srdireplicatest.java

jxta_src_2.41b jxta 2.41b 最新版源码 from www.jxta.org

/*
 *  Copyright (c) 2001 Sun Microsystems, Inc.  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 end-user documentation included with the redistribution,
 *  if any, must include the following acknowledgment:
 *  "This product includes software developed by the
 *  Sun Microsystems, Inc. for Project JXTA."
 *  Alternately, this acknowledgment may appear in the software itself,
 *  if and wherever such third-party acknowledgments normally appear.
 *
 *  4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *  not be used to endorse or promote products derived from this
 *  software without prior written permission. For written
 *  permission, please contact Project JXTA at http://www.jxta.org.
 *
 *  5. Products derived from this software may not be called "JXTA",
 *  nor may "JXTA" appear in their name, without prior written
 *  permission of Sun.
 *
 *  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 SUN MICROSYSTEMS OR
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 *  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 *  ====================================================================
 *
 *  This software consists of voluntary contributions made by many
 *  individuals on behalf of Project JXTA.  For more
 *  information on Project JXTA, please see
 *  <http://www.jxta.org/>.
 *
 *  This license is based on the BSD license adopted by the Apache Foundation.
 *
 *  $Id: SrdiReplicaTest.java,v 1.2 2003/04/17 17:43:20 hamada Exp $
 */

package net.jxta.impl.cm;

import java.math.BigInteger;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import net.jxta.impl.util.JxtaHash;

/**
 *  A SrdiGetReplica unit test
 */
public class SrdiReplicaTest extends TestCase  {

    private JxtaHash jxtaHash = new JxtaHash();
    private static final int OFFBY = 30;
    private static final int ITERATIONS = 10;
    private static final int SIZE = 100;
    private static final String TSTSTR = "This is only a Test, nothing else";

    /**
     *Constructor for the SrdiIndexTest object
     *
     * @param  testName  test name
     */
    public SrdiReplicaTest(String testName) {
        super(testName);
    }

    /**
     *  A unit test suite for JUnit
     *
     * @return    The test suite
     */
    public static Test suite() {
        TestSuite suite = new TestSuite(SrdiReplicaTest.class);
        return suite;
    }
    /**
     *  The JUnit setup method
     */
    protected void setUp() {
    }
    
    public void tearDown() {
             System.gc();
    }

    /**
     *  The main program to test CmCache
     *
     *@param  argv           The command line arguments
     *@exception  Exception  Description of Exception
     */
    public static void main( String[] argv ) throws Exception {
        
        junit.textui.TestRunner.run(suite());
        System.err.flush();
        System.out.flush();
    }

   public void testOffBy() {
       for (int i= 0; i < OFFBY; i++) {
           offBy(i);
       }
    }
    
    private void offBy(int size) {
        System.out.println("Test Off By : "+ size);
        System.out.println("---------------");
        
        for (int i=0; i<ITERATIONS; i++ ) {
            int rp1 = getReplica1(TSTSTR+i, SIZE);
            int rp2 = getReplica2(TSTSTR+i, SIZE);
            int rp11 = getReplica1(TSTSTR+i, SIZE+size);
            int rp21 = getReplica2(TSTSTR+i, SIZE+size);
            System.out.print("Get replica 1 actual pos: "+ rp1 + " RPV Off by "+size+" : "+ rp11 +" skew :" + (rp1 - rp11));
            System.out.println(" ----   Get replica 2 actual pos: "+ rp2 + " Off by "+size+" : "+ rp21 +" skew :" + (rp2 - rp21));
        }
    }
    
    /* 2.0 Replica Function */
    private int getReplica1(String expression, int size) {
            jxtaHash.update(expression);
            return jxtaHash.mod(size);
    }

    /* Replica Function  contributed by Shinya*/
    private int getReplica2(String expression, int size) {
        jxtaHash.update(expression);
        BigInteger sizeOfPeerView=java.math.BigInteger.valueOf(size);
        BigInteger digest=jxtaHash.getDigestInteger().abs();
        BigInteger sizeOfHashSpace=BigInteger.ONE.shiftLeft(8*digest.toByteArray().length);
        return (digest.multiply(sizeOfPeerView)).divide(sizeOfHashSpace).intValue();
    }


}