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      1 /*
      2  * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/entity/BasicHttpEntity.java $
      3  * $Revision: 496070 $
      4  * $Date: 2007-01-14 04:18:34 -0800 (Sun, 14 Jan 2007) $
      5  *
      6  * ====================================================================
      7  * Licensed to the Apache Software Foundation (ASF) under one
      8  * or more contributor license agreements.  See the NOTICE file
      9  * distributed with this work for additional information
     10  * regarding copyright ownership.  The ASF licenses this file
     11  * to you under the Apache License, Version 2.0 (the
     12  * "License"); you may not use this file except in compliance
     13  * with the License.  You may obtain a copy of the License at
     14  *
     15  *   http://www.apache.org/licenses/LICENSE-2.0
     16  *
     17  * Unless required by applicable law or agreed to in writing,
     18  * software distributed under the License is distributed on an
     19  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
     20  * KIND, either express or implied.  See the License for the
     21  * specific language governing permissions and limitations
     22  * under the License.
     23  * ====================================================================
     24  *
     25  * This software consists of voluntary contributions made by many
     26  * individuals on behalf of the Apache Software Foundation.  For more
     27  * information on the Apache Software Foundation, please see
     28  * <http://www.apache.org/>.
     29  *
     30  */
     31 
     32 package org.apache.http.entity;
     33 
     34 import java.io.IOException;
     35 import java.io.InputStream;
     36 import java.io.OutputStream;
     37 
     38 /**
     39  * A generic streamed entity being received on a connection.
     40  *
     41  * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
     42  *
     43  * @version $Revision: 496070 $
     44  *
     45  * @since 4.0
     46  */
     47 public class BasicHttpEntity extends AbstractHttpEntity {
     48 
     49     private InputStream content;
     50     private boolean contentObtained;
     51     private long length;
     52 
     53     /**
     54      * Creates a new basic entity.
     55      * The content is initially missing, the content length
     56      * is set to a negative number.
     57      */
     58     public BasicHttpEntity() {
     59         super();
     60         this.length = -1;
     61     }
     62 
     63     // non-javadoc, see interface HttpEntity
     64     public long getContentLength() {
     65         return this.length;
     66     }
     67 
     68     /**
     69      * Obtains the content, once only.
     70      *
     71      * @return  the content, if this is the first call to this method
     72      *          since {@link #setContent setContent} has been called
     73      *
     74      * @throws IllegalStateException
     75      *          if the content has been obtained before, or
     76      *          has not yet been provided
     77      */
     78     public InputStream getContent()
     79         throws IllegalStateException {
     80         if (this.content == null) {
     81             throw new IllegalStateException("Content has not been provided");
     82         }
     83         if (this.contentObtained) {
     84             throw new IllegalStateException("Content has been consumed");
     85         }
     86         this.contentObtained = true;
     87         return this.content;
     88 
     89     } // getContent
     90 
     91     /**
     92      * Tells that this entity is not repeatable.
     93      *
     94      * @return <code>false</code>
     95      */
     96     public boolean isRepeatable() {
     97         return false;
     98     }
     99 
    100     /**
    101      * Specifies the length of the content.
    102      *
    103      * @param len       the number of bytes in the content, or
    104      *                  a negative number to indicate an unknown length
    105      */
    106     public void setContentLength(long len) {
    107         this.length = len;
    108     }
    109 
    110     /**
    111      * Specifies the content.
    112      *
    113      * @param instream          the stream to return with the next call to
    114      *                          {@link #getContent getContent}
    115      */
    116     public void setContent(final InputStream instream) {
    117         this.content = instream;
    118         this.contentObtained = false;
    119     }
    120 
    121     // non-javadoc, see interface HttpEntity
    122     public void writeTo(final OutputStream outstream) throws IOException {
    123         if (outstream == null) {
    124             throw new IllegalArgumentException("Output stream may not be null");
    125         }
    126         InputStream instream = getContent();
    127         int l;
    128         byte[] tmp = new byte[2048];
    129         while ((l = instream.read(tmp)) != -1) {
    130             outstream.write(tmp, 0, l);
    131         }
    132     }
    133 
    134     // non-javadoc, see interface HttpEntity
    135     public boolean isStreaming() {
    136         return !this.contentObtained && this.content != null;
    137     }
    138 
    139     // non-javadoc, see interface HttpEntity
    140     public void consumeContent() throws IOException {
    141         if (content != null) {
    142             content.close(); // reads to the end of the entity
    143         }
    144     }
    145 
    146 } // class BasicHttpEntity
    147