/*
 * Copyright 2004 - 2008 Christian Sprajc. All rights reserved.
 *
 * This file is part of PowerFolder.
 *
 * PowerFolder is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 *
 * PowerFolder 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PowerFolder. If not, see <http://www.gnu.org/licenses/>.
 *
 * $Id$
 */
package de.dal33t.powerfolder.message;

import java.io.IOException;

import de.dal33t.powerfolder.light.FileInfo;
import de.dal33t.powerfolder.util.Format;
import de.dal33t.powerfolder.util.Reject;
import de.dal33t.powerfolder.util.Validate;

/**
 * A file chunk, part of a upload / donwload
 * 
 * @author <a href="mailto:totmacher@powerfolder.com">Christian Sprajc </a>
 * @version $Revision: 1.6 $
 */
public class FileChunk extends Message implements LimitBandwidth {
    private static final long serialVersionUID = 100L;

    public FileInfo file;
    public long offset;
    public byte[] data;

    public FileChunk() {
        // Serialisation constructor
    }

    public FileChunk(FileInfo file, long offset, byte[] data) {
        this.file = file;
        this.offset = offset;
        this.data = data;
        validate();
    }

    public String toString() {
        return "FileChunk: " + file + " ("
            + Format.formatDecimal(file.getSize()) + " total bytes), offset: "
            + offset + ", chunk size: " + data.length;
    }

    // Overridden due to validation!
    private void readObject(java.io.ObjectInputStream in) throws IOException,
        ClassNotFoundException
    {
        in.defaultReadObject();
        validate();
    }

    /**
     * 
     */
    private void validate() {
        Reject.noNullElements(file, data);
        Validate.isTrue(offset >= 0);
        Validate.isTrue(offset + data.length <= file.getSize());
    }
}