/*
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();
    }
    
}