ChangeDelta.java

/*
 * SPDX-License-Identifier: Apache-1.1
 *
 * ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2003 The Apache Software Foundation.
 * Copyright (c) 2010 Dmitry Naumenko (dm.naumenko@gmail.com)
 * Copyright (c) 2015-2016 Brenden Kromhout and contributors to java-diff-utils
 * 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.
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 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
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 */
package difflib;

import java.util.List;

/**
 * Describes the change-delta between original and revised texts.
 * @param T The type of the compared elements in the 'lines'.
 * @author <a href="dm.naumenko@gmail.com">Dmitry Naumenko</a>
 */
public class ChangeDelta<T> extends Delta<T> {

    /**
     * Creates a change delta with the two given chunks.
     * @param original The original chunk. Must not be {@code null}.
     * @param revised  The original chunk. Must not be {@code null}.
     */
    public ChangeDelta(Chunk<T> original, Chunk<T> revised) {
        super(original, revised);
    }

    /**
     * {@inheritDoc}
     * @throws PatchFailedException
     */
    @Override
    public void applyTo(List<T> target) throws PatchFailedException {
        verify(target);
        int position = getOriginal().getPosition();
        int size = getOriginal().size();
        for (int i = 0; i < size; i++) {
            target.remove(position);
        }
        int i = 0;
        for (T line : getRevised().getLines()) {
            target.add(position + i, line);
            i++;
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void restore(List<T> target) {
        int position = getRevised().getPosition();
        int size = getRevised().size();
        for (int i = 0; i < size; i++) {
            target.remove(position);
        }
        int i = 0;
        for (T line : getOriginal().getLines()) {
            target.add(position + i, line);
            i++;
        }
    }

    /**
     * {@inheritDoc}
     */
    public void verify(List<T> target) throws PatchFailedException {
        getOriginal().verify(target);
        if (getOriginal().getPosition() > target.size()) {
            throw new PatchFailedException("Incorrect patch for delta: "
                    + "delta original position > target size");
        }
    }

    @Override
    public String toString() {
        return "[ChangeDelta, position: " + getOriginal().getPosition() + ", lines: "
                + getOriginal().getLines() + " to " + getRevised().getLines() + "]";
    }

    @Override
    public TYPE getType() {
        return Delta.TYPE.CHANGE;
    }
}