cbint.java

实现数据库的storage manager 功能

/*
 * Copyright (c) 2000-2004, Rickard C鰏ter, Martin Svensson
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * 
 * Redistributions of source code must retain the above copyright notice, 
 * this list of conditions and the following disclaimer. 
 * Redistributions 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 SICS nor the names of its contributors 
 * may be used to endorse or promote products derived from this software 
 * without specific prior written permission. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 *
 *
 */

package com.mellowtech.disc;

import com.mellowtech.disc.*;
import java.nio.*;

/**
 * Wraps an int value as a ByteStorable
 *
 * @author Martin Svensson
 * @version 1.0
 */
public class CBInt extends ByteStorable{
  
  /**
   * Value of this CBInt
   *
   */
  protected int value;

  /**
   * Default constructor is needed to create a new inte from
   * a byte buffer.
   *
   */
  public CBInt(){
    ;
  }
  
  /**
   * Initaalize with an int value
   *
   * @param value the value
   */
  public CBInt(int value){
    this.value = value;
  }

  
  //***********GET/SET**************
  /**
   * Set the int value
   *
   * @param value an <code>int</code> value
   */
  public void setValue(int value){
    this.value = value;
  }

  /**
   * Get the value of this CBInt
   *
   * @return an <code>int</code> value
   */
  public int getValue(){
    return value;
  }

  //***********OVERWRITTEN BYTESTORABLE****************
  public int byteSize(){
    return 4;
  }

  public int byteSize(ByteBuffer bb){
    return 4;
  }
  
  public int byteSize(byte[] b, int offset){
    return 4;
  }

  public void toBytes(ByteBuffer bb){
    bb.putInt(value);
  }

  public int toBytes(byte b[], int offset){
    ByteBuffer bb = ByteBuffer.wrap(b);
    bb.position(offset);
    toBytes(bb);
    //ByteStorage.writeInt(b, offset, value);
    return 4;
  }
  
  public ByteStorable fromBytes(ByteBuffer bb){
    return new CBInt(bb.getInt());
  }
    
  public ByteStorable fromBytes(byte b[], int offset){
    ByteBuffer bb = ByteBuffer.wrap(b);
    bb.position(offset);
    return fromBytes(bb);
    //CBInt tmp = new CBInt(ByteStorage.readInt(b, offset));
    //return tmp;
  }

  public int compareTo(Object other){
    CBInt o = (CBInt) other;
    return this.value - o.value;
  }

  public String toString(){
    return ""+value;
  }
  
}