com.scudata.parallel.RemoteCursorProxy Maven / Gradle / Ivy

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SPL(Structured Process Language) A programming language specially for structured data computing.

There is a newer version: 20240823

package com.scudata.parallel;

import com.scudata.common.*;
import com.scudata.dm.*;
import com.scudata.dm.cursor.ICursor;
import com.scudata.server.unit.UnitServer;

/**
 * Զ???α????
 * ??ֹʹ?û???һ??????ȡ???ݽṹ?????α??¼Ϊ??ʱ??????row???????һ?к󣬻??Զ?close?????α?
 * Ȼ????ɺ????α???????????α걻???ˣ???û?ˣ?
 * @author Joancy
 *
 */
public class RemoteCursorProxy extends ICursor {
	RemoteCursorProxyManager rcpm;
	ICursor cs;
	int proxyId = -1;
	
	private long lastAccessTime = -1;
	
	/**
	 * ????Զ???α????
	 * @param cs ?α?
	 */
	public RemoteCursorProxy(ICursor cs) {
		this(null,cs,-1);
	}
	
	/**
	 * ????Զ???α????
	 * @param rcpm Զ???α??????????
	 * @param cs ?α????
	 * @param id ???????
	 */
	public RemoteCursorProxy(RemoteCursorProxyManager rcpm, ICursor cs, int id) {
		if(rcpm==null){
			this.rcpm = RemoteCursorProxyManager.getInstance();
			this.proxyId = UnitServer.nextId();
			this.rcpm.addProxy(this);
		}else{
			this.rcpm = rcpm;
			this.proxyId = id;
		}
		this.cs = cs;
		access();
	}

	ICursor getCursor() {
		return cs;
	} 

	int getProxyID() {
		return proxyId;
	}

	protected long skipOver(long n) {
		return cs.skip(n);
	}

	/**
	 * ???ٵ?ǰ????
	 */
	public void destroy() {
		cs.close();
	}

	/**
	 * ?ر?ʱ????ǰ???????????еĴ????б???ɾ??
	 */
	public synchronized void close() {
		destroy();
		rcpm.delProxy(proxyId);
	}

	protected Sequence get(int n) {
		Sequence tmp = cs.fetch(n);
		access();
		return tmp;
	}

	/**
	 * ʵ??toString?ı?????
	 */
	public String toString() {
		return "RemoteCursorProxy :" + proxyId;
	}
	
	/**
	 * ȡ???ݽṹ
	 */
	public DataStruct getDataStruct() {
		if(dataStruct!=null) return dataStruct;
		dataStruct = cs.getDataStruct();
			
		return dataStruct;
	}
	
	void access() {
		lastAccessTime = System.currentTimeMillis();
	}

	/**
	 * ??ʱ???
	 * @param timeOut ??ʱ??ʱ??
	 * @return ?????ʱ?????ٶ??󣬷???true?????򷵻?false
	 */
	public boolean checkTimeOut(int timeOut) {
		// ??????룬timeOut??λΪ??
		if ((System.currentTimeMillis() - lastAccessTime) / 1000 > timeOut) {
			Logger.info(this + " is timeout.");
			destroy();
			return true;
		}
		return false;
	}
}