| /* |
| * Copyright (c) 1996, 2004, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.io; |
| |
| import java.io.ObjectOutput; |
| import java.io.ObjectInput; |
| |
| /** |
| * Only the identity of the class of an Externalizable instance is |
| * written in the serialization stream and it is the responsibility |
| * of the class to save and restore the contents of its instances. |
| * |
| * The writeExternal and readExternal methods of the Externalizable |
| * interface are implemented by a class to give the class complete |
| * control over the format and contents of the stream for an object |
| * and its supertypes. These methods must explicitly |
| * coordinate with the supertype to save its state. These methods supersede |
| * customized implementations of writeObject and readObject methods.<br> |
| * |
| * Object Serialization uses the Serializable and Externalizable |
| * interfaces. Object persistence mechanisms can use them as well. Each |
| * object to be stored is tested for the Externalizable interface. If |
| * the object supports Externalizable, the writeExternal method is called. If the |
| * object does not support Externalizable and does implement |
| * Serializable, the object is saved using |
| * ObjectOutputStream. <br> When an Externalizable object is |
| * reconstructed, an instance is created using the public no-arg |
| * constructor, then the readExternal method called. Serializable |
| * objects are restored by reading them from an ObjectInputStream.<br> |
| * |
| * An Externalizable instance can designate a substitution object via |
| * the writeReplace and readResolve methods documented in the Serializable |
| * interface.<br> |
| * |
| * @author unascribed |
| * @see java.io.ObjectOutputStream |
| * @see java.io.ObjectInputStream |
| * @see java.io.ObjectOutput |
| * @see java.io.ObjectInput |
| * @see java.io.Serializable |
| * @since 1.1 |
| */ |
| public interface Externalizable extends java.io.Serializable { |
| /** |
| * The object implements the writeExternal method to save its contents |
| * by calling the methods of DataOutput for its primitive values or |
| * calling the writeObject method of ObjectOutput for objects, strings, |
| * and arrays. |
| * |
| * @serialData Overriding methods should use this tag to describe |
| * the data layout of this Externalizable object. |
| * List the sequence of element types and, if possible, |
| * relate the element to a public/protected field and/or |
| * method of this Externalizable class. |
| * |
| * @param out the stream to write the object to |
| * @exception IOException Includes any I/O exceptions that may occur |
| */ |
| void writeExternal(ObjectOutput out) throws IOException; |
| |
| /** |
| * The object implements the readExternal method to restore its |
| * contents by calling the methods of DataInput for primitive |
| * types and readObject for objects, strings and arrays. The |
| * readExternal method must read the values in the same sequence |
| * and with the same types as were written by writeExternal. |
| * |
| * @param in the stream to read data from in order to restore the object |
| * @exception IOException if I/O errors occur |
| * @exception ClassNotFoundException If the class for an object being |
| * restored cannot be found. |
| */ |
| void readExternal(ObjectInput in) throws IOException, ClassNotFoundException; |
| } |