taskoptimizer.java

利用多线程从搜索引擎下载网页并提取数据到数据库。

import java.util.Date;

public class TaskOptimizer {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

	}

	private int max;
	private int min;
	private long timeout; // time to restart optimizing

	private Date timer; // times sleeping
	private boolean action; // true for optimizing. false for sleeping.
	private boolean taskStarted;  //ensure that no more than the 1st trigger affects its action
	private int optValue;

	public TaskOptimizer(int max, int min, long timeout, int startValue) {
		this.max = max;
		this.min = min;
		this.timeout = timeout;
		this.optValue = startValue;
		//switch2Sleep();
		switch2Action();
	}

	public void taskStart() {
		this.taskStarted = true;
	}

	public void reportTask(boolean result) {
		if (checkAction() || !result)
			optimize(result);

		if (checkAction() && !result) {
			switch2Sleep();
		}
	}

	private void switch2Sleep() {
		action = false;
		timer = new Date();
	}
	private void switch2Action() {
		action = true;
		//timer = new Date();
	}
	private void optimize(boolean result) {
		if (taskStarted) {
			taskStarted = false;
			optValue = result ? optValue + 1 : optValue - 1;
			optValue = (optValue < min) ? min : optValue;
			optValue = (optValue > min) ? max : optValue;
		}
	}

	private boolean checkAction() {
		if (!action) // sleeping check if sleep timeout
			if ((new Date().getTime() - timer.getTime()) > timeout * 1000) {
				action = true;
			}
		return action;
	}

	public int getValue() {
		return optValue;
	}
}