remoteobject.java

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     *
     * <p>Following is the data that must be written by the
     * <code>writeExternal</code> method and read by the
     * <code>readExternal</code> method of <code>RemoteRef</code>
     * implementation classes that correspond to the each of the
     * defined external ref type names:
     *
     * <p>For <code>"UnicastRef"</code>:
     *
     * <ul>
     *
     * <li>the hostname of the referenced remote object,
     * written by {@link java.io.ObjectOutput#writeUTF(String)}
     *
     * <li>the port of the referenced remote object,
     * written by {@link java.io.ObjectOutput#writeInt(int)}
     *
     * <li>the data written as a result of calling
     * {link java.rmi.server.ObjID#write(java.io.ObjectOutput)}
     * on the <code>ObjID</code> instance contained in the reference
     *
     * <li>the boolean value <code>false</code>,
     * written by {@link java.io.ObjectOutput#writeBoolean(boolean)}
     *
     * </ul>
     *
     * <p>For <code>"UnicastRef2"</code> with a
     * <code>null</code> client socket factory:
     *
     * <ul>
     *
     * <li>the byte value <code>0x00</code>
     * (indicating <code>null</code> client socket factory),
     * written by {@link java.io.ObjectOutput#writeByte(int)}
     *
     * <li>the hostname of the referenced remote object,
     * written by {@link java.io.ObjectOutput#writeUTF(String)}
     *
     * <li>the port of the referenced remote object,
     * written by {@link java.io.ObjectOutput#writeInt(int)}
     *
     * <li>the data written as a result of calling
     * {link java.rmi.server.ObjID#write(java.io.ObjectOutput)}
     * on the <code>ObjID</code> instance contained in the reference
     *
     * <li>the boolean value <code>false</code>,
     * written by {@link java.io.ObjectOutput#writeBoolean(boolean)}
     *
     * </ul>
     * 
     * <p>For <code>"UnicastRef2"</code> with a
     * non-<code>null</code> client socket factory:
     *
     * <ul>
     *
     * <li>the byte value <code>0x01</code>
     * (indicating non-<code>null</code> client socket factory),
     * written by {@link java.io.ObjectOutput#writeByte(int)}
     *
     * <li>the hostname of the referenced remote object,
     * written by {@link java.io.ObjectOutput#writeUTF(String)}
     *
     * <li>the port of the referenced remote object,
     * written by {@link java.io.ObjectOutput#writeInt(int)}
     *
     * <li>a client socket factory (object of type
     * <code>java.rmi.server.RMIClientSocketFactory</code>),
     * written by passing it to an invocation of
     * <code>writeObject</code> on the stream instance
     *
     * <li>the data written as a result of calling
     * {link java.rmi.server.ObjID#write(java.io.ObjectOutput)}
     * on the <code>ObjID</code> instance contained in the reference
     *
     * <li>the boolean value <code>false</code>,
     * written by {@link java.io.ObjectOutput#writeBoolean(boolean)}
     *
     * </ul>
     *
     * <p>For <code>"ActivatableRef"</code> with a
     * <code>null</code> nested remote reference:
     *
     * <ul>
     *
     * <li>an instance of
     * <code>java.rmi.activation.ActivationID</code>,
     * written by passing it to an invocation of
     * <code>writeObject</code> on the stream instance
     *
     * <li>a zero-length string (<code>""</code>),
     * written by {@link java.io.ObjectOutput#writeUTF(String)}
     *
     * </ul>
     *
     * <p>For <code>"ActivatableRef"</code> with a
     * non-<code>null</code> nested remote reference:
     *
     * <ul>
     *
     * <li>an instance of
     * <code>java.rmi.activation.ActivationID</code>,
     * written by passing it to an invocation of
     * <code>writeObject</code> on the stream instance
     *
     * <li>the external ref type name of the nested remote reference,
     * which must be <code>"UnicastRef2"</code>,
     * written by {@link java.io.ObjectOutput#writeUTF(String)}
     *
     * <li>the external form of the nested remote reference,
     * written by invoking its <code>writeExternal</code> method
     * with the stream instance
     * (see the description of the external form for
     * <code>"UnicastRef2"</code> above)
     *
     * </ul>
     *
     * <p>For <code>"UnicastServerRef"</code>,
     * <code>"UnicastServerRef2"</code>, and
     * <code>"ActivatableServerRef"</code>, no data is written by the
     * <code>writeExternal</code> method or read by the
     * <code>readExternal</code> method.
