Chunk.java

/*
 * SPDX-License-Identifier: Apache-1.1
 *
 * ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2003 The Apache Software Foundation.
 * Copyright (c) 1996-2006 Juancarlo Añez
 * 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.
 *
 * 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 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
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
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 *
 * 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
 * <http://www.apache.org/>.
 */
package difflib;

import java.util.Arrays;
import java.util.List;

import javax.annotation.Nonnegative;

/**
 * Holds the information about the part of text involved in the diff process <p> Text is represented as
 * <code>Object[]</code> because the diff engine is capable of handling more than plain ascci. In fact, arrays or lists
 * 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. </p>
 * @param <T> The type of the compared elements in the 'lines'.
 * @author <a href="dm.naumenko@gmail.com>Dmitry Naumenko</a>
 */
public class Chunk<T> {
    @Nonnegative
    private final int position;
    private List<T> lines;

    /**
     * Creates a chunk and saves a copy of affected lines
     * @param position the start position
     * @param lines    the affected lines
     */
    public Chunk(@Nonnegative int position, List<T> lines) {
        if (position < 0) throw new IllegalArgumentException();
        this.position = position;
        this.lines = lines;
    }

    /**
     * Creates a chunk and saves a copy of affected lines
     * @param position the start position (zero-based numbering)
     * @param lines    the affected lines
     */
    public Chunk(@Nonnegative int position, T[] lines) {
        if (position < 0) throw new IllegalArgumentException();
        this.position = position;
        this.lines = Arrays.asList(lines);
    }

    /**
     * Verifies that this chunk's saved text matches the corresponding text in the given sequence.
     * @param target the sequence to verify against.
     */
    public void verify(List<T> target) throws PatchFailedException {
        if (last() > target.size()) {
            throw new PatchFailedException("Incorrect Chunk: the position of chunk > target size");
        }
        for (int i = 0; i < size(); i++) {
            if (!target.get(position + i).equals(lines.get(i))) {
                throw new PatchFailedException(
                        "Incorrect Chunk: the chunk content doesn't match the target");
            }
        }
    }

    /**
     * @return the start position of chunk in the text (zero-based numbering)
     */
    @Nonnegative
    public int getPosition() {
        return position;
    }

    public void setLines(List<T> lines) {
        this.lines = lines;
    }

    /**
     * @return the affected lines
     */
    public List<T> getLines() {
        return lines;
    }

    @Nonnegative
    public int size() {
        return lines.size();
    }

    /**
     * @return the index of the last line of the chunk. (zero-based numbering)
     */
    @Nonnegative
    public int last() {
        return getPosition() + size() - 1;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((lines == null) ? 0 : lines.hashCode());
        result = prime * result + position;
        result = prime * result + size();
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Chunk<T> other = (Chunk) obj;
        if (lines == null) {
            if (other.lines != null)
                return false;
        } else if (!lines.equals(other.lines))
            return false;
        return position == other.position;
    }

    @Override
    public String toString() {
        return "[position: " + position + ", size: " + size() + ", lines: " + lines + "]";
    }

}