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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  
28  package org.apache.http.entity;
29  
30  import java.io.ByteArrayInputStream;
31  import java.io.ByteArrayOutputStream;
32  import java.io.IOException;
33  import java.io.InputStream;
34  import java.io.OutputStream;
35  
36  import org.apache.http.HttpEntity;
37  import org.apache.http.annotation.NotThreadSafe;
38  import org.apache.http.util.Args;
39  
40  /**
41   * A wrapping entity that buffers it content if necessary.
42   * The buffered entity is always repeatable.
43   * If the wrapped entity is repeatable itself, calls are passed through.
44   * If the wrapped entity is not repeatable, the content is read into a
45   * buffer once and provided from there as often as required.
46   *
47   * @since 4.0
48   */
49  @NotThreadSafe
50  public class BufferedHttpEntity extends HttpEntityWrapper {
51  
52      private final byte[] buffer;
53  
54      /**
55       * Creates a new buffered entity wrapper.
56       *
57       * @param entity   the entity to wrap, not null
58       * @throws IllegalArgumentException if wrapped is null
59       */
60      public BufferedHttpEntity(final HttpEntity entity) throws IOException {
61          super(entity);
62          if (!entity.isRepeatable() || entity.getContentLength() < 0) {
63              final ByteArrayOutputStream out = new ByteArrayOutputStream();
64              entity.writeTo(out);
65              out.flush();
66              this.buffer = out.toByteArray();
67          } else {
68              this.buffer = null;
69          }
70      }
71  
72      @Override
73      public long getContentLength() {
74          if (this.buffer != null) {
75              return this.buffer.length;
76          } else {
77              return super.getContentLength();
78          }
79      }
80  
81      @Override
82      public InputStream getContent() throws IOException {
83          if (this.buffer != null) {
84              return new ByteArrayInputStream(this.buffer);
85          } else {
86              return super.getContent();
87          }
88      }
89  
90      /**
91       * Tells that this entity does not have to be chunked.
92       *
93       * @return  {@code false}
94       */
95      @Override
96      public boolean isChunked() {
97          return (buffer == null) && super.isChunked();
98      }
99  
100     /**
101      * Tells that this entity is repeatable.
102      *
103      * @return  {@code true}
104      */
105     @Override
106     public boolean isRepeatable() {
107         return true;
108     }
109 
110 
111     @Override
112     public void writeTo(final OutputStream outstream) throws IOException {
113         Args.notNull(outstream, "Output stream");
114         if (this.buffer != null) {
115             outstream.write(this.buffer);
116         } else {
117             super.writeTo(outstream);
118         }
119     }
120 
121 
122     // non-javadoc, see interface HttpEntity
123     @Override
124     public boolean isStreaming() {
125         return (buffer == null) && super.isStreaming();
126     }
127 
128 } // class BufferedHttpEntity