org.eclipse.xtext.scoping.impl.MultimapBasedScope.java Source code

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Here is the source code for org.eclipse.xtext.scoping.impl.MultimapBasedScope.java

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/*******************************************************************************
 * Copyright (c) 2010 itemis AG (http://www.itemis.eu) 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
 *******************************************************************************/
package org.eclipse.xtext.scoping.impl;

import java.util.Collection;
import java.util.Collections;

import org.eclipse.xtext.naming.QualifiedName;
import org.eclipse.xtext.resource.IEObjectDescription;
import org.eclipse.xtext.scoping.IScope;

import com.google.common.collect.LinkedHashMultimap;
import com.google.common.collect.Multimap;

/**
 * A scope implemented using a {@link Multimap}. 
 * 
 * This implementation assumes, that the keys of the {@link Multimap} are the keys of the contained {@link org.eclipse.xtext.resource.EObjectDescription}s
 * as well as the name.
 * 
 * When looking up elements using {@link #getElements(QualifiedName)} this implementation looks up the the elements from the map, hence are much 
 * more efficient for many {@link IEObjectDescription}s.
 *   
 * @author Sven Efftinge - Initial contribution and API 
 * @author Sebastian Zarnekow
 */
public class MultimapBasedScope extends AbstractScope {

    public static IScope createScope(IScope parent, Iterable<IEObjectDescription> descriptions,
            boolean ignoreCase) {
        Multimap<QualifiedName, IEObjectDescription> map = null;
        for (IEObjectDescription description : descriptions) {
            if (map == null)
                map = LinkedHashMultimap.create(5, 2);
            if (ignoreCase)
                map.put(description.getName().toLowerCase(), description);
            else
                map.put(description.getName(), description);
        }
        if (map == null || map.isEmpty()) {
            return parent;
        }
        return new MultimapBasedScope(parent, map, ignoreCase);
    }

    private Multimap<QualifiedName, IEObjectDescription> elements;

    protected MultimapBasedScope(IScope parent, Multimap<QualifiedName, IEObjectDescription> elements,
            boolean ignoreCase) {
        super(parent, ignoreCase);
        this.elements = elements;
    }

    @Override
    protected Iterable<IEObjectDescription> getAllLocalElements() {
        return elements.values();
    }

    @Override
    protected Iterable<IEObjectDescription> getLocalElementsByName(QualifiedName name) {
        QualifiedName query = name;
        if (isIgnoreCase()) {
            query = name.toLowerCase();
        }
        if (elements.containsKey(query)) {
            Collection<IEObjectDescription> result = elements.get(query);
            return result;
        }
        return Collections.emptyList();
    }

    @Override
    protected boolean isShadowed(IEObjectDescription fromParent) {
        QualifiedName name = fromParent.getName();
        if (isIgnoreCase()) {
            name = name.toLowerCase();
        }
        boolean result = elements.containsKey(name);
        return result;
    }

    //   public Multimap<QualifiedName, IEObjectDescription> getMap() {
    //      return elements;
    //   }

}