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diff --git a/src/share/classes/sun/rmi/log/LogHandler.java b/src/share/classes/sun/rmi/log/LogHandler.java
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+++ b/src/share/classes/sun/rmi/log/LogHandler.java
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+/*
+ * Copyright 1997-2001 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package sun.rmi.log;
+
+import java.io.*;
+import sun.rmi.server.MarshalOutputStream;
+import sun.rmi.server.MarshalInputStream;
+
+/**
+ * A LogHandler represents snapshots and update records as serializable
+ * objects.
+ *
+ * This implementation does not know how to create an initial snaphot or
+ * apply an update to a snapshot.  The client must specifiy these methods
+ * via a subclass.
+ *
+ * @see ReliableLog
+ *
+ * @author Ann Wollrath
+ */
+public abstract
+class LogHandler {
+
+    /**
+     * Creates a LogHandler for a ReliableLog.
+     */
+    public LogHandler() {}
+
+    /**
+     * Creates and returns the initial state of data structure that needs
+     * to be stably stored. This method is called when a ReliableLog is
+     * created.
+     * @return the initial state
+     * @exception Exception can raise any exception
+     */
+    public abstract
+    Object initialSnapshot() throws Exception;
+
+    /**
+     * Writes the snapshot object to a stream.  This callback is
+     * invoked when the client calls the snaphot method of ReliableLog.
+     * @param out the output stream
+     * @param value the snapshot
+     * @exception Exception can raise any exception
+     */
+    public
+    void snapshot(OutputStream out, Object value) throws Exception {
+        MarshalOutputStream s = new MarshalOutputStream(out);
+        s.writeObject(value);
+        s.flush();
+    }
+
+    /**
+     * Read the snapshot object from a stream and returns the snapshot.
+     * This callback is invoked when the client calls the recover method
+     * of ReliableLog.
+     * @param in the input stream
+     * @return the state (snapshot)
+     * @exception Exception can raise any exception
+     */
+
+    public
+    Object recover(InputStream in) throws Exception {
+        MarshalInputStream s = new MarshalInputStream(in);
+        return s.readObject();
+    }
+
+    /**
+     * Writes the representation (a serializable object) of an update
+     * to a stream.  This callback is invoked when the client calls the
+     * update method of ReliableLog.
+     * @param out the output stream
+     * @param value the snapshot
+     * @exception Exception can raise any exception
+     */
+    public
+    void writeUpdate(LogOutputStream out, Object value) throws Exception {
+
+        MarshalOutputStream s = new MarshalOutputStream(out);
+        s.writeObject(value);
+        s.flush();
+    }
+
+    /**
+     * Reads a stably logged update (a serializable object) from a
+     * stream.  This callback is invoked during recovery, once for
+     * every record in the log.  After reading the update, this method
+     * invokes the applyUpdate (abstract) method in order to obtain
+     * the new snapshot value.  It then returns the new snapshot.
+     *
+     * @param in the input stream
+     * @param state the current state
+     * @return the new state
+     * @exception Exception can raise any exception
+     */
+    public
+    Object readUpdate(LogInputStream in, Object state) throws Exception {
+        MarshalInputStream  s = new MarshalInputStream(in);
+        return applyUpdate(s.readObject(), state);
+    }
+
+    /**
+     * Reads a stably logged update (a serializable object) from a stream.
+     * This callback is invoked during recovery, once for every record in the
+     * log.  After reading the update, this method is invoked in order to
+     * obtain the new snapshot value.  The method should apply the update
+     * object to the current state <code>state</code> and return the new
+     * state (the new snapshot value).
+     * @param update the update object
+     * @param state the current state
+     * @return the new state
+     * @exception Exception can raise any exception
+     */
+    public abstract
+    Object applyUpdate(Object update, Object state) throws Exception;
+
+}