attachment.java

来自「一个MMORPG手机游戏的服务器端程序源代码」· Java 代码 · 共 87 行

package zsw_mmorpg.common;
import java.nio.ByteBuffer;
import java.nio.BufferUnderflowException;
import java.nio.ByteOrder;

import org.apache.log4j.Logger;
/**
 * Attachment.java
 *
 * 缓存
 *
 * @author <a href="mailto:[e-mail]">朱世伟</a>
 * @version 1.0
 */

/**缓存*/
public class Attachment {

    public static final int HEADER_SIZE = 12;

    private static Logger log = Logger.getLogger("Attachment");

    int clientId;

    int payloadSize;

    public int gameNameHash;

    private boolean gotHeader;

    public ByteBuffer readBuff;

     public byte payload[];
    public Attachment (){
	payload = new byte[Globals.MAX_EVENT_SIZE];
	readBuff = ByteBuffer.allocate(Globals.NET_BUFFER_SIZE);
    readBuff.order(ByteOrder.LITTLE_ENDIAN);
    }

    public boolean eventReady() throws IllegalArgumentException {
	if (checkHeader() && checkPayload())
	    return true;
	else
	    return false;
    }

    public void reset() {
	gotHeader = false;
    }

    private boolean checkHeader() throws IllegalArgumentException {
	if (gotHeader) return true;
	if (readBuff.remaining() >= HEADER_SIZE) {
	    // read the header info
//	    clientId = readBuff.getInt();     //没用
//	    gameNameHash = readBuff.getInt();//没用
	    payloadSize = readBuff.getInt();

	    // check bounds on the payload
	    if (payloadSize > Globals.MAX_EVENT_SIZE) 
		throw new IllegalArgumentException("Header specifies payload size (" + 
						   payloadSize + ") greater than MAX_EVENT_SIZE(" + 
						   Globals.MAX_EVENT_SIZE + ")");
	    gotHeader = true;
	    return true;
	}
	else {
	    return false;
	}
    }

    private boolean checkPayload() {
	if (readBuff.remaining() >= payloadSize) {
 	    try {
  		readBuff.get(payload, 0, payloadSize);
 	    }
 	    catch (BufferUnderflowException bue) {
 		log.error("buffer underflow", bue);
 	    }
	    return true;
	}
	else {
	    return false;
	}
    }
}// Attachment