executepacket.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.Arrays;
import java.util.Map;

import org.apache.log4j.Logger;

import com.meidusa.amoeba.mysql.jdbc.MysqlDefs;
import com.meidusa.amoeba.net.packet.AbstractPacketBuffer;

/**
 * <pre>
 * Bytes                Name
 *  -----                ----
 *  1                    code
 *  4                    statement_id
 *  1                    flags
 *  4                    iteration_count
 *  (param_count+7)/8    null_bit_map
 *  1                    new_parameter_bound_flag 如果为1表示preparedStatment有参数绑定，否则则为0
 *  n*2                  type of parameters (only if new_params_bound = 1)
 *  
 *  code:          always COM_EXECUTE
 *  
 *  statement_id:  statement identifier
 *  
 *  flags:         reserved for future use. In MySQL 4.0, always 0.
 *                 In MySQL 5.0: 
 *                   0: CURSOR_TYPE_NO_CURSOR
 *                   1: CURSOR_TYPE_READ_ONLY
 *                   2: CURSOR_TYPE_FOR_UPDATE
 *                   4: CURSOR_TYPE_SCROLLABLE
 *  
 *  iteration_count: reserved for future use. Currently always 1.
 *  
 *  null_bit_map:  A bitmap indicating parameters that are NULL.
 *                 Bits are counted from LSB, using as many bytes
 *                 as necessary ((param_count+7)/8)
 *                 i.e. if the first parameter (parameter 0) is NULL, then
 *                 the least significant bit in the first byte will be 1.
 *  
 *  new_parameter_bound_flag:   Contains 1 if this is the first time
 *                              that &quot;execute&quot; has been called, or if
 *                              the parameters have been rebound.
 *  
 *  type:          Occurs once for each parameter that is not NULL.
 *                 The highest significant bit of this 16-bit value
 *                 encodes the unsigned property. The other 15 bits
 *                 are reserved for the type (only 8 currently used).
 *                 This block is sent when parameters have been rebound
 *                 or when a prepared statement is executed for the 
 *                 first time.
 * </pre>
 * 
 * @author <a href=mailto:[e-mail]>Struct chen</a>
 * 
 */
public class ExecutePacket extends CommandPacket {
	private static Logger logger = Logger.getLogger(ExecutePacket.class);
	public long statementId;
	public byte flags;
	public long iterationCount;
	public byte newParameterBoundFlag;
	protected transient int parameterCount;
	public BindValue[] values;
	private Map<Integer, Object> longPrameters;

	public ExecutePacket(int parameterCount, Map<Integer, Object> longPrameters) {
		this.parameterCount = parameterCount;
		values = new BindValue[parameterCount];
		this.longPrameters = longPrameters;
	}

	public static long readStatmentID(byte[] buffer) {
		byte[] b = buffer;
		int position = 5;
		return ((long) b[position++] & 0xff)
				| (((long) b[position++] & 0xff) << 8)
				| ((long) (b[position++] & 0xff) << 16)
				| ((long) (b[position++] & 0xff) << 24);
	}

	@Override
	public void init(AbstractPacketBuffer myBuffer) {
		super.init(myBuffer);
		MysqlPacketBuffer buffer = (MysqlPacketBuffer) myBuffer;
		statementId = buffer.readLong();
		flags = buffer.readByte();
		iterationCount = buffer.readLong();
		int nullCount = (this.parameterCount + 7) / 8;
		byte[] nullBitsBuffer = new byte[nullCount];
		for (int i = 0; i < nullCount; i++) {
			nullBitsBuffer[i] = buffer.readByte();
		}
		newParameterBoundFlag = buffer.readByte();

		for (int i = 0; i < this.parameterCount; i++) {
			if (values[i] == null) {
				values[i] = new BindValue();
			}
		}

		if (newParameterBoundFlag == (byte) 1) {
			for (int i = 0; i < this.parameterCount; i++) {
				this.values[i].bufferType = buffer.readInt();
			}
		}

		for (int i = 0; i < this.parameterCount; i++) {
			if (longPrameters != null && longPrameters.get(i) != null) {
				values[i].isLongData = true;
			} else {
				if ((nullBitsBuffer[i / 8] & (1 << (i & 7))) != 0) {
					values[i].isNull = true;
				} else {
					PacketUtil.readBindValue(buffer, values[i]);
				}
			}
		}
	}

