/*
 * Copyright (c) 2003-2004 Christopher Lenz and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     Christopher Lenz - initial API and implementation
 * 
 * $Id: CssOutlineContentProvider.java,v 1.1 2004-09-02 18:11:49 jsurfer Exp $
 */

package net.sourceforge.phpeclipse.css.ui.internal.outline;

import net.sourceforge.phpeclipse.css.core.model.IRule;
import net.sourceforge.phpeclipse.css.core.model.IStyleSheet;

import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.Viewer;

/**
 * Content provider for the CSS outline page.
 */
public class CssOutlineContentProvider implements ITreeContentProvider {

	// Instance Variables ------------------------------------------------------

	/**
	 * The parsed style sheet.
	 */
	private IStyleSheet styleSheet;

	// ITreeContentProvider Implementation -------------------------------------

	/*
	 * ITreeContentProvider#getChildren(Object)
	 */
	public Object[] getChildren(Object parentElement) {
		if (parentElement instanceof IRule) {
			return ((IRule) parentElement).getChildren();
		}
		return new Object[0];
	}

	/*
	 * @see ITreeContentProvider#getParent(Object)
	 */
	public Object getParent(Object element) {
		if (element instanceof IRule) {
			return ((IRule) element).getParent();
		}
		return null;
	}

	/*
	 * @see ITreeContentProvider#hasChildren(Object)
	 */
	public boolean hasChildren(Object element) {
		return getChildren(element).length > 0;
	}

	/*
	 * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(Object)
	 */
	public Object[] getElements(Object inputElement) {
		if (styleSheet != null) {
			return styleSheet.getRules();
		}
		return new Object[0];
	}

	/*
	 * @see org.eclipse.jface.viewers.IContentProvider#dispose()
	 */
	public void dispose() {
		styleSheet = null;
	}

	/*
	 * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(Viewer, Object, Object)
	 */
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
		if (oldInput != newInput) {
			if (oldInput instanceof IStyleSheet) {
				styleSheet = null;
			}
			if (newInput instanceof IStyleSheet) {
				IStyleSheet newStyleSheet = (IStyleSheet) newInput;
				styleSheet = newStyleSheet;
			}	   
		}
	}

}