/*

 Wotonomy: OpenStep design patterns for pure Java applications.

 Copyright (C) 2000 Blacksmith, Inc.

 This library is free software; you can redistribute it and/or

 modify it under the terms of the GNU Lesser General Public

 License as published by the Free Software Foundation; either

 version 2.1 of the License, or (at your option) any later version.

 This library 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

 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public

 License along with this library; if not, see http://www.gnu.org

 */

 package net.wotonomy.web;

 import java.util.Iterator;

 import java.util.List;

 import net.wotonomy.foundation.NSMutableArray;

 /**

 * This class represents a parent node in an element tree.

 * It has no content in itself, and exists only to forward

 * messages to each of its children, in turn.

 * Package access only, as it is not in the specification.

 *

 * @author michael@mpowers.net

 * @author $Author: cgruber $

 * @version $Revision: 905 $

 */

 class WOParentElement extends WOElement

 {

         NSMutableArray children;

         /**

         * Default constructor.  

         */

         public WOParentElement()

         {

                 children = new NSMutableArray();

         }

         /**

         * Returns an element with the specified children.

         */

         public WOParentElement( List childElements )

         {

                 this();

                 children.addAll( childElements );

         }

     /**

     * Package access only.  Called to initialize the component with 

     * the proper context before the start of the request-response cycle.

     * If the context has a current component, that component becomes

     * this component's parent.

     */

     void ensureAwakeInContext (WOContext aContext)

     {

         WOElement element;

             Iterator it = children.iterator();

             while ( it.hasNext() )

             {

             element = (WOElement) it.next();

             aContext.pushElement( element );

                     element.ensureAwakeInContext( aContext );

             aContext.popElement();

             }

     }

         /**

         * Forwards this message to all child elements.

         */

     public void takeValuesFromRequest (

             WORequest aRequest, WOContext aContext)

     {

             WOElement element;

 //        aContext.incrementLastElementIDComponent();

         aContext.appendZeroElementIDComponent();

             Iterator it = children.iterator();

             while ( it.hasNext() )

             {

             element = (WOElement) it.next();

             aContext.pushElement( element );

             aContext.incrementLastElementIDComponent();

                     element.takeValuesFromRequest( aRequest, aContext );

             aContext.popElement();

             }

         aContext.deleteLastElementIDComponent();

     }

     /**

         * Forwards this message to all child elements,

         * returning the first non-null result.

     */

     public WOActionResults invokeAction (

             WORequest aRequest, WOContext aContext)

     {

             WOElement element;

 //        aContext.incrementLastElementIDComponent();

         aContext.appendZeroElementIDComponent();

             WOActionResults result = null;

             Iterator it = children.iterator();

             while ( it.hasNext() )

             {

                     element = (WOElement) it.next();

             aContext.pushElement( element );

             aContext.incrementLastElementIDComponent();

                     result = element.invokeAction( aRequest, aContext );

             aContext.popElement();

                     if ( result != null ) break;

             }

         aContext.deleteLastElementIDComponent();

             return result;

     }

     /**

         * Forwards this message to all child elements.

     */

     public void appendToResponse (WOResponse aResponse, WOContext aContext)

     {

             WOElement element;

 //        aContext.incrementLastElementIDComponent();

         aContext.appendZeroElementIDComponent();

             // for each child element

             Iterator it = children.iterator();

             while ( it.hasNext() )

             {

                     element = (WOElement) it.next();

             aContext.pushElement( element );

             aContext.incrementLastElementIDComponent();

                     // forward the message

                     element.appendToResponse( 

                             aResponse, aContext );

             aContext.popElement();

             }

         aContext.deleteLastElementIDComponent();

     }

     public WOResponse generateResponse() 

     {

         WOResponse r = new WOResponse();

         return r;

     }

     public String toString()

     {

         StringBuffer result = new StringBuffer();

         result.append( "[WOParentElement: " );

             // for each child element

             Iterator it = children.iterator();

             while ( it.hasNext() )

             {

             result.append( "[ " );

             result.append( it.next().toString() );

             result.append( " ]" );

             }

         result.append( " ]" );

         return result.toString();

     }

 }