/*******************************************************************************
 * Copyright (c) 2003, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jst.j2ee.internal.validation;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IProject;
import org.eclipse.jdt.core.IPackageFragmentRoot;
import org.eclipse.jem.workbench.utility.JemProjectUtilities;
import org.eclipse.jst.j2ee.internal.project.J2EEProjectUtilities;
import org.eclipse.wst.common.componentcore.ComponentCore;
import org.eclipse.wst.common.componentcore.resources.IVirtualComponent;
import org.eclipse.wst.validation.internal.IProjectValidationHelper;

public class ProjectValidationHelper implements IProjectValidationHelper {

	private static IContainer[] EMPTY_RESULT = new IContainer[] {};
	private static ProjectValidationHelper INSTANCE;
	private IContainer[] outputs;
	private IContainer[] sources;
	
	public static ProjectValidationHelper getInstance(){
		if (INSTANCE == null)
			INSTANCE = new ProjectValidationHelper();
		return INSTANCE;
	}
	public void disposeInstance(){
		INSTANCE = null;
	}
	private IContainer[] getCachedOutputContainers(IProject project) {
		if (outputs != null)
			return outputs;
		if (project == null || JemProjectUtilities.getJavaProject(project)==null) {
			outputs = EMPTY_RESULT;
			return EMPTY_RESULT;
		}
		IVirtualComponent comp = ComponentCore.createComponent(project);
		if (comp == null || !comp.exists()) {
			outputs = EMPTY_RESULT;
			return EMPTY_RESULT;
		}
		outputs = J2EEProjectUtilities.getOutputContainers(project);
		return outputs;
	
	}
	public IContainer[] getOutputContainers(IProject project) {
		ProjectValidationHelper inst = getInstance();
		if(inst == null){
			return null;
		}
		return getInstance().getCachedOutputContainers(project);
	}
	
	private IContainer[] getCachedSourceContainers(IProject project) {
		if (sources != null)
			return sources;
		if (project == null || JemProjectUtilities.getJavaProject(project)==null) {
			sources = EMPTY_RESULT;
			return EMPTY_RESULT;
		}
		IVirtualComponent comp = ComponentCore.createComponent(project);
		if (comp == null || !comp.exists()) {
			sources = EMPTY_RESULT;
			return EMPTY_RESULT;
		}
		IPackageFragmentRoot[] roots = J2EEProjectUtilities.getSourceContainers(project);
		List result = new ArrayList();
		for (int i=0; i<roots.length; i++) {
			if (roots[i].getResource() != null && roots[i].getResource() instanceof IContainer)
				result.add(roots[i].getResource());
		}
		sources = (IContainer[]) result.toArray(new IContainer[result.size()]);
		return sources;
		
	}
	public IContainer[] getSourceContainers(IProject project) {
		return getInstance().getCachedSourceContainers(project);
	}

}