mysqlmessagehandlerrunner.java

来自「mysql集群」· Java 代码 · 共 204 行

package com.meidusa.amoeba.aladdin.handler;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;

import com.meidusa.amoeba.aladdin.io.MysqlResultSetPacket;
import com.meidusa.amoeba.aladdin.io.ResultPacket;
import com.meidusa.amoeba.mysql.jdbc.MysqlDefs;
import com.meidusa.amoeba.mysql.net.packet.EOFPacket;
import com.meidusa.amoeba.mysql.net.packet.FieldPacket;
import com.meidusa.amoeba.mysql.net.packet.ResultSetHeaderPacket;
import com.meidusa.amoeba.mysql.net.packet.RowDataPacket;
import com.meidusa.amoeba.net.MessageHandler;
import com.meidusa.amoeba.net.packet.AbstractPacketBuffer;
import com.meidusa.amoeba.net.packet.PacketBuffer;
import com.meidusa.amoeba.util.Initialisable;
import com.meidusa.amoeba.util.InitialisationException;
import com.meidusa.amoeba.xmltable.Condition;
import com.meidusa.amoeba.xmltable.XmlColumn;
import com.meidusa.amoeba.xmltable.XmlRow;
import com.meidusa.amoeba.xmltable.XmlTable;
import com.meidusa.amoeba.xmltable.XmlTableLoader;

/**
 * 这个负责mysql 特有的一些 select query 的应答,该类只是简单的将一些特殊sql进行从xmltable 文件中进行定位。
 * 然后反馈给客户端一些数据
 * @author struct
 *
 */
public class MysqlMessageHandlerRunner implements MessageHandlerRunner,Initialisable {
	private ResultPacket packet = null;
	private String query;
	private String xmlTable;
	private static Map<String,XmlTable> xmlTableMap;
	private static Map<String,byte[]> resultContent = new HashMap<String,byte[]>();
	
	public String getXmlTable() {
		return xmlTable;
	}
	public void setXmlTable(String collationFile) {
		this.xmlTable = collationFile;
	}
	public MysqlMessageHandlerRunner(){
		
	}
	public void init(MessageHandler handler) {
		CommandMessageHandler chandler = (CommandMessageHandler)handler;
		this.packet = chandler.packet;
		this.query = chandler.query;
	}

	public void reset() {
		this.packet = null;
		this.query = null;
	}

	public void run() {
		query = query.toLowerCase();
		byte[] content = resultContent.get(query);
		if(content != null){
			MysqlResultSetPacket resultPacket = (MysqlResultSetPacket)packet;
			resultPacket.setContent(content);
			return;
		}
		StringTokenizer tokenizer = new StringTokenizer(query," 	%'");
		String[] tokens = new String[tokenizer.countTokens()]; 
		int index=0;
		
		
		while(tokenizer.hasMoreTokens()){
			tokens[index++]=tokenizer.nextToken();
		}
		if(tokens.length >1){
			boolean isSelect = tokens[0].equalsIgnoreCase("select") || tokens[0].equalsIgnoreCase("show");
			if(isSelect){
				String tableName = tokens[1];
				Condition condition = null;
				for(int i=2;i<tokens.length;i++){
					if(tokens[i].equals("where")){
						condition = new Condition();
						condition.name = tokens[i+1];
						if(tokens[i+2].equals("=")){
							condition.type = Condition.TYPE.match;
						}else if(tokens[i+2].equals("like")){
							condition.type = Condition.TYPE.match;
						}
						condition.value = tokens[i+3];
						break;
					}else if(tokens[i].equals("like")){
						condition = new Condition();
						condition.name = tokens[i+1];
						condition.type = Condition.TYPE.exist;
					}else if(tokens[i].equals("from")){
						tableName = tokens[i+1];
					}
				}
		
				XmlTable xmlTable = xmlTableMap.get(tableName);
				if(xmlTable != null){
					if(tableName.equals("variables") && condition != null){
						if(condition.value == null){
							condition.value = condition.name;
							condition.type = Condition.TYPE.match;
							condition.name = "variable_name";
						}
					}
					synchronized (resultContent) {
						content = resultContent.get(query);
						if(content == null){
							content = xmlTableToBytes(xmlTable.query(condition));
							resultContent.put(query, content);
						}
					}
					MysqlResultSetPacket resultPacket = (MysqlResultSetPacket)packet;
					resultPacket.setContent(content);
					return;
				}
			
				MysqlResultSetPacket resultPacket = (MysqlResultSetPacket)packet;
				ResultSetHeaderPacket resultHeader = new ResultSetHeaderPacket();
				resultHeader.packetId = 1;
				resultHeader.columns =1;
				
				resultPacket.resulthead = resultHeader;
				FieldPacket field = new FieldPacket();
				field.name = "test";
				field.type = (byte)MysqlDefs.FIELD_TYPE_VAR_STRING;
				field.length = 8;
				resultPacket.fieldPackets = new FieldPacket[]{field};
			}

		}else{
			
		}
	}
	
	private byte[] xmlTableToBytes(XmlTable table){
		
		PacketBuffer buffer = new AbstractPacketBuffer(4086);
		byte paketId = 1;
		
		ResultSetHeaderPacket resultHeader = new ResultSetHeaderPacket();
		resultHeader.packetId = paketId++;
		resultHeader.columns = table.getColumns().size();
		buffer.writeBytes(resultHeader.toByteBuffer(null).array());
		
		for(int i=0;i<resultHeader.columns;i++){
			FieldPacket field = new FieldPacket();
			field.name = table.getColumns().get(i);
			field.length = 8;
			field.packetId = paketId++;
			field.type = (byte)MysqlDefs.FIELD_TYPE_VAR_STRING;
			buffer.writeBytes(field.toByteBuffer(null).array());
		}
		
		EOFPacket fieldEof = new EOFPacket();
		fieldEof.serverStatus = 2;
		fieldEof.warningCount = 0;
		fieldEof.packetId = paketId++;
		buffer.writeBytes(fieldEof.toByteBuffer(null).array());
		
		for(XmlRow xmlRow :table.getRows()){
			RowDataPacket row = new RowDataPacket(false);
			row.columns = new ArrayList<Object>();
			for(int i=0;i<resultHeader.columns;i++){
				XmlColumn column = xmlRow.getColumMap().get(table.getColumns().get(i));
				if(column == null){
					row.columns.add(null);
				}else{
					row.columns.add(column.getValue());
				}
			}
			row.packetId =  paketId++;
			buffer.writeBytes(row.toByteBuffer(null).array());
		}
		
		EOFPacket rowEof = new EOFPacket();
		rowEof.serverStatus = 2;
		rowEof.warningCount = 0;
		rowEof.packetId = paketId++;
		buffer.writeBytes(rowEof.toByteBuffer(null).array());
		return buffer.toByteBuffer().array();
	}
	
	public void init() throws InitialisationException {
		if(xmlTableMap == null){
			if(xmlTable != null){
				synchronized (this) {
					if(xmlTableMap != null) return;
					XmlTableLoader loader = new XmlTableLoader();
					loader.setDTD("/com/meidusa/amoeba/xml/table.dtd");
					loader.setDTDSystemID("table.dtd");
					xmlTableMap = loader.loadXmlTable(xmlTable);
				}
			}else{
				xmlTableMap = new HashMap<String,XmlTable>();
			}
		}
	}

}