From 6c80c45e3010bfe992b41dd8800d2c4b65e0d5ef Mon Sep 17 00:00:00 2001
From: Tom Tromey <tromey@gcc.gnu.org>
Date: Fri, 19 May 2000 17:55:34 +0000
Subject: Jumbo patch:
* Imported beans and serialization
* Updated IA-64 port
* Miscellaneous bug fixes
From-SVN: r34028
---
libjava/java/io/Externalizable.java | 98 +++++++++++++++++++++++++++++++++++++
1 file changed, 98 insertions(+)
create mode 100644 libjava/java/io/Externalizable.java
(limited to 'libjava/java/io/Externalizable.java')
diff --git a/libjava/java/io/Externalizable.java b/libjava/java/io/Externalizable.java
new file mode 100644
index 0000000..045df86
--- /dev/null
+++ b/libjava/java/io/Externalizable.java
@@ -0,0 +1,98 @@
+/* Externalizable.java -- Interface for saving and restoring object data
+ Copyright (C) 1998 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath 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; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 USA.
+
+As a special exception, if you link this library with other files to
+produce an executable, this library does not by itself cause the
+resulting executable to be covered by the GNU General Public License.
+This exception does not however invalidate any other reasons why the
+executable file might be covered by the GNU General Public License. */
+
+
+package java.io;
+
+/**
+ * This interface provides a way that classes can completely control how
+ * the data of their object instances are written and read to and from
+ * streams. It has two methods which are used to write the data to a stream
+ * and to read the data from a stream. The read method must read the data
+ * in exactly the way it was written by the write method.
+ * <p>
+ * Note that classes which implement this interface must take into account
+ * that all superclass data must also be written to the stream as well.
+ * The class implementing this interface must figure out how to make that
+ * happen.
+ * <p>
+ * This interface can be used to provide object persistence. When an
+ * object is to be stored externally, the <code>writeExternal</code> method is
+ * called to save state. When the object is restored, an instance is
+ * created using the default no-argument constructor and the
+ * <code>readExternal</code> method is used to restore the state.
+ *
+ * @version 0.0
+ *
+ * @author Aaron M. Renn (arenn@urbanophile.com)
+ */
+public abstract interface Externalizable extends Serializable
+{
+
+/**
+ * This method restores an object's state by reading in the instance data
+ * for the object from the passed in stream. Note that this stream is not
+ * a subclass of <code>InputStream</code>, but rather is a class that implements
+ * the <code>ObjectInput</code> interface. That interface provides a mechanism for
+ * reading in Java data types from a stream.
+ * <p>
+ * Note that this method must be compatible with <code>writeExternal</code>.
+ * It must read back the exact same types that were written by that
+ * method in the exact order they were written.
+ * <p>
+ * If this method needs to read back an object instance, then the class
+ * for that object must be found and loaded. If that operation fails,
+ * then this method throws a <code>ClassNotFoundException</code>
+ *
+ * @param in An <code>ObjectInput</code> instance for reading in the object state
+ *
+ * @exception ClassNotFoundException If the class of an object being restored cannot be found
+ * @exception IOException If any other error occurs
+ */
+public abstract void
+readExternal(ObjectInput in) throws ClassNotFoundException, IOException;
+
+/*************************************************************************/
+
+/**
+ * This method is responsible for writing the instance data of an object
+ * to the passed in stream. Note that this stream is not a subclass of
+ * <code>OutputStream</code>, but rather is a class that implements the
+ * <code>ObjectOutput</code> interface. That interface provides a number of methods
+ * for writing Java data values to a stream.
+ * <p>
+ * Not that the implementation of this method must be coordinated with
+ * the implementation of <code>readExternal</code>.
+ *
+ * @param out An <code>ObjectOutput</code> instance for writing the object state
+ *
+ * @exception IOException If an error occurs
+ */
+public abstract void
+writeExternal(ObjectOutput out) throws IOException;
+
+} // interface Externalizable
+
--
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