/*
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();
	}

}