org.eclipselabs.spray.xtext.scoping.AliasingScope.java Source code

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Here is the source code for org.eclipselabs.spray.xtext.scoping.AliasingScope.java

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/** ****************************************************************************
 * Copyright (c)  The Spray Project.
 * 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:
 *     Spray Dev Team - initial API and implementation
 **************************************************************************** */
package org.eclipselabs.spray.xtext.scoping;

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

import com.google.common.base.Function;
import com.google.common.base.Predicates;
import com.google.common.collect.Iterables;

/**
 * A scope that aliases the IEObjectDescriptions of the wrapped scope.
 * 
 * @author Karsten Thoms (karsten.thoms@itemis.de)
 */
public class AliasingScope extends AbstractScope {
    public static final Function<QualifiedName, QualifiedName> LAST_SEGMENT = new Function<QualifiedName, QualifiedName>() {
        @Override
        public QualifiedName apply(QualifiedName input) {
            return QualifiedName.create(input.getLastSegment());
        }
    };

    private Iterable<IEObjectDescription> elements;

    /**
     * Creates the aliasing scope.
     * 
     * @param parent
     *            Parent scope
     * @param aliasingFunction
     *            A function that maps qualified names to their aliases
     */
    public AliasingScope(IScope parent, final Function<QualifiedName, QualifiedName> aliasingFunction) {
        super(IScope.NULLSCOPE, false);
        final Function<IEObjectDescription, IEObjectDescription> toAliasedDescription = new Function<IEObjectDescription, IEObjectDescription>() {
            @Override
            public IEObjectDescription apply(IEObjectDescription input) {
                // the alias function might result into null, return null in this case. The nulls will be filtered afterwards
                final QualifiedName alias = aliasingFunction.apply(input.getQualifiedName());
                return alias != null ? new AliasedEObjectDescription(alias, input) : null;
            }
        };
        elements = Iterables.filter(Iterables.transform(parent.getAllElements(), toAliasedDescription),
                Predicates.notNull());
    }

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