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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  package org.apache.http.client.entity;
28  
29  import java.io.IOException;
30  import java.io.InputStream;
31  import java.io.OutputStream;
32  
33  import org.apache.http.HttpEntity;
34  import org.apache.http.entity.HttpEntityWrapper;
35  import org.apache.http.util.Args;
36  
37  /**
38   * Common base class for decompressing {@link HttpEntity} implementations.
39   *
40   * @since 4.1
41   */
42  abstract class DecompressingEntity extends HttpEntityWrapper {
43  
44      /**
45       * Default buffer size.
46       */
47      private static final int BUFFER_SIZE = 1024 * 2;
48  
49      /**
50       * {@link #getContent()} method must return the same {@link InputStream}
51       * instance when DecompressingEntity is wrapping a streaming entity.
52       */
53      private InputStream content;
54  
55      /**
56       * Creates a new {@link DecompressingEntity}.
57       *
58       * @param wrapped
59       *            the non-null {@link HttpEntity} to be wrapped
60       */
61      public DecompressingEntity(final HttpEntity wrapped) {
62          super(wrapped);
63      }
64  
65      abstract InputStream decorate(final InputStream wrapped) throws IOException;
66  
67      private InputStream getDecompressingStream() throws IOException {
68          final InputStream in = wrappedEntity.getContent();
69          return new LazyDecompressingInputStream(in, this);
70      }
71  
72      /**
73       * {@inheritDoc}
74       */
75      @Override
76      public InputStream getContent() throws IOException {
77          if (wrappedEntity.isStreaming()) {
78              if (content == null) {
79                  content = getDecompressingStream();
80              }
81              return content;
82          } else {
83              return getDecompressingStream();
84          }
85      }
86  
87      /**
88       * {@inheritDoc}
89       */
90      @Override
91      public void writeTo(final OutputStream outstream) throws IOException {
92          Args.notNull(outstream, "Output stream");
93          final InputStream instream = getContent();
94          try {
95              final byte[] buffer = new byte[BUFFER_SIZE];
96              int l;
97              while ((l = instream.read(buffer)) != -1) {
98                  outstream.write(buffer, 0, l);
99              }
100         } finally {
101             instream.close();
102         }
103     }
104 
105 }