odk/examples/DevelopersGuide/UCB/MyInputStream.java

   1 /*************************************************************************
   2  *
   3  *  $RCSfile: MyInputStream.java,v $
   4  *
   5  *  $Revision: 1.5 $
   6  *
   7  *  last change: $Author: rt $ $Date: 2005-01-31 16:58:25 $
   8  *
   9  *  The Contents of this file are made available subject to the terms of
  10  *  the BSD license.
  11  *
  12  *  Copyright (c) 2003 by Sun Microsystems, Inc.
  13  *  All rights reserved.
  14  *
  15  *  Redistribution and use in source and binary forms, with or without
  16  *  modification, are permitted provided that the following conditions
  17  *  are met:
  18  *  1. Redistributions of source code must retain the above copyright
  19  *     notice, this list of conditions and the following disclaimer.
  20  *  2. Redistributions in binary form must reproduce the above copyright
  21  *     notice, this list of conditions and the following disclaimer in the
  22  *     documentation and/or other materials provided with the distribution.
  23  *  3. Neither the name of Sun Microsystems, Inc. nor the names of its
  24  *     contributors may be used to endorse or promote products derived
  25  *     from this software without specific prior written permission.
  26  *
  27  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30  *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31  *  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33  *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
  34  *  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  35  *  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
  36  *  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
  37  *  USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  38  *
  39  *************************************************************************/
  40
  41 // imports
  42 import com.sun.star.io.BufferSizeExceededException;
  43 import com.sun.star.io.NotConnectedException;
  44 import com.sun.star.io.XInputStream;
  45 import com.sun.star.io.XSeekable;
  46
  47 /**
  48  * XInputStream interface implementation.
  49  */
  50 public class MyInputStream implements XSeekable, XInputStream {
  51
  52     /**
  53      * Member properties
  54      */
  55     private int offset = 0;
  56     private int read = offset;
  57     private byte[] bigbuffer;
  58
  59     /**
  60      * Constructor
  61      */
  62     public MyInputStream() {
  63     }
  64
  65         // XSeekable. Makes it possible to seek to a certain position within a stream.
  66
  67     /**
  68      *   Returns the length of the stream.
  69      *
  70      *@return  long  The length of the storage medium on which the stream works.
  71      */
  72     public synchronized long getLength()
  73         throws com.sun.star.io.IOException,com.sun.star.uno.RuntimeException {
  74         if ( bigbuffer != null ) {
  75             return bigbuffer.length - offset;
  76         } else {
  77             return 0;
  78         }
  79     }
  80
  81     /**
  82      *   Returns the current offset of the stream.
  83      *
  84      *@return  long  The current offset in this stream.
  85      */
  86     public synchronized long getPosition()
  87         throws com.sun.star.io.IOException,com.sun.star.uno.RuntimeException {
  88         return read - offset ;
  89     }
  90
  91     /**
  92      *  Changes the seek pointer to a new location relative to the beginning of the stream.
  93      *
  94      *@param  long
  95      */
  96     public synchronized void seek(long p0)
  97         throws IllegalArgumentException, com.sun.star.io.IOException,
  98             com.sun.star.uno.RuntimeException {
  99         if( bigbuffer != null ) {
 100             p0 +=offset;
 101             read = ( int ) p0;
 102             if( read < offset || read > bigbuffer.length )
 103                 throw new IllegalArgumentException();
 104         }
 105     }
 106
 107         // XInputStream. This is the basic interface to read data from a stream.
 108
 109     /**
 110      *   States how many bytes can be read or skipped without blocking.
 111      *
 112      *@return  int  If not available, then returned 0
 113      */
 114     public synchronized int available()
 115         throws NotConnectedException, com.sun.star.io.IOException,
 116             com.sun.star.uno.RuntimeException {
 117         if( bigbuffer != null )
 118             return ( bigbuffer.length - read );
 119         else
 120             return 0;
 121     }
 122
 123     /**
 124      *   Closes the stream. .
 125      */
 126     public void closeInput()
 127         throws NotConnectedException,com.sun.star.io.IOException,
 128         com.sun.star.uno.RuntimeException {
 129         read = -1;
 130     }
 131
 132     /**
 133      *   Reads the specified number of bytes in the given sequence.
 134      *
 135      *@param    byte[][]
 136      *@param    int
 137      *@return   int
 138      */
 139     public synchronized int readBytes(byte[][] p0, int p1)
 140         throws NotConnectedException, BufferSizeExceededException,
 141             com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
 142         if( bigbuffer != null ) {
 143             if( read == -1 )
 144                   return 0;
 145             int i = 0;
 146             int available;
 147             if ( p1 > bigbuffer.length - read )
 148                 available = bigbuffer.length - read;
 149             else
 150                 available = p1;
 151
 152             p0[0] = new byte[p1];
 153             while( available != 0 ) {
 154                 p0[0][i++] = bigbuffer[read++];
 155                 --available;
 156             }
 157             return i;
 158         } else {
 159             p0[0] = new byte[0];
 160             return 0;
 161         }
 162     }
 163
 164     /**
 165      *  Reads the available number of bytes at maximum  nMaxBytesToRead .
 166      *  This method blocks the thread until at least one byte is available.
 167      *
 168      *@param    byte[][]
 169      *@param    int
 170      *@return   int
 171      */
 172     public synchronized int readSomeBytes(byte[][] p0, int p1)
 173             throws      NotConnectedException,
 174                     BufferSizeExceededException,
 175                     com.sun.star.io.IOException,
 176                     com.sun.star.uno.RuntimeException {
 177             return readBytes( p0,p1 );
 178     }
 179
 180     /**
 181      *  Skips the next nBytesToSkip bytes (must be positive).
 182      *  It is up to the implementation whether this method is blocking the thread or not.
 183      *
 184      *@param    int
 185      */
 186     public synchronized void skipBytes(int p0)
 187         throws  NotConnectedException, BufferSizeExceededException,
 188             com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
 189         read += p0;
 190         if( read > bigbuffer.length )
 191             read = bigbuffer.length;
 192
 193         if( read < offset )
 194             read = offset;
 195     }
 196 }