/*******************************************************************************
* Copyright (c) 2008, 2015 Matthew Hall and others.
* 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:
* Matthew Hall - initial API and implementation (bug 215531)
* Matthew Hall - bug 230267
* (through ObservableViewerElementSet.java)
* Matthew Hall - bug 262269
* Stefan Xenos <sxenos@gmail.com> - Bug 335792
******************************************************************************/
package org.eclipse.core.internal.databinding.identity;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.Set;
import org.eclipse.core.databinding.observable.Diffs;
import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.set.AbstractObservableSet;
import org.eclipse.core.databinding.observable.set.IObservableSet;
/**
* An {@link IObservableSet} of elements where elements are added, removed and
* compared by identity. Elements of the set are compared using <code>==</code>
* instead of {@link #equals(Object)}.
* <p>
* This class is <i>not</i> a strict implementation the {@link IObservableSet}
* interface. It intentionally violates the {@link Set} contract, which requires
* the use of {@link #equals(Object)} when comparing elements.
*
* @param <E>
* the type of the elements in this set
*
* @since 1.2
*/
public class IdentityObservableSet<E> extends AbstractObservableSet<E> {
private Set<E> wrappedSet;
private Object elementType;
/**
* Constructs an IdentityObservableSet on the given {@link Realm}.
*
* @param realm
* the realm of the constructed set.
* @param elementType
* the element type of the constructed set.
*/
public IdentityObservableSet(Realm realm, Object elementType) {
super(realm);
this.wrappedSet = new IdentitySet<>();
this.elementType = elementType;
}
@Override
protected Set<E> getWrappedSet() {
return wrappedSet;
}
@Override
public Object getElementType() {
return elementType;
}
@Override
public Iterator<E> iterator() {
getterCalled();
final Iterator<E> wrappedIterator = wrappedSet.iterator();
return new Iterator<E>() {
E last;
@Override
public boolean hasNext() {
getterCalled();
return wrappedIterator.hasNext();
}
@Override
public E next() {
getterCalled();
return last = wrappedIterator.next();
}
@Override
public void remove() {
getterCalled();
wrappedIterator.remove();
Set<E> emptySet = Collections.emptySet();
fireSetChange(Diffs.createSetDiff(emptySet, Collections.singleton(last)));
}
};
}
@Override
public boolean add(E o) {
getterCalled();
boolean changed = wrappedSet.add(o);
if (changed) {
Set<E> emptySet = Collections.emptySet();
fireSetChange(Diffs.createSetDiff(Collections.singleton(o), emptySet));
}
return changed;
}
@Override
public boolean addAll(Collection<? extends E> c) {
getterCalled();
Set<E> additions = new IdentitySet<>();
for (E element : c) {
if (wrappedSet.add(element))
additions.add(element);
}
boolean changed = !additions.isEmpty();
if (changed) {
Set<E> emptySet = Collections.emptySet();
fireSetChange(Diffs.createSetDiff(additions, emptySet));
}
return changed;
}
@SuppressWarnings("unchecked")
@Override
public boolean remove(Object o) {
getterCalled();
boolean changed = wrappedSet.remove(o);
if (changed) {
Set<E> additions = Collections.emptySet();
fireSetChange(Diffs.createSetDiff(additions,
Collections.singleton((E) o)));
}
return changed;
}
@SuppressWarnings("unchecked")
@Override
public boolean removeAll(Collection<?> c) {
getterCalled();
Set<E> removals = new IdentitySet<>();
for (Object element : c) {
if (wrappedSet.remove(element)) {
removals.add((E) element);
}
}
boolean changed = !removals.isEmpty();
if (changed) {
Set<E> additions = Collections.emptySet();
fireSetChange(Diffs.createSetDiff(additions, removals));
}
return changed;
}
@Override
public boolean retainAll(Collection<?> c) {
getterCalled();
Set<E> removals = new IdentitySet<>();
Object[] toRetain = c.toArray();
outer: for (Iterator<E> iterator = wrappedSet.iterator(); iterator.hasNext();) {
E element = iterator.next();
// Cannot rely on c.contains(element) because we must compare
// elements using IElementComparer.
for (int i = 0; i < toRetain.length; i++) {
if (element == toRetain[i])
continue outer;
}
iterator.remove();
removals.add(element);
}
boolean changed = !removals.isEmpty();
if (changed) {
Set<E> additions = Collections.emptySet();
fireSetChange(Diffs.createSetDiff(additions, removals));
}
return changed;
}
@Override
public void clear() {
getterCalled();
if (!wrappedSet.isEmpty()) {
Set<E> removals = wrappedSet;
wrappedSet = new IdentitySet<>();
Set<E> additions = Collections.emptySet();
fireSetChange(Diffs.createSetDiff(additions, removals));
}
}
}