persistent storage-record.java

RMS移动商务应用开发

/* License
 * 
 * Copyright 1994-2004 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  
 *  * Redistribution of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 * 
 *  * Redistribution in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *  
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *  
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility. 
 */

public class Record implements DataInput {

    private RecordStore _rs;
    private byte[] _data;
    private int _length;
    private int _id;
    private DataInputStream _din;

    public Record( RecordStore rs ){
        this( rs, 100 );
    }

    public Record(
              RecordStore rs, int initialRecordSize ){
        _rs     = rs;
        _data   = new byte[ initialRecordSize ];
        _din    = new DataInputStream(
                  new ByteArrayInputStream( _data ) );
        _length = -1;
    }

    public byte[] getByteArray() { return _data; }

    public int getLength() { return _length; }

    public byte[] moveTo( int id )
                 throws RecordStoreNotOpenException,
                              InvalidRecordIDException,
                                  RecordStoreException,
                                           IOException
    {
        _length = _rs.getRecordSize( id );

        if( _length > _data.length ){
            _data = new byte[ _length + 40 ];
            _din  = new DataInputStream(
                   new ByteArrayInputStream( _data ) );
        }

        _rs.getRecord( id, _data, 0 );
        _id = id;
        _din.reset();

        return _data;
    }

    public void readFully(byte b[])
                                  throws IOException {
        _din.readFully( b );
    }

    public void readFully(byte b[], int off, int len)
                                   throws IOException {
        _din.readFully( b, off, len );
    }
       return _din.skipBytes( n );
    }

    public boolean readBoolean() throws IOException {
        return _din.readBoolean();
    }

    public byte readByte() throws IOException {
        return _din.readByte();
    }

    public int readUnsignedByte()
                                   throws IOException {
       return _din.readUnsignedByte();
    }

    public short readShort() throws IOException {
        return _din.readShort();
    }

    public int readUnsignedShort()
                                   throws IOException {
       return _din.readUnsignedShort();
    }

    public char readChar() throws IOException {
        return _din.readChar();
    }
    public int readInt() throws IOException {
        return _din.readInt();
    }

    public long readLong() throws IOException {
        return _din.readLong();
    }

    public String readUTF() throws IOException {
        return _din.readUTF();
    }
}