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      1 /*
      2  * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/impl/io/ContentLengthOutputStream.java $
      3  * $Revision: 560343 $
      4  * $Date: 2007-07-27 11:18:19 -0700 (Fri, 27 Jul 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.impl.io;
     33 
     34 import java.io.IOException;
     35 import java.io.OutputStream;
     36 
     37 import org.apache.http.io.SessionOutputBuffer;
     38 
     39 /**
     40  * A stream wrapper that closes itself after a defined number of bytes.
     41  *
     42  * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
     43  *
     44  * @version $Revision: 560343 $
     45  *
     46  * @since 4.0
     47  */
     48 public class ContentLengthOutputStream extends OutputStream {
     49 
     50     /**
     51      * Wrapped session outbut buffer.
     52      */
     53     private final SessionOutputBuffer out;
     54 
     55     /**
     56      * The maximum number of bytes that can be written the stream. Subsequent
     57      * write operations will be ignored.
     58      */
     59     private final long contentLength;
     60 
     61     /** Total bytes written */
     62     private long total = 0;
     63 
     64     /** True if the stream is closed. */
     65     private boolean closed = false;
     66 
     67     /**
     68      * Creates a new length limited stream
     69      *
     70      * @param out The data transmitter to wrap
     71      * @param contentLength The maximum number of bytes that can be written to
     72      * the stream. Subsequent write operations will be ignored.
     73      *
     74      * @since 4.0
     75      */
     76     public ContentLengthOutputStream(final SessionOutputBuffer out, long contentLength) {
     77         super();
     78         if (out == null) {
     79             throw new IllegalArgumentException("Session output buffer may not be null");
     80         }
     81         if (contentLength < 0) {
     82             throw new IllegalArgumentException("Content length may not be negative");
     83         }
     84         this.out = out;
     85         this.contentLength = contentLength;
     86     }
     87 
     88     /**
     89      * <p>Does not close the underlying socket output.</p>
     90      *
     91      * @throws IOException If an I/O problem occurs.
     92      */
     93     public void close() throws IOException {
     94         if (!this.closed) {
     95             this.closed = true;
     96             this.out.flush();
     97         }
     98     }
     99 
    100     public void flush() throws IOException {
    101         this.out.flush();
    102     }
    103 
    104     public void write(byte[] b, int off, int len) throws IOException {
    105         if (this.closed) {
    106             throw new IOException("Attempted write to closed stream.");
    107         }
    108         if (this.total < this.contentLength) {
    109             long max = this.contentLength - this.total;
    110             if (len > max) {
    111                 len = (int) max;
    112             }
    113             this.out.write(b, off, len);
    114             this.total += len;
    115         }
    116     }
    117 
    118     public void write(byte[] b) throws IOException {
    119         write(b, 0, b.length);
    120     }
    121 
    122     public void write(int b) throws IOException {
    123         if (this.closed) {
    124             throw new IOException("Attempted write to closed stream.");
    125         }
    126         if (this.total < this.contentLength) {
    127             this.out.write(b);
    128             this.total++;
    129         }
    130     }
    131 
    132 }
    133