/*
 This file is part of the software framework JStatCom, 
 a library for building applications for data based analysis.

 Copyright (C) 2007  Markus Kraetzig

 This library 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 library 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 library; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 USA
 */
package com.jstatcom.util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

/**
 * Helper methods for (de)serialization and de/encoding to strings.
 * 
 * @author Markus Kraetzig 
 */
public final class SerializationHelper {

    /**
     * Serializes o to a byte array representation.
     * 
     * @param o
     *            object to serialize
     * @return byte array with serialized o
     * @throws IllegalArgumentException
     *             if (!(o instanceof Serializable))
     */
    public static byte[] getByteFromObject(Object o) {
        if (!(o instanceof Serializable))
            throw new IllegalArgumentException("Argument was not Serializable.");

        ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
        try {
            ObjectOutputStream out = new ObjectOutputStream(byteOut);
            out.writeObject(o);
            out.close();
            return byteOut.toByteArray();
        } catch (IOException e) {
            throw new RuntimeException("Error setting  Object " + o
                    + " to byte[].", e);
        }

    }

    /**
     * Deserializes an object from the byte array representation of the
     * serialized version.
     * 
     * @param byteArray
     *            byte array representation of serialized object
     * @return deserialized object
     */
    public static  T getObjectFromByteArray(byte[] byteArray) {

        ByteArrayInputStream byteIn = new ByteArrayInputStream(byteArray);
        try {
            ObjectInputStream in = new ObjectInputStream(byteIn);
            T rtn = (T) in.readObject();
            in.close();
            return rtn;
        } catch (Exception e) {
            throw new RuntimeException("Error retrieving Object from byte[].",
                    e);
        }

    }

    /**
     * Base64 encoding of serializable objects.
     * 
     * @param o
     *            serializable object, may be null
     * @return Base64 eoncoded string
     * @throws IllegalArgumentException
     *             if (o != null && !(o instanceof Serializable))
     */
    public static String encode(Object o) {
        if (o == null)
            return null;
        if (!(o instanceof Serializable))
            throw new IllegalArgumentException("Argument was not Serializable.");

        String encGZDontBreakLines = Base64.encodeObject((Serializable) o,
                Base64.GZIP | Base64.DONT_BREAK_LINES);

        return encGZDontBreakLines;

    }

    /**
     * Decode Base64 encoded string (with encode).
     * 
     * @param encodedString
     *            may be null
     * @return instance of T or null if argument
     *         was null
     */
    public static  T decode(String encodedString) {
        if (encodedString == null)
            return null;
        return (T) Base64.decodeToObject(encodedString);
    }

}