/*******************************************************************************
* Copyright (c) 2012, 2016 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.rcp.ui.internal.structuremergeviewer.filters;
import static com.google.common.base.Predicates.alwaysFalse;
import static com.google.common.base.Predicates.not;
import static com.google.common.base.Predicates.or;
import static com.google.common.collect.Iterables.any;
import static com.google.common.collect.Sets.newLinkedHashSet;
import com.google.common.base.Predicate;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.common.eventbus.EventBus;
import java.util.Collection;
import java.util.Set;
import org.eclipse.emf.common.notify.Adapter;
import org.eclipse.emf.common.notify.Notifier;
import org.eclipse.emf.compare.Conflict;
import org.eclipse.emf.compare.Match;
import org.eclipse.emf.compare.MatchResource;
import org.eclipse.emf.compare.rcp.ui.internal.structuremergeviewer.filters.impl.DifferenceFilterChange;
import org.eclipse.emf.compare.rcp.ui.internal.structuremergeviewer.groups.provider.GroupItemProviderAdapter;
import org.eclipse.emf.compare.rcp.ui.structuremergeviewer.filters.IDifferenceFilter;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.edit.tree.TreeNode;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.ui.progress.PendingUpdateAdapter;
/**
* This will be used by the structure viewer to filter out its list of differences according to a number of
* provided predicates.
* <p>
* <b>Note</b> that this filter acts as an "OR" predicate between all provided ones, and that filters are
* "exclude" filters. Basically, that means if the user selects two filters, any difference that applies for
* any of these two filters will be <i>hidden</i> from the view, contrarily to "classic" {@link ViewerFilter}
* that act as "AND" predicates for "include" filters, forcing any displayed element to meet the criterion of
* all provided filters.
* </p>
*
* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
* @since 4.0
*/
public class StructureMergeViewerFilter extends ViewerFilter {
/** A predicate use by default that always returns false. */
public static final Predicate<? super EObject> DEFAULT_PREDICATE = alwaysFalse();
/** The set of predicates known by this filter. */
private final Set<Predicate<? super EObject>> predicates;
/** The set of selected filters known by this filter. */
private final Set<IDifferenceFilter> selectedDifferenceFilters;
/** The set of unselected filters known by this filter. */
private final Set<IDifferenceFilter> unselectedDifferenceFilters;
/** The set of active filters known by this filter. */
private final Set<IDifferenceFilter> activeDifferenceFilters;
/** The {@link EventBus} associated with this filter. */
private final EventBus eventBus;
/**
* The predicate used by this StructureMergeViewerFilter.
*/
private final Predicate<? super EObject> viewerPredicate = new Predicate<EObject>() {
public boolean apply(EObject eObject) {
final boolean ret;
if (aggregatedPredicate.apply(eObject)) {
Collection<EObject> eContents = eObject.eContents();
if (!eContents.isEmpty() && eObject instanceof TreeNode) {
EObject data = ((TreeNode)eObject).getData();
if (data instanceof Match || data instanceof Conflict || data instanceof MatchResource) {
ret = any(eContents, viewerPredicate);
} else {
ret = true;
}
} else {
ret = true;
}
} else {
ret = false;
}
return ret;
}
};
/**
* A predicate that aggregates the selected state predicates of selected filters and the unselected state
* predicates of unselected filters.
*/
private Predicate<? super EObject> aggregatedPredicate;
/**
* Constructs the difference filter.
*
* @param eventBus
* The {@link EventBus} which will be associated with this filter.
*/
public StructureMergeViewerFilter(EventBus eventBus) {
this.eventBus = eventBus;
this.predicates = newLinkedHashSet();
this.selectedDifferenceFilters = newLinkedHashSet();
this.unselectedDifferenceFilters = newLinkedHashSet();
this.activeDifferenceFilters = newLinkedHashSet();
this.aggregatedPredicate = DEFAULT_PREDICATE;
}
/**
* {@inheritDoc}
*
* @see org.eclipse.jface.viewers.ViewerFilter#select(org.eclipse.jface.viewers.Viewer, java.lang.Object,
* java.lang.Object)
*/
@Override
public boolean select(Viewer viewer, Object parentElement, Object element) {
if (predicates.isEmpty()) {
return true;
}
final boolean result;
if (element instanceof GroupItemProviderAdapter) {
Collection<?> children = ((GroupItemProviderAdapter)element).getChildren(element);
result = any(Iterables.filter(children, EObject.class), viewerPredicate);
} else if (element instanceof PendingUpdateAdapter) {
result = true;
} else if (element instanceof Adapter) {
Notifier notifier = ((Adapter)element).getTarget();
if (notifier instanceof EObject) {
EObject eObject = (EObject)notifier;
result = viewerPredicate.apply(eObject);
} else {
result = true;
}
} else if (element instanceof EObject) {
result = viewerPredicate.apply((EObject)element);
} else {
result = true;
}
return result;
}
/**
* Add the predicate of the given {@link IDifferenceFilter}.
