344 lines
No EOL
11 KiB
Java
344 lines
No EOL
11 KiB
Java
/*
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* ====================================================================
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*
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* The Apache Software License, Version 1.1
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*
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* Copyright (c) 1999-2003 The Apache Software Foundation.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. The end-user documentation included with the redistribution, if
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* any, must include the following acknowlegement:
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* "This product includes software developed by the
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* Apache Software Foundation (http://www.apache.org/)."
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* Alternately, this acknowlegement may appear in the software itself,
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* if and wherever such third-party acknowlegements normally appear.
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*
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* 4. The names "The Jakarta Project", "Commons", and "Apache Software
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* Foundation" must not be used to endorse or promote products derived
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* from this software without prior written permission. For written
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* permission, please contact apache@apache.org.
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*
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* 5. Products derived from this software may not be called "Apache"
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* nor may "Apache" appear in their names without prior written
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* permission of the Apache Group.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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* ====================================================================
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*
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* This software consists of voluntary contributions made by many
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* individuals on behalf of the Apache Software Foundation. For more
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* information on the Apache Software Foundation, please see
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* <http://www.apache.org/>.
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*
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*/
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package org.apache.commons.jrcs.diff;
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import java.util.*;
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import org.apache.commons.jrcs.diff.myers.MyersDiff;
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import org.apache.commons.jrcs.util.ToString;
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/**
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* Implements a differencing engine that works on arrays of {@link Object Object}.
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*
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* <p>Within this library, the word <i>text</i> means a unit of information
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* subject to version control.
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*
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* <p>Text is represented as <code>Object[]</code> because
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* the diff engine is capable of handling more than plain ascci. In fact,
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* arrays of any type that implements
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* {@link java.lang.Object#hashCode hashCode()} and
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* {@link java.lang.Object#equals equals()}
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* correctly can be subject to differencing using this
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* library.</p>
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*
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* <p>This library provides a framework in which different differencing
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* algorithms may be used. If no algorithm is specififed, a default
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* algorithm is used.</p>
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*
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* @version $Revision: 1.1 $ $Date: 2003/07/14 12:22:29 $
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* @author <a href="mailto:juanco@suigeneris.org">Juanco Anez</a>
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* @see Delta
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* @see DiffAlgorithm
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*
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* modifications:
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*
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* 27 Apr 2003 bwm
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*
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* Added some comments whilst trying to figure out the algorithm
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*
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* 03 May 2003 bwm
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*
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* Factored out the algorithm implementation into a separate difference
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* algorithm class to allow pluggable algorithms.
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*/
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public class Diff
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extends ToString
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{
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/** The standard line separator. */
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public static final String NL = System.getProperty("line.separator");
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/** The line separator to use in RCS format output. */
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public static final String RCS_EOL = "\n";
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/** The original sequence. */
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protected final Object[] orig;
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/** The differencing algorithm to use. */
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protected DiffAlgorithm algorithm;
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/**
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* Create a differencing object using the default algorithm
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*
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* @param the original text that will be compared
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*/
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public Diff(Object[] original)
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{
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this(original, null);
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}
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/**
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* Create a differencing object using the given algorithm
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*
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* @param o the original text which will be compared against
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* @param algorithm the difference algorithm to use.
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*/
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public Diff(Object[] original, DiffAlgorithm algorithm)
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{
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if (original == null)
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{
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throw new IllegalArgumentException();
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}
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this.orig = original;
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if (algorithm != null)
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this.algorithm = algorithm;
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else
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this.algorithm = defaultAlgorithm();
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}
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protected DiffAlgorithm defaultAlgorithm()
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{
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return new MyersDiff();
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}
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/**
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* compute the difference between an original and a revision.
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*
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* @param orig the original
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* @param rev the revision to compare with the original.
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* @return a Revision describing the differences
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*/
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public static Revision diff(Object[] orig, Object[] rev)
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throws DifferentiationFailedException
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{
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if (orig == null || rev == null)
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{
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throw new IllegalArgumentException();
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}
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return diff(orig, rev, null);
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}
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/**
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* compute the difference between an original and a revision.
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*
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* @param orig the original
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* @param rev the revision to compare with the original.
