SiteManagerWatcherDaemon.java

package guang.crawler.siteManager.daemon;

import guang.crawler.centerConfig.CenterConfig;
import guang.crawler.centerConfig.siteManagers.SiteManagerInfo;
import guang.crawler.centerConfig.sitesConfig.SitesConfigInfo;
import guang.crawler.siteManager.SiteConfig;
import guang.crawler.siteManager.SiteManager;

import java.io.IOException;
import java.util.Date;

import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;

/**
 * 监控中央配置中自己节点的信息，并根据这些信息决定自己的工作。
 *
 * @author sun
 *
 */
public class SiteManagerWatcherDaemon implements Watcher, Runnable {
	/**
	 * 事件发生的时间
	 */
	private Date	eventTime	= new Date();

	public SiteManagerWatcherDaemon() {
		// TODO Auto-generated constructor stub
	}

	/**
	 * 处理事件
	 */
	@Override
	public void process(final WatchedEvent event) {
		// 首先，立即注册一个事件监听
		SiteManagerInfo siteManagerInfo = SiteConfig.me()
		                                            .getSiteManagerInfo();
		try {
			siteManagerInfo.watchNode(this);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		if (event.getType() == Watcher.Event.EventType.NodeDataChanged) {
			// 如果节点信息更改了
			try {
				siteManagerInfo.load();
				synchronized (this.eventTime) {
					this.eventTime.setTime(System.currentTimeMillis());
					this.eventTime.notifyAll();
				}
			} catch (InterruptedException e) {
				return;
			} catch (IOException e) {
				return;
			}

		}
	}

	@Override
	public void run() {
		// 首先，立即注册一个事件监听
		SiteConfig siteConfig = SiteConfig.me();
		SiteManagerInfo siteManagerInfo = siteConfig.getSiteManagerInfo();
		try {
			siteManagerInfo.watchNode(this);
		} catch (Exception e) {
			e.printStackTrace();
			return;
		}

		SitesConfigInfo sitesConfigInfo;
		try {
			sitesConfigInfo = CenterConfig.me()
			                              .getSitesConfigInfo();
		} catch (Exception e) {
			e.printStackTrace();
			return;
		}

		while (true) {
			Date now = new Date();
			try {
				siteManagerInfo.load();
			} catch (Exception e) {
				e.printStackTrace();
				return;
			}
			boolean dispatched = siteManagerInfo.isDispatched();
			String siteToHandle = siteManagerInfo.getSiteToHandle();
			// 判断是否需要停止
			if (siteConfig.isDispatched()
			        && ((!dispatched) || (!siteToHandle.equals(siteConfig.getSiteToHandle()
			                                                             .getSiteId())))) {
				// 这种情况需要关闭当前已经运行的站点管理器
				SiteManager.me()
				           .stopGathering();
				siteConfig.setDispatched(false);
				try {
					CenterConfig.me()
					            .getWorkersInfo()
					            .getOnlineWorkers()
					            .notifyChanged();
				} catch (Exception e) {
					e.printStackTrace();
					// this should not happen
				}
			}
			// 判断是否需要开启
			if (dispatched && (!siteConfig.isDispatched())) {
				// 如果需要启动，而当前没有启动，那么启动之
				// 然后使用新的配置
				try {
					siteConfig.setSiteToHandle(sitesConfigInfo.getSitesInfo()
					                                          .getSite(siteManagerInfo.getSiteToHandle()));
				} catch (Exception e) {
					e.printStackTrace();
					return;
				}
				// 使用新的配置启动系统
				try {
					SiteManager.me()
					           .startGathering();
				} catch (Exception e) {
					e.printStackTrace();
					return;
				}
				siteConfig.setDispatched(true);
				try {
					CenterConfig.me()
					            .getWorkersInfo()
					            .getOnlineWorkers()
					            .notifyChanged();
				} catch (Exception e) {
					e.printStackTrace();
					// this should not happen

				}
			}

			synchronized (this.eventTime) {
				if (now.after(this.eventTime)) {
					try {
						this.eventTime.wait();
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
						return;
					}
				}
			}
		}

	}
}