*
* @param filter
* The given {@link IDifferenceFilter}.
*/
public void addFilter(IDifferenceFilter filter) {
boolean changed = predicates.remove(filter.getPredicateWhenUnselected());
changed = predicates.add(filter.getPredicateWhenSelected()) || changed;
changed = selectedDifferenceFilters.add(filter) || changed;
changed = unselectedDifferenceFilters.remove(filter) || changed;
if (changed) {
aggregatedPredicate = computeAggregatedPredicate();
eventBus.post(new DifferenceFilterChange(aggregatedPredicate, selectedDifferenceFilters,
unselectedDifferenceFilters));
}
}
/**
* Computes the aggregated predicates composed of selected state predicates of selected filters and
* unselected state predicates of unselected filters.
*
* @return an aggregated predicates composed of selected state predicates of selected filters and
* unselected state predicates of unselected filters.
*/
private Predicate<? super EObject> computeAggregatedPredicate() {
return not(or(predicates));
}
/**
* Remove the predicate of the given {@link IDifferenceFilter}.
*
* @param filter
* The given {@link IDifferenceFilter}.
*/
public void removeFilter(IDifferenceFilter filter) {
boolean changed = predicates.add(filter.getPredicateWhenUnselected());
changed |= predicates.remove(filter.getPredicateWhenSelected());
changed |= unselectedDifferenceFilters.add(filter);
changed |= selectedDifferenceFilters.remove(filter);
if (changed) {
aggregatedPredicate = computeAggregatedPredicate();
eventBus.post(new DifferenceFilterChange(aggregatedPredicate, selectedDifferenceFilters,
unselectedDifferenceFilters));
}
}
/**
* Init this StructureMergeViewerFilter.
*
* @param selectedFilters
* the set of selected filters known by this filter.
* @param unselectedFilters
* the set of unselected filters known by this filter.
* @param activeFilters
* the set of activated filters known by this filter.
*/
public void init(Collection<IDifferenceFilter> selectedFilters,
Collection<IDifferenceFilter> unselectedFilters, Collection<IDifferenceFilter> activeFilters) {
boolean changed = false;
if (!predicates.isEmpty()) {
predicates.clear();
changed = true;
}
activeDifferenceFilters.addAll(activeFilters);
for (IDifferenceFilter filter : selectedFilters) {
changed = predicates.add(filter.getPredicateWhenSelected()) || changed;
changed = selectedDifferenceFilters.add(filter) || changed;
}
for (IDifferenceFilter filter : unselectedFilters) {
changed = predicates.add(filter.getPredicateWhenUnselected()) || changed;
changed = unselectedDifferenceFilters.add(filter) || changed;
}
if (changed) {
aggregatedPredicate = computeAggregatedPredicate();
eventBus.post(new DifferenceFilterChange(aggregatedPredicate, selectedDifferenceFilters,
unselectedDifferenceFilters));
}
}
/**
* Returns the set of selected filters known by this filter.
*
* @return the selectedDifferenceFilters the set of selected filters known by this filter.
*/
public Set<IDifferenceFilter> getSelectedDifferenceFilters() {
return selectedDifferenceFilters;
}
/**
* Returns the set of activated filters known by this filter.
*
* @return the activatedDifferenceFilters the set of activated filters known by this filter.
*/
public Set<IDifferenceFilter> getActiveDifferenceFilters() {
return activeDifferenceFilters;
}
/**
* Returns the set of unselected filters known by this viewer.
*
* @return the unselectedDifferenceFilters the set of unselected filters known by this viewer.
*/
public Set<IDifferenceFilter> getUnSelectedDifferenceFilters() {
return ImmutableSet.copyOf(unselectedDifferenceFilters);
}
/**
* Returns the predicate that aggregates the selected state predicates of selected filters and the
* unselected state predicates of unselected filters.
*
* @return the predicate that aggregates the selected state predicates of selected filters and the
* unselected state predicates of unselected filters.
*/
public Predicate<? super EObject> getAggregatedPredicate() {
return aggregatedPredicate;
}
}