org.eclipse.incquery.runtime.localsearch.operations.extend.nobase.ExtendToEStructuralFeatureSource.java Source code

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Here is the source code for org.eclipse.incquery.runtime.localsearch.operations.extend.nobase.ExtendToEStructuralFeatureSource.java

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/*******************************************************************************
 * Copyright (c) 2010-2015, Marton Bur, Zoltan Ujhelyi, Akos Horvath, Istvan Rath and Daniel Varro
 * 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:
 *   Marton Bur, Zoltan Ujhelyi, Akos Horvath - initial API and implementation
 *******************************************************************************/
package org.eclipse.incquery.runtime.localsearch.operations.extend.nobase;

import java.util.Collection;
import java.util.List;

import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EReference;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.incquery.runtime.base.api.NavigationHelper;
import org.eclipse.incquery.runtime.localsearch.MatchingFrame;
import org.eclipse.incquery.runtime.localsearch.exceptions.LocalSearchException;
import org.eclipse.incquery.runtime.localsearch.matcher.ISearchContext;
import org.eclipse.incquery.runtime.localsearch.operations.extend.ExtendOperation;

import com.google.common.collect.Iterators;
import com.google.common.collect.Lists;

/**
 * Iterates over all sources of {@link EStructuralFeature} using an {@link NavigationHelper EMF-IncQuery Base indexer}.
 * It is assumed that the indexer is initialized for the selected {@link EStructuralFeature}.
 * 
 */
public class ExtendToEStructuralFeatureSource extends ExtendOperation<Object> {

    private int targetPosition;
    private EStructuralFeature feature;

    public ExtendToEStructuralFeatureSource(int sourcePosition, int targetPosition, EStructuralFeature feature) {
        super(sourcePosition);
        this.targetPosition = targetPosition;
        this.feature = feature;
    }

    public EStructuralFeature getFeature() {
        return feature;
    }

    /* (non-Javadoc)
     * @see org.eclipse.incquery.runtime.localsearch.operations.ISearchOperation#onInitialize(org.eclipse.incquery.runtime.localsearch.MatchingFrame)
     */
    @SuppressWarnings("unchecked")
    @Override
    public void onInitialize(MatchingFrame frame, ISearchContext context) throws LocalSearchException {
        if (!(feature instanceof EReference)) {
            throw new LocalSearchException("Without base index, inverse navigation only possible along "
                    + "EReferences with defined EOpposite.");
        }
        EReference oppositeFeature = ((EReference) feature).getEOpposite();
        if (oppositeFeature == null) {
            throw new LocalSearchException(
                    "Feature has no EOpposite, so cannot do inverse navigation " + feature.toString());
        }
        try {
            final EObject value = (EObject) frame.getValue(targetPosition);
            if (!oppositeFeature.getEContainingClass().isSuperTypeOf(value.eClass())) {
                // TODO planner should ensure the proper supertype relation
                it = Iterators.emptyIterator();
                return;
            }
            final Object featureValue = value.eGet(oppositeFeature);
            if (oppositeFeature.isMany()) {
                if (featureValue != null) {
                    final Collection<Object> objectCollection = (Collection<Object>) featureValue;
                    it = objectCollection.iterator();
                } else {
                    it = Iterators.emptyIterator();
                }
            } else {
                if (featureValue != null) {
                    it = Iterators.singletonIterator(featureValue);
                } else {
                    it = Iterators.emptyIterator();
                }
            }
        } catch (ClassCastException e) {
            throw new LocalSearchException("Invalid feature target in parameter" + Integer.toString(targetPosition),
                    e);
        }
    }

    @Override
    public String toString() {
        StringBuilder builder = new StringBuilder();
        builder.append("extend to source ").append(feature.getContainerClass().getSimpleName()).append('.')
                .append(feature.getName());
        return builder.toString();
    }

    @Override
    public List<Integer> getVariablePositions() {
        return Lists.asList(position, targetPosition, new Integer[0]);
    }

}