org.xwiki.diff.internal.DefaultPatch Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of xwiki-commons-diff-api Show documentation
XWiki Commons - Diff API
The newest version!
/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.diff.internal;

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

import org.xwiki.diff.Delta;
import org.xwiki.diff.DiffException;
import org.xwiki.diff.Patch;
import org.xwiki.diff.PatchException;

/**
 * Default implementation of {@link Patch}.
 *
 * @param  the type of compared elements
 * @version $Id: e5349b0b42b6475a7e3cad1efe05a1c3047b73b8 $
 */
public class DefaultPatch extends LinkedList> implements Patch
{
    /**
     * Provides an id for serialization.
     */
    private static final long serialVersionUID = 1L;

    /**
     * Default constructor.
     */
    public DefaultPatch()
    {
    }

    /**
     * Convert {@link difflib.Patch} into {@link Patch}.
     *
     * @param patch the {@link difflib.Patch} to convert
     * @throws DiffException error when converting the patch
     */
    public DefaultPatch(difflib.Patch patch) throws DiffException
    {
        for (difflib.Delta delta : patch.getDeltas()) {
            add(toDelta(delta));
        }
    }

    /**
     * Convert {@link difflib.Delta} into {@link Delta}.
     *
     * @param delta the {@link difflib.Delta} to convert
     * @return the {@link Delta}
     * @throws DiffException error when converting the delta
     */
    private Delta toDelta(difflib.Delta delta) throws DiffException
    {
        Delta newDelta;

        switch (delta.getType()) {
            case CHANGE:
                newDelta = new ChangeDelta(delta.getOriginal(), delta.getRevised());
                break;
            case DELETE:
                newDelta = new DeleteDelta(delta.getOriginal(), delta.getRevised());
                break;
            case INSERT:
                newDelta = new InsertDelta(delta.getOriginal(), delta.getRevised());
                break;
            default:
                throw new DiffException(String.format("Failed to convert [%s] info [%s]. Unknown type [%s]", delta
                    .getClass().getName(), Delta.class.getName(), delta.getType().toString()));
        }

        return newDelta;
    }

    @Override
    public List apply(List target) throws PatchException
    {
        List result = new LinkedList(target);
        ListIterator> it = listIterator(size());
        while (it.hasPrevious()) {
            Delta delta = it.previous();
            delta.apply(result);
        }

        return result;
    }

    @Override
    public List restore(List target) throws PatchException
    {
        List result = new LinkedList(target);
        ListIterator> it = listIterator(size());
        while (it.hasPrevious()) {
            Delta delta = it.previous();
            delta.restore(result);
        }

        return result;
    }
}