org.eclipse.osbp.xtext.oxtype/src/org/eclipse/osbp/xtext/oxtype/scoping/eobject/CachingEObjectScope.xtend

/**
 *                                                                            
 * Copyright (c) 2011, 2015 - Lunifera GmbH (Gross Enzersdorf, Austria), Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
 * 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:
 *         Florian Pirchner - Initial implementation
 *   
 *  This copyright notice shows up in the generated Java code
 *
 */
package org.eclipse.osbp.xtext.oxtype.scoping.eobject

import com.google.common.collect.Maps
import java.util.Collections
import java.util.Map
import org.eclipse.osbp.xtext.oxtype.scoping.ScopingMetrics
import org.eclipse.xtext.naming.QualifiedName
import org.eclipse.xtext.resource.IEObjectDescription
import org.eclipse.xtext.scoping.IScope
import org.eclipse.xtext.scoping.impl.AbstractScope

class CachingEObjectScope extends AbstractScope {

	private final Map<QualifiedName, IEObjectDescription> cache;

	private Object cacheKey

	private ScopingMetrics metrics

	new(Object cacheKey, ScopingMetrics metrics, IScope parent, boolean ignoreCase) {
		super(parent, ignoreCase)
		this.cacheKey = cacheKey;
		this.metrics = metrics;
		this.cache = Maps.newHashMapWithExpectedSize(50);
	}

	override IEObjectDescription getSingleElement(QualifiedName name) {
		var IEObjectDescription cached = cache.get(name);
		if (cached == null) {
			if (cache.containsKey(name)) {
				return null;
			}
			cached = super.getSingleElement(name);

			// install an indicator adapter to indicate the eobject, that is was scoped import scopings
			cache.put(name, cached);
		} else {
			metrics.cacheHit(cacheKey, cached.name.toString)
		}
		return cached;
	}

	override Iterable<IEObjectDescription> getElements(QualifiedName name) {
		val Iterable<IEObjectDescription> elements = super.getElements(name)
		elements.forEach [
			if (!cache.containsKey(it.name)) {
				cache.put(it.name, it)
			}
		]
		return elements
	}

	override protected Iterable<IEObjectDescription> getAllLocalElements() {
		return Collections.emptyList
	}

}