BUnzip2


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  
19  package org.apache.tools.ant.taskdefs;
20  
21  
22  import java.io.BufferedInputStream  ;
23  import java.io.FileOutputStream  ;
24  import java.io.IOException  ;
25  import java.io.InputStream  ;
26  import org.apache.tools.ant.BuildException;
27  import org.apache.tools.ant.util.FileUtils;
28  import org.apache.tools.bzip2.CBZip2InputStream;
29  
30  /**
31   * Expands a file that has been compressed with the BZIP2
32   * algorithm. Normally used to compress non-compressed archives such
33   * as TAR files.
34   *
35   * @since Ant 1.5
36   *
37   * @ant.task category="packaging"
38   */
39  
40  public class BUnzip2 extends Unpack {
41  
42      private static final String   DEFAULT_EXTENSION = ".bz2";
43  
44      /**
45       * Get the default extension.
46       * @return the string ".bz2"
47       */
48      protected String   getDefaultExtension() {
49          return DEFAULT_EXTENSION;
50      }
51  
52      /**
53       * Do the unbzipping.
54       */
55      protected void extract() {
56          if (source.lastModified() > dest.lastModified()) {
57              log("Expanding " + source.getAbsolutePath() + " to "
58                  + dest.getAbsolutePath());
59  
60              FileOutputStream   out = null;
61              CBZip2InputStream zIn = null;
62              InputStream   fis = null;
63              BufferedInputStream   bis = null;
64              try {
65                  out = new FileOutputStream  (dest);
66                  fis = srcResource.getInputStream();
67                  bis = new BufferedInputStream  (fis);
68                  int b = bis.read();
69                  if (b != 'B') {
70                      throw new BuildException("Invalid bz2 file.", getLocation());
71                  }
72                  b = bis.read();
73                  if (b != 'Z') {
74                      throw new BuildException("Invalid bz2 file.", getLocation());
75                  }
76                  zIn = new CBZip2InputStream(bis);
77                  byte[] buffer = new byte[8 * 1024];
78                  int count = 0;
79                  do {
80                      out.write(buffer, 0, count);
81                      count = zIn.read(buffer, 0, buffer.length);
82                  } while (count != -1);
83              } catch (IOException   ioe) {
84                  String   msg = "Problem expanding bzip2 " + ioe.getMessage();
85                  throw new BuildException(msg, ioe, getLocation());
86              } finally {
87                  FileUtils.close(bis);
88                  FileUtils.close(fis);
89                  FileUtils.close(out);
90                  FileUtils.close(zIn);
91              }
92          }
93      }
94  
95      /**
96       * Whether this task can deal with non-file resources.
97       *
98       * <p>This implementation returns true only if this task is
99       * &lt;gunzip&gt;.  Any subclass of this class that also wants to
100      * support non-file resources needs to override this method.  We
101      * need to do so for backwards compatibility reasons since we
102      * can't expect subclasses to support resources.</p>
103      * @return true if this class supports non file resources.
104      * @since Ant 1.7
105      */
106     protected boolean supportsNonFileResources() {
107         return getClass().equals(BUnzip2.class);
108     }
109 }
110
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