robinsonscanner.java

spam source codejasen-0.9jASEN - java Anti Spam ENgine.zip 如标题所示

/*
 * @(#)RobinsonScanner.java	3/11/2004
 *
 * Copyright (c) 2004, 2005  jASEN.org
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in
 *      the documentation and/or other materials provided with the distribution.
 *
 *   3. The names of the authors may not be used to endorse or promote products
 *      derived from this software without specific prior written permission.
 *
 *   4. Any modification or additions to the software must be contributed back
 *      to the project.
 *
 *   5. Any investigation or reverse engineering of source code or binary to
 *      enable emails to bypass the filters, and hence inflict spam and or viruses
 *      onto users who use or do not use jASEN could subject the perpetrator to
 *      criminal and or civil liability.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JASEN.ORG,
 * OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
package org.jasen.plugins;

import java.io.InputStream;
import java.util.Properties;

import javax.mail.internet.MimeMessage;

import org.jasen.core.ProbabilityTestResult;
import org.jasen.core.calculators.ChiSquaredCalculator;
import org.jasen.core.engine.DiskMapStore;
import org.jasen.core.engine.Jasen;
import org.jasen.core.engine.JasenMap;
import org.jasen.error.JasenException;
import org.jasen.interfaces.JasenMapStore;
import org.jasen.interfaces.JasenMessage;
import org.jasen.interfaces.JasenPlugin;
import org.jasen.interfaces.JasenTestResult;
import org.jasen.interfaces.ParserData;
import org.jasen.interfaces.ReceivedHeaderParser;

/**
 * <P>
 * 	This scanner is the core spam detection system used in jASEN.
 * </P>
 * <p>
 * 	It derives from the propositions put forward by Gary Robinson, and earlier from Paul Graham
 * </p>
 * @author Jason Polites
 * @see <a href="http://www.paulgraham.com/spam.html">http://www.paulgraham.com/spam.html</a>
 * @see <a href="http://www.garyrobinson.net/">http://www.garyrobinson.net/</a>
 */
public class RobinsonScanner implements JasenPlugin
{

    private JasenMap map;

    private int minTokens = 5;
    private float defaultProb = 0.5f;
    
    ChiSquaredCalculator calculator;

    /**
     *
     */
    public RobinsonScanner() {
        super ();
    }

    /* (non-Javadoc)
     * @see org.jasen.interfaces.JasenPlugin#init(java.util.Properties)
     */
    public void init(Properties properties) throws JasenException {
        String mapPath = properties.getProperty("map-path");

        InputStream in = this.getClass().getClassLoader().getResourceAsStream(mapPath);

        if(in == null) {
            throw new JasenException("Error locating token map in " + mapPath + ".  Is this path in the classpath?");
        }

        // Load the token map...
        String strMapStoreClass = properties.getProperty("map-store-class");

        JasenMapStore store = null;

        if(strMapStoreClass != null) {
            try
            {
                store = (JasenMapStore)Class.forName(strMapStoreClass).newInstance();
            }
            catch (InstantiationException e)
            {
                throw new JasenException(e);
            }
            catch (IllegalAccessException e)
            {
                throw new JasenException(e);
            }
            catch (ClassNotFoundException e)
            {
                throw new JasenException(e);
            }
        }
        else
        {
            store = new DiskMapStore();
        }

        map = store.load(in);

        String strMinTokens = properties.getProperty("min-tokens");
        String strDefaultProb = properties.getProperty("default-prob");

        if(strMinTokens != null)
            minTokens = Integer.parseInt(strMinTokens);

        if(strDefaultProb != null)
            defaultProb = Float.parseFloat(strDefaultProb);
        
        calculator = new ChiSquaredCalculator();
    }

    /*
     * (non-Javadoc)
     * @see org.jasen.interfaces.JasenPlugin#destroy()
     */
    public void destroy() throws JasenException {}

    /*
     *  (non-Javadoc)
     * @see org.jasen.interfaces.JasenPlugin#test(org.jasen.core.Jasen, javax.mail.internet.MimeMessage, org.jasen.interfaces.JasenMessage, org.jasen.interfaces.ParserData, org.jasen.interfaces.ReceivedHeaderParser)
     */
    public JasenTestResult test(Jasen engine, MimeMessage rawMessage, JasenMessage parsedMessage, ParserData data, ReceivedHeaderParser parser) throws JasenException {
        ProbabilityTestResult result = new ProbabilityTestResult();

        if(data.getMessageTokens() == null || data.getMessageTokens().length <= minTokens) {
            result.setProbability(defaultProb);
        }
        else
        {
            double prob = calculator.confirmHypothesis(data.getMessageTokens(), map);
            result.setProbability((float)prob);
        }
        return result;
    }

}