/*

  * Copyright (C) 1998-2000 Semiotek Inc.  All Rights Reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted under the terms of either of the following

  * Open Source licenses:

  *

  * The GNU General Public License, version 2, or any later version, as

  * published by the Free Software Foundation

  * (http://www.fsf.org/copyleft/gpl.html);

  *

  *  or

  *

  * The Semiotek Public License (http://webmacro.org/LICENSE.)

  *

  * This software is provided "as is", with NO WARRANTY, not even the

  * implied warranties of fitness to purpose, or merchantability. You

  * assume all risks and liabilities associated with its use.

  *

  * See www.webmacro.org for more information on the WebMacro project.

  */

 package org.webmacro.engine;

 import org.webmacro.Context;

 import org.webmacro.Macro;

 import org.webmacro.PropertyException;

 /**

  * Operate on bean properties of an existing macro; used when a Macro

  * is passed as an argument to a macro

  * @author Brian Goetz

  * @since 1.1

  */

 public class MacroPropertyVariable extends Variable

 {

     private Macro value;

     /**

      * No special initialization

      */

     MacroPropertyVariable (Macro value, Object names[])

     {

         super(names);

         this.value = value;

     }

     /**

      * Look up my value in the corresponding Map, possibly using introspection,

      * and return it

      * @exception PropertyException If the property does not exist

      */

     public final Object getValue (Context context)

             throws PropertyException

     {

         Object v = value.evaluate(context);

         if (v == null)

             throw new PropertyException.NullValueException(_names[0].toString());

         else

             return context.getBroker()

                     ._propertyOperators.getProperty(context, v, _names, 1);

     }

     /**

      * Look up my the value of this variable in the specified Map, possibly

      * using introspection, and set it to the supplied value.

      * @exception PropertyException If the property does not exist

      */

     public final void setValue (Context context, Object newValue)

             throws PropertyException

     {

         throw new PropertyException("Cannot set properties of a constant");

     }

     /**

      * Return a string representation naming the variable for

      * debugging purposes.

      */

     public final String toString ()

     {

         return "macro-property:" + getVariableName();

     }

 }