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- package java.io;
- /*
- * Copyright (c) 1996, 2005, 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.
- */
- /**
- * Serializability of a class is enabled by the class implementing the
- * java.io.Serializable interface. Classes that do not implement this
- * interface will not have any of their state serialized or
- * deserialized. All subtypes of a serializable class are themselves
- * serializable. The serialization interface has no methods or fields
- * and serves only to identify the semantics of being serializable. <p>
- *
- * To allow subtypes of non-serializable classes to be serialized, the
- * subtype may assume responsibility for saving and restoring the
- * state of the supertype's public, protected, and (if accessible)
- * package fields. The subtype may assume this responsibility only if
- * the class it extends has an accessible no-arg constructor to
- * initialize the class's state. It is an error to declare a class
- * Serializable if this is not the case. The error will be detected at
- * runtime. <p>
- *
- * During deserialization, the fields of non-serializable classes will
- * be initialized using the public or protected no-arg constructor of
- * the class. A no-arg constructor must be accessible to the subclass
- * that is serializable. The fields of serializable subclasses will
- * be restored from the stream. <p>
- *
- * When traversing a graph, an object may be encountered that does not
- * support the Serializable interface. In this case the
- * NotSerializableException will be thrown and will identify the class
- * of the non-serializable object. <p>
- *
- * Classes that require special handling during the serialization and
- * deserialization process must implement special methods with these exact
- * signatures: <p>
- *
- * <PRE>
- * private void writeObject(java.io.ObjectOutputStream out)
- * throws IOException
- * private void readObject(java.io.ObjectInputStream in)
- * throws IOException, ClassNotFoundException;
- * private void readObjectNoData()
- * throws ObjectStreamException;
- * </PRE>
- *
- * <p>The writeObject method is responsible for writing the state of the
- * object for its particular class so that the corresponding
- * readObject method can restore it. The default mechanism for saving
- * the Object's fields can be invoked by calling
- * out.defaultWriteObject. The method does not need to concern
- * itself with the state belonging to its superclasses or subclasses.
- * State is saved by writing the individual fields to the
- * ObjectOutputStream using the writeObject method or by using the
- * methods for primitive data types supported by DataOutput.
- *
- * <p>The readObject method is responsible for reading from the stream and
- * restoring the classes fields. It may call in.defaultReadObject to invoke
- * the default mechanism for restoring the object's non-static and
- * non-transient fields. The defaultReadObject method uses information in
- * the stream to assign the fields of the object saved in the stream with the
- * correspondingly named fields in the current object. This handles the case
- * when the class has evolved to add new fields. The method does not need to
- * concern itself with the state belonging to its superclasses or subclasses.
- * State is saved by writing the individual fields to the
- * ObjectOutputStream using the writeObject method or by using the
- * methods for primitive data types supported by DataOutput.
- *
- * <p>The readObjectNoData method is responsible for initializing the state of
- * the object for its particular class in the event that the serialization
- * stream does not list the given class as a superclass of the object being
- * deserialized. This may occur in cases where the receiving party uses a
- * different version of the deserialized instance's class than the sending
- * party, and the receiver's version extends classes that are not extended by
- * the sender's version. This may also occur if the serialization stream has
- * been tampered; hence, readObjectNoData is useful for initializing
- * deserialized objects properly despite a "hostile" or incomplete source
- * stream.
- *
- * <p>Serializable classes that need to designate an alternative object to be
- * used when writing an object to the stream should implement this
- * special method with the exact signature: <p>
- *
- * <PRE>
- * ANY-ACCESS-MODIFIER Object writeReplace() throws ObjectStreamException;
- * </PRE><p>
- *
- * This writeReplace method is invoked by serialization if the method
- * exists and it would be accessible from a method defined within the
- * class of the object being serialized. Thus, the method can have private,
- * protected and package-private access. Subclass access to this method
- * follows java accessibility rules. <p>
- *
- * Classes that need to designate a replacement when an instance of it
- * is read from the stream should implement this special method with the
- * exact signature.<p>
- *
- * <PRE>
- * ANY-ACCESS-MODIFIER Object readResolve() throws ObjectStreamException;
- * </PRE><p>
- *
- * This readResolve method follows the same invocation rules and
- * accessibility rules as writeReplace.<p>
- *
- * The serialization runtime associates with each serializable class a version
- * number, called a serialVersionUID, which is used during deserialization to
- * verify that the sender and receiver of a serialized object have loaded
- * classes for that object that are compatible with respect to serialization.
- * If the receiver has loaded a class for the object that has a different
- * serialVersionUID than that of the corresponding sender's class, then
- * deserialization will result in an {@link InvalidClassException}. A
- * serializable class can declare its own serialVersionUID explicitly by
- * declaring a field named <code>"serialVersionUID"</code> that must be static,
- * final, and of type <code>long</code>:<p>
- *
- * <PRE>
- * ANY-ACCESS-MODIFIER static final long serialVersionUID = 42L;
- * </PRE>
- *
- * If a serializable class does not explicitly declare a serialVersionUID, then
- * the serialization runtime will calculate a default serialVersionUID value
- * for that class based on various aspects of the class, as described in the
- * Java(TM) Object Serialization Specification. However, it is <em>strongly
- * recommended</em> that all serializable classes explicitly declare
- * serialVersionUID values, since the default serialVersionUID computation is
- * highly sensitive to class details that may vary depending on compiler
- * implementations, and can thus result in unexpected
- * <code>InvalidClassException</code>s during deserialization. Therefore, to
- * guarantee a consistent serialVersionUID value across different java compiler
- * implementations, a serializable class must declare an explicit
- * serialVersionUID value. It is also strongly advised that explicit
- * serialVersionUID declarations use the <code>private</code> modifier where
- * possible, since such declarations apply only to the immediately declaring
- * class--serialVersionUID fields are not useful as inherited members. Array
- * classes cannot declare an explicit serialVersionUID, so they always have
- * the default computed value, but the requirement for matching
- * serialVersionUID values is waived for array classes.
- *
- * @author unascribed
- * @see java.io.ObjectOutputStream
- * @see java.io.ObjectInputStream
- * @see java.io.ObjectOutput
- * @see java.io.ObjectInput
- * @see java.io.Externalizable
- * @since JDK1.1
- */
- extern interface Serializable
- {
-
- }
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