watermark.java

来自「与postgresql数据库结合的数据库水印软件包」· Java 代码 · 共 54 行

/*
 * 
 * Copyright 2003,2004 The Watermill Team
 *
 * This file is part of Watermill.
 *
 *    Watermill is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    Watermill is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with Watermill; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
package Watermill.kernel;

import java.util.*;
import java.io.*;

public class Watermark extends HashMap implements Serializable {
    public double correlate(Document original,Document suspect){
	int size=keySet().size();
	int match=0;

	for(Iterator i=keySet().iterator();i.hasNext();){
	    Identifier id=(Identifier)i.next();
	    int originalValue=original.getValue(id).get();
	    Msg.debug("original "+originalValue);
	    
	    Value s=(Value)suspect.getValue(id);
	    if (s!=null){
		int suspectValue=s.get();
		Msg.debug("suspect "+suspectValue);
		int mark=((Value)get(id)).get();
		Msg.debug("mark "+mark);
		if (originalValue+mark==suspectValue)
		    match++;
	    }
	    else {
		Msg.debug("An element is missing");
	    }
	}

	return (double)match/(double)size;
    }
}