odk/examples/DevelopersGuide/UCB/MyInputStream.java

   1 /* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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  35
  36 import com.sun.star.io.BufferSizeExceededException;
  37 import com.sun.star.io.NotConnectedException;
  38 import com.sun.star.io.XInputStream;
  39 import com.sun.star.io.XSeekable;
  40
  41 /**
  42  * XInputStream interface implementation.
  43  */
  44 public class MyInputStream implements XSeekable, XInputStream {
  45
  46     /**
  47      * Member properties
  48      */
  49     private int offset = 0;
  50     private int read = offset;
  51     private byte[] bigbuffer;
  52
  53     /**
  54      * Constructor
  55      */
  56     public MyInputStream() {
  57     }
  58
  59         // XSeekable. Makes it possible to seek to a certain position within a stream.
  60
  61     /**
  62      *   Returns the length of the stream.
  63      *
  64      *@return  long  The length of the storage medium on which the stream works.
  65      */
  66     public synchronized long getLength()
  67         throws com.sun.star.io.IOException,com.sun.star.uno.RuntimeException {
  68         if ( bigbuffer != null ) {
  69             return bigbuffer.length - offset;
  70         } else {
  71             return 0;
  72         }
  73     }
  74
  75     /**
  76      *   Returns the current offset of the stream.
  77      *
  78      *@return  long  The current offset in this stream.
  79      */
  80     public synchronized long getPosition()
  81         throws com.sun.star.io.IOException,com.sun.star.uno.RuntimeException {
  82         return read - offset ;
  83     }
  84
  85     /**
  86      *  Changes the seek pointer to a new location relative to the beginning of the stream.
  87      */
  88     public synchronized void seek(long p0)
  89         throws IllegalArgumentException, com.sun.star.io.IOException,
  90             com.sun.star.uno.RuntimeException {
  91         if( bigbuffer != null ) {
  92             p0 +=offset;
  93             read = ( int ) p0;
  94             if( read < offset || read > bigbuffer.length )
  95                 throw new IllegalArgumentException();
  96         }
  97     }
  98
  99         // XInputStream. This is the basic interface to read data from a stream.
 100
 101     /**
 102      *   States how many bytes can be read or skipped without blocking.
 103      *
 104      *@return  int  If not available, then returned 0
 105      */
 106     public synchronized int available()
 107         throws NotConnectedException, com.sun.star.io.IOException,
 108             com.sun.star.uno.RuntimeException {
 109         if( bigbuffer != null )
 110             return ( bigbuffer.length - read );
 111         else
 112             return 0;
 113     }
 114
 115     /**
 116      *   Closes the stream. .
 117      */
 118     public void closeInput()
 119         throws NotConnectedException,com.sun.star.io.IOException,
 120         com.sun.star.uno.RuntimeException {
 121         read = -1;
 122     }
 123
 124     /**
 125      *   Reads the specified number of bytes in the given sequence.
 126      */
 127     public synchronized int readBytes(byte[][] p0, int p1)
 128         throws NotConnectedException, BufferSizeExceededException,
 129             com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
 130         if( bigbuffer != null ) {
 131             if( read == -1 )
 132                   return 0;
 133             int i = 0;
 134             int available;
 135             if ( p1 > bigbuffer.length - read )
 136                 available = bigbuffer.length - read;
 137             else
 138                 available = p1;
 139
 140             p0[0] = new byte[p1];
 141             while( available != 0 ) {
 142                 p0[0][i++] = bigbuffer[read++];
 143                 --available;
 144             }
 145             return i;
 146         } else {
 147             p0[0] = new byte[0];
 148             return 0;
 149         }
 150     }
 151
 152     /**
 153      *  Reads the available number of bytes at maximum  nMaxBytesToRead .
 154      *  This method blocks the thread until at least one byte is available.
 155      */
 156     public synchronized int readSomeBytes(byte[][] p0, int p1)
 157             throws  NotConnectedException,
 158                     BufferSizeExceededException,
 159                     com.sun.star.io.IOException,
 160                     com.sun.star.uno.RuntimeException {
 161             return readBytes( p0,p1 );
 162     }
 163
 164     /**
 165      *  Skips the next nBytesToSkip bytes (must be positive).
 166      *  It is up to the implementation whether this method is blocking the thread or not.
 167      */
 168     public synchronized void skipBytes(int p0)
 169         throws  NotConnectedException, BufferSizeExceededException,
 170             com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
 171         read += p0;
 172         if( read > bigbuffer.length )
 173             read = bigbuffer.length;
 174
 175         if( read < offset )
 176             read = offset;
 177     }
 178 }
 179
 180 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */