org.eclipse.emf.compare.ide.ui.internal.actions.group.MetamodelGroupProvider.java Source code

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Here is the source code for org.eclipse.emf.compare.ide.ui.internal.actions.group.MetamodelGroupProvider.java

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/*******************************************************************************
 * Copyright (c) 2012 Obeo.
 * 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:
 *     Obeo - initial API and implementation
 *******************************************************************************/
package org.eclipse.emf.compare.ide.ui.internal.actions.group;

import static com.google.common.base.Predicates.alwaysTrue;

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

import java.util.List;
import java.util.Map;

import org.eclipse.emf.compare.AttributeChange;
import org.eclipse.emf.compare.Comparison;
import org.eclipse.emf.compare.Diff;
import org.eclipse.emf.compare.Match;
import org.eclipse.emf.compare.ReferenceChange;
import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EObject;

/**
 * This implementation of a {@link DifferenceGroupProvider} will be used to group the differences by their
 * metamodel element : all diffs that apply to a Class, all diffs that apply on a reference...
 * 
 * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
 */
public class MetamodelGroupProvider implements DifferenceGroupProvider {
    /**
     * {@inheritDoc}
     * 
     * @see org.eclipse.emf.compare.ide.ui.internal.actions.group.DifferenceGroupProvider#getGroups(org.eclipse.emf.compare.Comparison)
     */
    public Iterable<? extends DifferenceGroup> getGroups(Comparison comparison) {
        final List<Diff> diffs = comparison.getDifferences();

        final Map<EClass, List<Diff>> diffByEClass = Maps.newLinkedHashMap();
        for (Diff candidate : diffs) {
            final EClass target;
            if (candidate instanceof ReferenceChange) {
                if (((ReferenceChange) candidate).getReference().isContainment()) {
                    final EObject parentMatch = candidate.getMatch().eContainer();
                    if (parentMatch instanceof Match) {
                        target = findEClass((Match) parentMatch);
                    } else {
                        target = findEClass(candidate.getMatch());
                    }
                } else {
                    target = findEClass(candidate.getMatch());
                }
            } else if (candidate instanceof AttributeChange) {
                target = findEClass(candidate.getMatch());
            } else {
                // Ignore this possibility for now.
                continue;
            }

            List<Diff> diffsForEClass = diffByEClass.get(target);
            if (diffsForEClass == null) {
                diffsForEClass = Lists.newArrayList();
                diffByEClass.put(target, diffsForEClass);
            }
            diffsForEClass.add(candidate);
        }

        final List<DifferenceGroup> groups = Lists.newArrayList();
        for (Map.Entry<EClass, List<Diff>> entry : diffByEClass.entrySet()) {
            groups.add(new DefaultDifferenceGroup(comparison, entry.getValue(), alwaysTrue(),
                    entry.getKey().getName()));
        }

        return groups;
    }

    private EClass findEClass(Match match) {
        final EClass eClass;
        if (match.getOrigin() != null) {
            eClass = match.getOrigin().eClass();
        } else if (match.getRight() != null) {
            eClass = match.getRight().eClass();
        } else {
            /*
             * All three sides null means that something went awry. Might as well throw the exception from
             * here.
             */
            eClass = match.getLeft().eClass();
        }
        return eClass;
    }
}