Java中队列的用法

1. 定义队列

public  static Vector<ReceiveData>  queueain = new Vector<ReceiveData>();

2. 入队操作

package cn.com.superv.emanager.dnsalarm;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import cn.com.superv.emanager.base.bo.Config;
import cn.com.superv.emanager.manager.ConfigManager;

public class ReceiveFromGW extends Thread{

	private static final Log log = LogFactory.getLog(ReceiveFromGW.class);
	private static final int maxreceivelength = 10240;
	private static int remoteport  = 2000; //这个端口从AM_CONFIG读取
	private static int maxreceive = 10000; // 能接收的最大消息数
	private static DatagramSocket socket=null;
	public  static boolean bRun = true;
	private DatagramPacket inputdp = new DatagramPacket(new byte[maxreceivelength], maxreceivelength);

	private ConfigManager configManager;

	public void setConfigManager(ConfigManager configManager) {
		this.configManager = configManager;
	}

	public ReceiveFromGW() {
		super();
	}

	public void startReceiveFromGW(){
		Config config = configManager.getConfig("ALARM_PORT");
		if(config != null){
			remoteport = Integer.parseInt(config.getValue().trim());
		}
		config = configManager.getConifg("ALARM_MAX_RECEIVE");
		if(config != null){
			maxreceive = Integer.parseInt(config.getValue().trim());
		}
		getDatagramSocket();
		if(socket!=null)
			start();
		log.info("ReceiveFromGW7750 Start Port["+remoteport+"]");
	}

	public static DatagramSocket getDatagramSocket()
	{
		try {
			if(socket==null){
				socket= new DatagramSocket(remoteport);//绑定端口号
				socket.setSendBufferSize(socket.getSendBufferSize()*10);
				socket.setReceiveBufferSize(socket.getReceiveBufferSize()*10);
			}
		} 
		catch (SocketException e) {
			e.printStackTrace();
			log.error(e,e.fillInStackTrace());
		}
		return socket;
	}


	public void run() {
		while(bRun){
			try{
				if(ReceiveAlarm.bAdd){
					if(log.isDebugEnabled())
						log.debug("receive gw7750 message port["+remoteport+"]start.............!");
					socket.receive(inputdp);

					int numBytes = inputdp.getLength();
					byte[] readbytes = new byte[numBytes];
					System.arraycopy(inputdp.getData(), 0, readbytes, 0, numBytes);

					ReceiveData receivedata = new ReceiveData(inputdp.getAddress().getHostAddress(),new String(readbytes));

					ReceiveAlarm.addData(receivedata,maxreceive);
					log.info("data from port["+remoteport+"]  ip:"+receivedata.getIpstr() + " data:" + receivedata.getDatastr());
				    if(log.isDebugEnabled()){
				    	log.debug("receive gw7750 message end.............!");
				    }
				}
			} catch (Exception e) {
				e.printStackTrace();
				log.error(e,e.fillInStackTrace());
			}	
		}
	}
}

3. 操作队列

private final static int MAX_PACKET_LENGTH = 4096;
public  static boolean bRun = true;
public static boolean bAdd = true; // 是否继续接收告警
public  static Vector<ReceiveData>  queueain = new Vector<ReceiveData>();
private DatagramSocket socket=null;
private DatagramPacket outputdp;
private DatagramPacket inputdp = new DatagramPacket(new byte[MAX_PACKET_LENGTH], MAX_PACKET_LENGTH);


/**
  * 以队列的方式接收和发送告警
  * @param receivedata 接收到的数据
  */
public void receiveAlarm(ReceiveData receivedata){
	try {
		updateAlarmData(receivedata.getIpstr(),receivedata.getDatastr());
	} catch (Exception e) {
		log.error(e,e.fillInStackTrace());
	}
}


public void startReceiveAlarm(){
	start();
	log.info("ReceiveAlarm Start!");
}
public void run() {
	while(bRun){
		try{
			synchronized (queueain) {
				if(queueain.isEmpty()){
					try {
			log.info("wait ................................................");
						bAdd = true;
						queueain.wait(1000 * 300);
					} catch (Exception e) {
e.printStackTrace();
						log.error(e,e.fillInStackTrace());
					}
				}
			}
			while (!queueain.isEmpty()) {
				try{
					ReceiveData rd  = (ReceiveData)queueain.firstElement();
                                              queueain.removeElementAt(0);
				         log.info("send .......................................... size: "+queueain.size());
					receiveAlarm(rd);
					} catch (Exception e) {
                                              e.printStackTrace();
					log.error(e,e.fillInStackTrace());
				}
			}
		} catch(Exception ex){
			log.error(ex,ex.fillInStackTrace());
		}
	}
}


public static void addData(ReceiveData receivedata, int maxreceive){

	synchronized(queueain){
		if(queueain.size() > maxreceive){
			bAdd = false;
		}
		if(queueain.size() == 0){
			bAdd = true;
		}
		if(bAdd){
			queueain.add(receivedata);
			queueain.notifyAll();
		}
	}
}