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