     */
    private void writeObject(java.io.ObjectOutputStream out)
	throws java.io.IOException, java.lang.ClassNotFoundException
    {
	if (ref == null) {
	    throw new java.rmi.MarshalException("Invalid remote object");
	} else {
	    String refClassName = ref.getRefClass(out);
	    if (refClassName == null || refClassName.length() == 0) {
		/*
		 * No reference class name specified, so serialize
		 * remote reference.
		 */
		out.writeUTF("");
		out.writeObject(ref);
	    } else {
		/*
		 * Built-in reference class specified, so delegate
		 * to reference to write out its external form.
		 */
		out.writeUTF(refClassName);
		ref.writeExternal(out);
	    }
	}
    }

    /**
     * <code>readObject</code> for custom serialization.
     *
     * <p>This method reads this object's serialized form for this class
     * as follows:
     *
     * <p>The <code>readUTF</code> method is invoked on <code>in</code>
     * to read the external ref type name for the <code>RemoteRef</code>
     * instance to be filled in to this object's <code>ref</code> field.
     * If the string returned by <code>readUTF</code> has length zero,
     * the <code>readObject</code> method is invoked on <code>in</code>,
     * and than the value returned by <code>readObject</code> is cast to
     * <code>RemoteRef</code> and this object's <code>ref</code> field is
     * set to that value.
     * Otherwise, this object's <code>ref</code> field is set to a
     * <code>RemoteRef</code> instance that is created of an
     * implementation-specific class corresponding to the external ref
     * type name returned by <code>readUTF</code>, and then
     * the <code>readExternal</code> method is invoked on
     * this object's <code>ref</code> field.
     *
     * <p>If the external ref type name is
     * <code>"UnicastRef"</code>, <code>"UnicastServerRef"</code>,
     * <code>"UnicastRef2"</code>, <code>"UnicastServerRef2"</code>,
     * <code>"ActivatableRef"</code>, or
     * <code>"ActivatableServerRef"</code>, a corresponding
     * implementation-specific class must be found, and its
     * <code>readExternal</code> method must read the serial data
     * for that external ref type name as specified to be written
     * in the <b>serialData</b> documentation for this class.
     * If the external ref type name is any other string (of non-zero
     * length), a <code>ClassNotFoundException</code> will be thrown,
     * unless the implementation provides an implementation-specific
     * class corresponding to that external ref type name, in which
     * case this object's <code>ref</code> field will be set to an
     * instance of that implementation-specific class.
     */
    private void readObject(java.io.ObjectInputStream in) 
	throws java.io.IOException, java.lang.ClassNotFoundException
    {
	try {
	    String refClassName = in.readUTF();
	    if (refClassName == null || refClassName.length() == 0) {
		/*
		 * No reference class name specified, so construct
		 * remote reference from its serialized form.
		 */
		ref = (RemoteRef) in.readObject();
	    } else {
		/*
		 * Built-in reference class specified, so delegate
		 * to reference to initialize its fields  from its
		 * external form.
		 */
		Class refClass = Class.forName(RemoteRef.packagePrefix + "." +
					       refClassName);
		ref = (RemoteRef) refClass.newInstance();
		ref.readExternal(in);
	    }
	} catch (InstantiationException e) {
	    throw new UnmarshalException("Unable to create remote reference",
					 e);
	} catch (IllegalAccessException e) {
	    throw new UnmarshalException("Illegal access creating remote reference");
	}
    }
}