odk/examples/DevelopersGuide/UCB/MyInputStream.java

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  34
  35 import com.sun.star.io.BufferSizeExceededException;
  36 import com.sun.star.io.NotConnectedException;
  37 import com.sun.star.io.XInputStream;
  38 import com.sun.star.io.XSeekable;
  39
  40 /**
  41  * XInputStream interface implementation.
  42  */
  43 public class MyInputStream implements XSeekable, XInputStream {
  44
  45     /**
  46      * Member properties
  47      */
  48     private int offset = 0;
  49     private int read = offset;
  50     private byte[] bigbuffer;
  51
  52     /**
  53      * Constructor
  54      */
  55     public MyInputStream() {
  56     }
  57
  58         // XSeekable. Makes it possible to seek to a certain position within a stream.
  59
  60     /**
  61      *   Returns the length of the stream.
  62      *
  63      *@return  long  The length of the storage medium on which the stream works.
  64      */
  65     public synchronized long getLength()
  66         throws com.sun.star.io.IOException,com.sun.star.uno.RuntimeException {
  67         if ( bigbuffer != null ) {
  68             return bigbuffer.length - offset;
  69         } else {
  70             return 0;
  71         }
  72     }
  73
  74     /**
  75      *   Returns the current offset of the stream.
  76      *
  77      *@return  long  The current offset in this stream.
  78      */
  79     public synchronized long getPosition()
  80         throws com.sun.star.io.IOException,com.sun.star.uno.RuntimeException {
  81         return read - offset ;
  82     }
  83
  84     /**
  85      *  Changes the seek pointer to a new location relative to the beginning of the stream.
  86      */
  87     public synchronized void seek(long p0)
  88         throws IllegalArgumentException, com.sun.star.io.IOException,
  89             com.sun.star.uno.RuntimeException {
  90         if( bigbuffer != null ) {
  91             p0 +=offset;
  92             read = ( int ) p0;
  93             if( read < offset || read > bigbuffer.length )
  94                 throw new IllegalArgumentException();
  95         }
  96     }
  97
  98         // XInputStream. This is the basic interface to read data from a stream.
  99
 100     /**
 101      *   States how many bytes can be read or skipped without blocking.
 102      *
 103      *@return  int  If not available, then returned 0
 104      */
 105     public synchronized int available()
 106         throws NotConnectedException, com.sun.star.io.IOException,
 107             com.sun.star.uno.RuntimeException {
 108         if( bigbuffer != null )
 109             return ( bigbuffer.length - read );
 110         else
 111             return 0;
 112     }
 113
 114     /**
 115      *   Closes the stream. .
 116      */
 117     public void closeInput()
 118         throws NotConnectedException,com.sun.star.io.IOException,
 119         com.sun.star.uno.RuntimeException {
 120         read = -1;
 121     }
 122
 123     /**
 124      *   Reads the specified number of bytes in the given sequence.
 125      */
 126     public synchronized int readBytes(byte[][] p0, int p1)
 127         throws NotConnectedException, BufferSizeExceededException,
 128             com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
 129         if( bigbuffer != null ) {
 130             if( read == -1 )
 131                   return 0;
 132             int i = 0;
 133             int available;
 134             if ( p1 > bigbuffer.length - read )
 135                 available = bigbuffer.length - read;
 136             else
 137                 available = p1;
 138
 139             p0[0] = new byte[p1];
 140             while( available != 0 ) {
 141                 p0[0][i++] = bigbuffer[read++];
 142                 --available;
 143             }
 144             return i;
 145         } else {
 146             p0[0] = new byte[0];
 147             return 0;
 148         }
 149     }
 150
 151     /**
 152      *  Reads the available number of bytes at maximum  nMaxBytesToRead .
 153      *  This method blocks the thread until at least one byte is available.
 154      */
 155     public synchronized int readSomeBytes(byte[][] p0, int p1)
 156             throws  NotConnectedException,
 157                     BufferSizeExceededException,
 158                     com.sun.star.io.IOException,
 159                     com.sun.star.uno.RuntimeException {
 160             return readBytes( p0,p1 );
 161     }
 162
 163     /**
 164      *  Skips the next nBytesToSkip bytes (must be positive).
 165      *  It is up to the implementation whether this method is blocking the thread or not.
 166      */
 167     public synchronized void skipBytes(int p0)
 168         throws  NotConnectedException, BufferSizeExceededException,
 169             com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
 170         read += p0;
 171         if( read > bigbuffer.length )
 172             read = bigbuffer.length;
 173
 174         if( read < offset )
 175             read = offset;
 176     }
 177 }