rowdatapacket.java

mysql集群

/*
 * 	This program is free software; you can redistribute it and/or modify it under the terms of 
 * the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, 
 * or (at your option) any later version. 
 * 
 * 	This program is distributed in the hope that it will be useful, 
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 * See the GNU General Public License for more details. 
 * 	You should have received a copy of the GNU General Public License along with this program; 
 * if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package com.meidusa.amoeba.mysql.net.packet;

import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import com.meidusa.amoeba.context.ProxyRuntimeContext;
import com.meidusa.amoeba.net.packet.AbstractPacketBuffer;

/**
 * 
 * @author <a href=mailto:[e-mail]>Struct chen</a>
 *
 */
public class RowDataPacket extends AbstractPacket {
	public List<Object> columns;
	private boolean isBinaryEncoded;
	public RowDataPacket(boolean isBinaryEncoded){
		this.isBinaryEncoded = isBinaryEncoded;
	}
	@Override
	public void init(AbstractPacketBuffer myBuffer){
		super.init(myBuffer);
		MysqlPacketBuffer buffer = (MysqlPacketBuffer)myBuffer;
		if(columns == null){
			columns = new ArrayList<Object>();
		}
		
		while(buffer.getPosition()<this.packetLength + HEADER_SIZE){
			columns.add(buffer.readLengthCodedString(ProxyRuntimeContext.getInstance().getServerCharset()));
		}
		
	}
	
	@Override
	public void write2Buffer(AbstractPacketBuffer myBuffer) throws UnsupportedEncodingException{
		super.write2Buffer(myBuffer);
		MysqlPacketBuffer buffer = (MysqlPacketBuffer)myBuffer;
		
		if(!isBinaryEncoded){
			
			if(columns == null)return;
			Iterator<Object> it = columns.iterator();
			while(it.hasNext()){
				Object obj = it.next();
				buffer.writeLengthCodedString(obj != null?obj.toString():null, ProxyRuntimeContext.getInstance().getServerCharset());
			}
		}else{
			myBuffer.writeByte((byte)0);
			if(columns == null)return;
			int numFields = columns.size();
			/* Reserve place for null-marker bytes */
	        int nullCount = (numFields + 9) / 8;
	        byte[] nullBitMask = new byte[nullCount];
	        
	        int nullPosition = buffer.getPosition();
	        buffer.writeBytes(nullBitMask);
	        
	        int nullMaskPos = 0;
	        int bit = 4;
	        int i=0;
	        for(Object colum: columns){
	        	if(colum == null){
	        		nullBitMask[nullMaskPos] |= bit;
	        	}else{
	        		if(colum instanceof BindValue){
	        			BindValue value = (BindValue)colum;
	        			if(!((BindValue)colum).isNull){
	        				PacketUtil.storeBinding(buffer, value, value.charset);
	        			}else{
	        				nullBitMask[nullMaskPos] |= bit;
	        			}
	        		}else{
	        			
	        		}
	        	}
	        	if (((bit <<= 1) & 255) == 0) {
	        		bit = 1; /* To next byte */
	        		nullMaskPos++;
	        	}
	        	i++;
	        }
	       
	        int position = buffer.getPosition();
	        buffer.setPosition(nullPosition);
	        buffer.writeBytes(nullBitMask);
	        buffer.setPosition(position);
		}
	}
	
	
}