Externalizable.java

/*
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 * particular file as subject to the "Classpath" exception as provided
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package com.sun.lwuit.io;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

/**
 * Similar to the Java SE externalizable interface this interface allows an object
 * to declare itself as externalizable for serialization. However, due to the lack
 * of reflection and use of obfuscation these objects must be registered with the
 * Util class.
 * Notice that all externalizable objects must have a default public constructor.
 *
 * @author Shai Almog
 */
public interface Externalizable {
    /**
     * Returns the version for the current persistance code, the version will be
     * pased to internalized thus allowing the internalize method to recognize
     * classes persisted in older revisions
     *
     * @return version number for the persistant code
     */
    public int getVersion();

    /**
     * Allows us to store an object state, this method must be implemented
     * in order to save the state of an object
     *
     * @param out the stream into which the object must be serialized
     * @throws java.io.IOException the method may throw an exception
     */
    public void externalize(DataOutputStream out) throws IOException;

    /**
     * Loads the object from the input stream and allows deserialization
     *
     * @param version the version the class returned during the externalization processs
     * @param in the input stream used to load the class
     * @throws java.io.IOException the method may throw an exception
     */
    public void internalize(int version, DataInputStream in) throws IOException;

    /**
     * The object id must be unique, it is used to identify the object when loaded
     * even when it is obfuscated.
     *
     * @return a unique id
     */
    public String getObjectId();
}