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* @param algorithm the difference algorithm to use
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* @return a Revision describing the differences
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*/
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public static Revision diff(Object[] orig, Object[] rev,
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DiffAlgorithm algorithm)
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throws DifferentiationFailedException
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{
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if (orig == null || rev == null)
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{
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throw new IllegalArgumentException();
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}
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return new Diff(orig, algorithm).diff(rev);
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}
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/**
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* compute the difference between the original and a revision.
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*
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* @param rev the revision to compare with the original.
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* @return a Revision describing the differences
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*/
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public Revision diff(Object[] rev)
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throws DifferentiationFailedException
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{
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return algorithm.diff(orig, rev);
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}
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/**
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* Compares the two input sequences.
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* @param orig The original sequence.
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* @param rev The revised sequence.
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* @return true if the sequences are identical. False otherwise.
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*/
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public static boolean compare(Object[] orig, Object[] rev)
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{
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if (orig.length != rev.length)
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{
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return false;
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}
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else
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{
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for (int i = 0; i < orig.length; i++)
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{
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if (!orig[i].equals(rev[i]))
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{
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return false;
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}
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}
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return true;
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}
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}
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/**
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* Converts an array of {@link Object Object} to a string
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* using {@link Diff#NL Diff.NL}
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* as the line separator.
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* @param o the array of objects.
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*/
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public static String arrayToString(Object[] o)
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{
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return arrayToString(o, Diff.NL);
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}
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/**
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* Edits all of the items in the input sequence.
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* @param text The input sequence.
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* @return A sequence of the same length with all the lines
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* differing from the corresponding ones in the input.
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*/
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public static Object[] editAll(Object[] text)
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{
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Object[] result = new String[text.length];
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for(int i = 0; i < text.length; i++)
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result[i] = text[i] + " <edited>";
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return result;
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}
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/**
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* Performs random edits on the input sequence. Useful for testing.
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* @param text The input sequence.
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* @return The sequence with random edits performed.
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*/
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public static Object[] randomEdit(Object[] text)
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{
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return randomEdit(text, text.length);
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}
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/**
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* Performs random edits on the input sequence. Useful for testing.
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* @param text The input sequence.
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* @param seed A seed value for the randomizer.
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* @return The sequence with random edits performed.
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*/
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public static Object[] randomEdit(Object[] text, long seed)
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{
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List result = new ArrayList(Arrays.asList(text));
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Random r = new Random(seed);
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int nops = r.nextInt(10);
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for (int i = 0; i < nops; i++)
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{
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boolean del = r.nextBoolean();
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int pos = r.nextInt(result.size() + 1);
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int len = Math.min(result.size() - pos, 1 + r.nextInt(4));
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if (del && result.size() > 0)
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{ // delete
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result.subList(pos, pos + len).clear();
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}
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else
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{
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for (int k = 0; k < len; k++, pos++)
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{
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result.add(pos,
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"[" + i + "] random edit[" + i + "][" + i + "]");
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}
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}
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}
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return result.toArray();
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}
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/**
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* Shuffles around the items in the input sequence.
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* @param text The input sequence.
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* @return The shuffled sequence.
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*/
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public static Object[] shuffle(Object[] text)
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{
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return shuffle(text, text.length);
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}
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/**
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* Shuffles around the items in the input sequence.
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* @param text The input sequence.
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* @param seed A seed value for randomizing the suffle.
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* @return The shuffled sequence.
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*/
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public static Object[] shuffle(Object[] text, long seed)
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{
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List result = new ArrayList(Arrays.asList(text));
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Collections.shuffle(result);
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return result.toArray();
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}
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/**
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* Generate a random sequence of the given size.
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* @param The size of the sequence to generate.
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* @return The generated sequence.
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*/
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public static Object[] randomSequence(int size)
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{
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return randomSequence(size, size);
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}
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/**
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* Generate a random sequence of the given size.
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* @param The size of the sequence to generate.
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* @param seed A seed value for randomizing the generation.
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* @return The generated sequence.
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*/
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public static Object[] randomSequence(int size, long seed)
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{
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Integer[] result = new Integer[size];
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Random r = new Random(seed);
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for(int i = 0; i < result.length; i++)
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{
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result[i] = new Integer(r.nextInt(size));
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}
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return result;
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}
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} |