	@Override
	public void write2Buffer(AbstractPacketBuffer myBuffer)
			throws UnsupportedEncodingException {
		super.write2Buffer(myBuffer);
		MysqlPacketBuffer buffer = (MysqlPacketBuffer) myBuffer;
		buffer.writeLong(statementId);
		buffer.writeByte(flags);
		buffer.writeLong(iterationCount);
		buffer.writeByte(newParameterBoundFlag);
		int nullCount = (this.parameterCount + 7) / 8;

		int nullBitsPosition = buffer.getPosition();

		for (int i = 0; i < nullCount; i++) {
			buffer.writeByte((byte) 0);
		}
		byte[] nullBitsBuffer = new byte[nullCount];

		if (newParameterBoundFlag == (byte) 1) {
			for (int i = 0; i < this.parameterCount; i++) {
				buffer.writeInt(this.values[i].bufferType);
			}
		}

		for (int i = 0; i < this.parameterCount; i++) {
			if (!this.values[i].isLongData) {
				if (!this.values[i].isNull) {
					PacketUtil.storeBinding(buffer, this.values[i], buffer
							.getConnection().getCharset());
				} else {
					nullBitsBuffer[i / 8] |= (1 << (i & 7));
				}
			}
		}

		int endPosition = buffer.getPosition();
		buffer.setPosition(nullBitsPosition);
		buffer.writeBytesNoNull(nullBitsBuffer);
		buffer.setPosition(endPosition);
	}

	public Object[] getParameters() {
		Object[] result = new Object[values.length];
		int index = 0;
		for (BindValue bindValue : values) {

			if (bindValue.isNull) {
				index++;
			} else {
				switch (bindValue.bufferType) {

				case MysqlDefs.FIELD_TYPE_TINY:
					result[index++] = bindValue.byteBinding;
					break;
				case MysqlDefs.FIELD_TYPE_SHORT:
					result[index++] = bindValue.shortBinding;
					break;
				case MysqlDefs.FIELD_TYPE_LONG:
					result[index++] = bindValue.longBinding;
					break;
				case MysqlDefs.FIELD_TYPE_LONGLONG:
					result[index++] = bindValue.longBinding;
					break;
				case MysqlDefs.FIELD_TYPE_FLOAT:
					result[index++] = bindValue.floatBinding;
					break;
				case MysqlDefs.FIELD_TYPE_DOUBLE:
					result[index++] = bindValue.doubleBinding;
					break;
				case MysqlDefs.FIELD_TYPE_TIME:
					result[index++] = bindValue.value;
					break;
				case MysqlDefs.FIELD_TYPE_DATE:
				case MysqlDefs.FIELD_TYPE_DATETIME:
				case MysqlDefs.FIELD_TYPE_TIMESTAMP:
					result[index++] = bindValue.value;
					break;
				case MysqlDefs.FIELD_TYPE_VAR_STRING:
				case MysqlDefs.FIELD_TYPE_STRING:
				case MysqlDefs.FIELD_TYPE_VARCHAR:
				case MysqlDefs.FIELD_TYPE_DECIMAL:
				case MysqlDefs.FIELD_TYPE_NEW_DECIMAL:
				case MysqlDefs.FIELD_TYPE_TINY_BLOB:
					result[index++] = bindValue.value;
					break;
				case MysqlDefs.FIELD_TYPE_NULL:
					index++;
				default: {
					index++;
					logger.error("error jdbc type:" + bindValue.bufferType);
				}
				}
			}
		}
		return result;
	}

	protected int calculatePacketSize() {
		int packLength = super.calculatePacketSize();
		packLength += 4 + 1 + 4 + 1;
		return packLength;
	}

	public static void main(String[] args) {
		int parameterCount = 12;
		int nullCount = (parameterCount + 7) / 8;
		byte[] nullBitsBuffer = new byte[nullCount];

		for (int i = 0; i < parameterCount; i++) {
			nullBitsBuffer[i / 8] |= (1 << (i & 7));
		}
		System.out.println(Arrays.toString(nullBitsBuffer));
	}
}