Patch.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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package difflib;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;

/**
 * Describes the patch holding all deltas between the original and revised texts.
 * 
 * @author <a href="dm.naumenko@gmail.com">Dmitry Naumenko</a>
 * @param <T> The type of the compared elements in the 'lines'.
 */
public class Patch<T> {
    private List<Delta<T>> deltas = new LinkedList<Delta<T>>();

    /**
     * Apply this patch to the given target
     * @return the patched text
     * @throws PatchFailedException if can't apply patch
     */
    public List<T> applyTo(List<T> target) throws PatchFailedException {
        List<T> result = new LinkedList<T>(target);
        ListIterator<Delta<T>> it = getDeltas().listIterator(deltas.size());
        while (it.hasPrevious()) {
            Delta<T> delta = (Delta<T>) it.previous();
            delta.applyTo(result);
        }
        return result;
    }
    
    /**
     * Restore the text to original. Opposite to applyTo() method.
     * @param target the given target
     * @return the restored text
     */
    public List<T> restore(List<T> target) {
        List<T> result = new LinkedList<T>(target);
        ListIterator<Delta<T>> it = getDeltas().listIterator(deltas.size());
        while (it.hasPrevious()) {
            Delta<T> delta = (Delta<T>) it.previous();
            delta.restore(result);
        }
        return result;
    }
    
    /**
     * Add the given delta to this patch
     * @param delta the given delta
     */
    public void addDelta(Delta<T> delta) {
        deltas.add(delta);
    }

    /**
     * Get the list of computed deltas
     * @return the deltas
     */
    public List<Delta<T>> getDeltas() {
        Collections.sort(deltas, DeltaComparator.INSTANCE);
        return deltas;
    }
}