/*
 * eXist Open Source Native XML Database
 * Copyright (C) 2001-2015 The eXist Project
 *
 * http://exist-db.org
 *
 * This program 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
 * of the License, or (at your option) any later version.
 *
 * This program 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 program; if not, write to the Free Software Foundation
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
package org.exist.storage.dom;

import java.nio.ByteBuffer;

import org.exist.storage.DBBroker;
import org.exist.storage.NativeBroker;
import org.exist.storage.journal.AbstractLoggable;
import org.exist.storage.journal.LogException;
import org.exist.storage.txn.Txn;

public class UpdateLinkLoggable extends AbstractLoggable {
    protected long pageNum;
    protected int offset;
    protected long link;
    protected long oldLink;
    private DOMFile domDb = null;

    public UpdateLinkLoggable(final Txn transaction, final long pageNum, final int offset, final long link, final long oldLink) {
        super(DOMFile.LOG_UPDATE_LINK, transaction.getId());
        this.pageNum = pageNum;
        this.offset = offset;
        this.link = link;
        this.oldLink = oldLink;
    }

    public UpdateLinkLoggable(final DBBroker broker, final long transactId) {
        super(DOMFile.LOG_UPDATE_LINK, transactId);
        this.domDb = ((NativeBroker) broker).getDOMFile();
    }

    @Override
    public void write(final ByteBuffer out) {
        out.putInt((int) pageNum);
        out.putShort((short) offset);
        out.putLong(link);
        out.putLong(oldLink);
    }

    @Override
    public void read(final ByteBuffer in) {
        pageNum = in.getInt();
        offset = in.getShort();
        link = in.getLong();
        oldLink = in.getLong();
    }

    @Override
    public int getLogSize() {
        return 22;
    }

    @Override
    public void redo() throws LogException {
        domDb.redoUpdateLink(this);
    }

    @Override
    public void undo() throws LogException {
        domDb.undoUpdateLink(this);
    }

    @Override
    public String dump() {
        return super.dump() + " - updated link on page: " + pageNum + " at offset: " + offset;
    }
}