eu.numberfour.n4js.ts.scoping.ValidatingScope.java Source code

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Here is the source code for eu.numberfour.n4js.ts.scoping.ValidatingScope.java

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/**
 * Copyright (c) 2016 NumberFour AG.
 * 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:
 *   NumberFour AG - Initial API and implementation
 */
package eu.numberfour.n4js.ts.scoping;

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

import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;

/**
 * A scope implementation that filters the result of {@link #getAllElements()} by a
 * given criteria.
 *
 * The {@link ValidatingScope} should always be the leaf element in the scope chain.
 */
public class ValidatingScope implements IScope {

    private final IScope delegate;
    private final Predicate<? super IEObjectDescription> allElementsFilter;

    /**
     * Creates a new scope that filters the result of {@link #getAllElements()} by
     * the given criteria. Only elements that evaluate the predicate to {@code true}
     * are returned.
     *
     * @param delegate the scope that does the heavy lifting.
     * @param allElementsFilter the filter for the elements.
     */
    public ValidatingScope(IScope delegate, Predicate<? super IEObjectDescription> allElementsFilter) {
        this.delegate = delegate;
        this.allElementsFilter = allElementsFilter;
    }

    @Override
    public IEObjectDescription getSingleElement(QualifiedName name) {
        return delegate.getSingleElement(name);
    }

    @Override
    public Iterable<IEObjectDescription> getElements(QualifiedName name) {
        return delegate.getElements(name);
    }

    @Override
    public IEObjectDescription getSingleElement(EObject object) {
        return delegate.getSingleElement(object);
    }

    @Override
    public Iterable<IEObjectDescription> getElements(EObject object) {
        return delegate.getElements(object);
    }

    /**
     * Returns a filtered iterable of descriptions. Only elements that evaluate to
     * {@code true} when passed to the {@link #allElementsFilter} are returned.
     */
    @Override
    public Iterable<IEObjectDescription> getAllElements() {
        return Iterables.filter(delegate.getAllElements(), allElementsFilter);
    }

}