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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/SocketInputBuffer.java $
      3  * $Revision: 560358 $
      4  * $Date: 2007-07-27 12:30:42 -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.InterruptedIOException;
     36 import java.net.Socket;
     37 
     38 import org.apache.http.params.HttpParams;
     39 
     40 
     41 /**
     42  * {@link Socket} bound session input buffer.
     43  *
     44  * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
     45  *
     46  * @version $Revision: 560358 $
     47  *
     48  * @since 4.0
     49  */
     50 public class SocketInputBuffer extends AbstractSessionInputBuffer {
     51 
     52     static private final Class SOCKET_TIMEOUT_CLASS = SocketTimeoutExceptionClass();
     53 
     54     /**
     55      * Returns <code>SocketTimeoutExceptionClass<code> or <code>null</code> if the class
     56      * does not exist.
     57      *
     58      * @return <code>SocketTimeoutExceptionClass<code>, or <code>null</code> if unavailable.
     59      */
     60     static private Class SocketTimeoutExceptionClass() {
     61         try {
     62             return Class.forName("java.net.SocketTimeoutException");
     63         } catch (ClassNotFoundException e) {
     64             return null;
     65         }
     66     }
     67 
     68     private static boolean isSocketTimeoutException(final InterruptedIOException e) {
     69         if (SOCKET_TIMEOUT_CLASS != null) {
     70             return SOCKET_TIMEOUT_CLASS.isInstance(e);
     71         } else {
     72             return true;
     73         }
     74     }
     75 
     76     private final Socket socket;
     77 
     78     public SocketInputBuffer(
     79             final Socket socket,
     80             int buffersize,
     81             final HttpParams params) throws IOException {
     82         super();
     83         if (socket == null) {
     84             throw new IllegalArgumentException("Socket may not be null");
     85         }
     86         this.socket = socket;
     87         if (buffersize < 0) {
     88             buffersize = socket.getReceiveBufferSize();
     89         }
     90         if (buffersize < 1024) {
     91             buffersize = 1024;
     92         }
     93         init(socket.getInputStream(), buffersize, params);
     94     }
     95 
     96     public boolean isDataAvailable(int timeout) throws IOException {
     97         boolean result = hasBufferedData();
     98         if (!result) {
     99             int oldtimeout = this.socket.getSoTimeout();
    100             try {
    101                 this.socket.setSoTimeout(timeout);
    102                 fillBuffer();
    103                 result = hasBufferedData();
    104             } catch (InterruptedIOException e) {
    105                 if (!isSocketTimeoutException(e)) {
    106                     throw e;
    107                 }
    108             } finally {
    109                 socket.setSoTimeout(oldtimeout);
    110             }
    111         }
    112         return result;
    113     }
    114 
    115 }
    116