/*
 * @(#)ObjectHolder.java	1.25 00/02/02
 *
 * Copyright 1996-2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */

package org.omg.CORBA;

import org.omg.CORBA.portable.Streamable;
import org.omg.CORBA.portable.InputStream;
import org.omg.CORBA.portable.OutputStream;


/**
 * A Holder class for a CORBA object reference (a value of type
 * <code>org.omg.CORBA.Object</code>).  It is usually
 * used to store "out" and "inout" parameters in IDL methods.
 * If an IDL method signature has a CORBA Object reference as an "out"
 * or "inout" parameter, the programmer must pass an instance of
 * <code>ObjectHolder</code> as the corresponding
 * parameter in the method invocation; for "inout" parameters, the programmer
 * must also fill the "in" value to be sent to the server.
 * Before the method invocation returns, the ORB will fill in the
 * value corresponding to the "out" value returned from the server.
 * <P>
 * If <code>myObjectHolder</code> is an instance of <code>ObjectHolder</code>,
 * the value stored in its <code>value</code> field can be accessed with
 * <code>myObjectHolder.value</code>.
 *
 * @version	1.14, 09/09/97
 * @since       JDK1.2
 */
public final class ObjectHolder implements Streamable {
    /**
     * The <code>Object</code> value held by this <code>ObjectHolder</code>
     * object.
     */
    public Object value;

    /**
     * Constructs a new <code>ObjectHolder</code> object with its
     * <code>value</code> field initialized to <code>null</code>.
     */
    public ObjectHolder() {
    }
    
    /**
     * Constructs a new <code>ObjectHolder</code> object with its
     * <code>value</code> field initialized to the given
     * <code>Object</code>.
     * @param initial the <code>Object</code> with which to initialize
     *                the <code>value</code> field of the newly-created
     *                <code>ObjectHolder</code> object
     */
    public ObjectHolder(Object initial) {
	value = initial;
    }

    /**
     * Reads from <code>input</code> and initalizes the value in
     * this <code>ObjectHolder</code> object
     * with the unmarshalled data.
     *
     * @param input the InputStream containing CDR formatted data from the wire.
     */
    public void _read(InputStream input) {
	value = input.read_Object();
    }

    /**
     * Marshals to <code>output</code> the value in 
     * this <code>ObjectHolder</code> object.
     *
     * @param output the OutputStream which will contain the CDR formatted data.
     */
    public void _write(OutputStream output) {
	output.write_Object(value);
    }

    /**
     * Returns the TypeCode corresponding to the value held in 
     * this <code>ObjectHolder</code> object
     *
     * @return    the TypeCode of the value held in
     *            this <code>ObjectHolder</code> object
     */
    public org.omg.CORBA.TypeCode _type() {
	return org.omg.CORBA.ORB.init().get_primitive_tc(TCKind.tk_objref);
    }
}