org.apache.wicket.util.diff.Diff Maven / Gradle / Ivy
/*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2003 The Apache Software Foundation.
* 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 acknowledgement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Software Foundation.
*
* 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 THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
*
* Within this library, the word text means a unit of information subject to version control.
*
*
* Text is represented as Object[] because the diff engine is capable of handling more
* than plain ascci. In fact, arrays of any type that implements {@link java.lang.Object#hashCode
* hashCode()} and {@link java.lang.Object#equals equals()} correctly can be subject to differencing
* using this library.
*
*
*
* This library provides a framework in which different differencing algorithms may be used. If no
* algorithm is specified, a default algorithm is used.
*
*
* @version $Revision: 1.1 $ $Date: 2006/03/12 00:24:21 $
* @author Juanco Anez
* @see Delta
* @see DiffAlgorithm modifications:
*
* 27 Apr 2003 bwm
*
* Added some comments whilst trying to figure out the algorithm
*
* 03 May 2003 bwm
*
* Factored out the algorithm implementation into a separate difference algorithm class to
* allow pluggable algorithms.
*/
public class Diff extends ToString
{
/** The standard line separator. */
public static final String NL = System.getProperty("line.separator");
/** The line separator to use in RCS format output. */
public static final String RCS_EOL = "\n";
/** The original sequence. */
protected final Object[] orig;
/** The differencing algorithm to use. */
protected DiffAlgorithm algorithm;
/**
* Create a differencing object using the default algorithm
*
* @param original
* the original text that will be compared
*/
public Diff(final Object[] original)
{
this(original, null);
}
/**
* Create a differencing object using the given algorithm
*
* @param original
* the original text that will be compared
* @param algorithm
* the difference algorithm to use.
*/
public Diff(final Object[] original, final DiffAlgorithm algorithm)
{
if (original == null)
{
throw new IllegalArgumentException();
}
orig = original;
if (algorithm != null)
{
this.algorithm = algorithm;
}
else
{
this.algorithm = defaultAlgorithm();
}
}
protected DiffAlgorithm defaultAlgorithm()
{
return new MyersDiff();
}
/**
* compute the difference between an original and a revision.
*
* @param orig
* the original
* @param rev
* the revision to compare with the original.
* @return a Revision describing the differences
* @throws DifferentiationFailedException
*/
public static Revision diff(final Object[] orig, final Object[] rev)
throws DifferentiationFailedException
{
if ((orig == null) || (rev == null))
{
throw new IllegalArgumentException();
}
return diff(orig, rev, null);
}
/**
* compute the difference between an original and a revision.
*
* @param orig
* the original
* @param rev
* the revision to compare with the original.
* @param algorithm
* the difference algorithm to use
* @return a Revision describing the differences
* @throws DifferentiationFailedException
*/
public static Revision diff(final Object[] orig, final Object[] rev,
final DiffAlgorithm algorithm) throws DifferentiationFailedException
{
if ((orig == null) || (rev == null))
{
throw new IllegalArgumentException();
}
return new Diff(orig, algorithm).diff(rev);
}
/**
* compute the difference between the original and a revision.
*
* @param rev
* the revision to compare with the original.
* @return a Revision describing the differences
* @throws DifferentiationFailedException
*/
public Revision diff(final Object[] rev) throws DifferentiationFailedException
{
if ((orig.length == 0) && (rev.length == 0))
{
return new Revision();
}
else
{
return algorithm.diff(orig, rev);
}
}
/**
* Compares the two input sequences.
*
* @param orig
* The original sequence.
* @param rev
* The revised sequence.
* @return true if the sequences are identical. False otherwise.
*/
public static boolean compare(final Object[] orig, final Object[] rev)
{
if (orig.length != rev.length)
{
return false;
}
else
{
for (int i = 0; i < orig.length; i++)
{
if (!orig[i].equals(rev[i]))
{
return false;
}
}
return true;
}
}
/**
* Converts an array of {@link Object Object} to a string using {@link Diff#NL Diff.NL} as the
* line separator.
*
* @param o
* the array of objects.
* @return String
*/
public static String arrayToString(final Object[] o)
{
return arrayToString(o, Diff.NL);
}
/**
* Edits all of the items in the input sequence.
*
* @param text
* The input sequence.
* @return A sequence of the same length with all the lines differing from the corresponding
* ones in the input.
*/
public static Object[] editAll(final Object[] text)
{
Object[] result = new String[text.length];
for (int i = 0; i < text.length; i++)
{
result[i] = text[i] + " ";
}
return result;
}
/**
* Performs random edits on the input sequence. Useful for testing.
*
* @param text
* The input sequence.
* @return The sequence with random edits performed.
*/
public static Object[] randomEdit(final Object[] text)
{
return randomEdit(text, text.length);
}
/**
* Performs random edits on the input sequence. Useful for testing.
*
* @param text
* The input sequence.
* @param seed
* A seed value for the randomizer.
* @return The sequence with random edits performed.
*/
public static Object[] randomEdit(final Object[] text, final long seed)
{
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