE, false);
75 try {
76 super.write(bytes, offset, length);
77 } finally {
78 lock.release();
79 }
80 } catch (IOException ex) {
81 throw new AppenderRuntimeException("Unable to obtain lock on " + getName(), ex);
82 }
83
84 } else {
85 super.write(bytes, offset, length);
86 }
87 }
88
89 /**
90 * Returns the name of the File being managed.
91 * @return The name of the File being managed.
92 */
93 public String getFileName() {
94 return getName();
95 }
96
97 /**
98 * Returns the append status.
99 * @return true if the file will be appended to, false if it is overwritten.
100 */
101 public boolean isAppend() {
102 return isAppend;
103 }
104
105 /**
106 * Returns the lock status.
107 * @return true if the file will be locked when writing, false otherwise.
108 */
109 public boolean isLocking() {
110 return isLocking;
111 }
112
113 /**
114 * Factory Data.
115 */
116 private static class FactoryData {
117 private final boolean append;
118 private final boolean locking;
119 private final boolean bufferedIO;
120
121 /**
122 * Constructor.
123 * @param append Append status.
124 * @param locking Locking status.
125 * @param bufferedIO Buffering flag.
126 */
127 public FactoryData(boolean append, boolean locking, boolean bufferedIO) {
128 this.append = append;
129 this.locking = locking;
130 this.bufferedIO = bufferedIO;
131 }
132 }
133
134 /**
135 * Factory to create a FileManager.
136 */
137 private static class FileManagerFactory implements ManagerFactory<FileManager, FactoryData> {
138
139 /**
140 * Create a FileManager.
141 * @param name The name of the File.
142 * @param data The FactoryData
143 * @return The FileManager for the File.
144 */
145 public FileManager createManager(String name, FactoryData data) {
146 File file = new File(name);
147 final File parent = file.getParentFile();
148 if (null != parent && !parent.exists()) {
149 parent.mkdirs();
150 }
151
152 OutputStream os;
153 try {
154 os = new FileOutputStream(name, data.append);
155 if (data.bufferedIO) {
156 os = new BufferedOutputStream(os);
157 }
158 return new FileManager(name, os, data.append, data.locking);
159 } catch (FileNotFoundException ex) {
160 LOGGER.error("FileManager (" + name + ") " + ex);
161 }
162 return null;
163 }
164 }
165
166 }