| /******************************************************************************* |
| * Copyright (c) 2008 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 124684 |
| ******************************************************************************/ |
| |
| package org.eclipse.jface.internal.databinding.viewers; |
| |
| import java.lang.reflect.Array; |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.Set; |
| |
| import org.eclipse.core.runtime.Assert; |
| import org.eclipse.jface.viewers.IElementComparer; |
| import org.eclipse.jface.viewers.StructuredViewer; |
| |
| /** |
| * A {@link Set} of elements in a {@link StructuredViewer}. Elements of the set |
| * are compared using an {@link IElementComparer} instead of |
| * {@link #equals(Object)}. |
| * <p> |
| * This class is <i>not</i> a strict implementation the {@link Set} interface. |
| * It intentionally violates the {@link Set} contract, which requires the use of |
| * {@link #equals(Object)} when comparing elements. This class is designed for |
| * use with {@link StructuredViewer} which uses {@link IElementComparer} for |
| * element comparisons. |
| * |
| * @param <E> |
| * |
| * @since 1.2 |
| */ |
| public class ViewerElementSet<E> implements Set<E> { |
| private final Set<ViewerElementWrapper<E>> wrappedSet; |
| private final IElementComparer comparer; |
| |
| /** |
| * Constructs a ViewerElementSet using the given {@link IElementComparer}. |
| * |
| * @param comparer |
| * the {@link IElementComparer} used for comparing elements. |
| */ |
| public ViewerElementSet(IElementComparer comparer) { |
| Assert.isNotNull(comparer); |
| this.wrappedSet = new HashSet<ViewerElementWrapper<E>>(); |
| this.comparer = comparer; |
| } |
| |
| /** |
| * Constructs a ViewerElementSet containing all the elements in the |
| * specified collection. |
| * |
| * @param collection |
| * the collection whose elements are to be added to this set. |
| * @param comparer |
| * the {@link IElementComparer} used for comparing elements. |
| */ |
| public ViewerElementSet(Collection<? extends E> collection, |
| IElementComparer comparer) { |
| this(comparer); |
| addAll(collection); |
| } |
| |
| public boolean add(E o) { |
| return wrappedSet.add(new ViewerElementWrapper<E>(o, comparer)); |
| } |
| |
| public boolean addAll(Collection<? extends E> c) { |
| boolean changed = false; |
| for (Iterator<? extends E> iterator = c.iterator(); iterator.hasNext();) |
| changed |= wrappedSet.add(new ViewerElementWrapper<E>(iterator |
| .next(), comparer)); |
| return changed; |
| } |
| |
| public void clear() { |
| wrappedSet.clear(); |
| } |
| |
| public boolean contains(Object o) { |
| return wrappedSet |
| .contains(new ViewerElementWrapper<Object>(o, comparer)); |
| } |
| |
| public boolean containsAll(Collection<?> c) { |
| for (Iterator<?> iterator = c.iterator(); iterator.hasNext();) |
| if (!wrappedSet.contains(new ViewerElementWrapper<Object>(iterator |
| .next(), comparer))) |
| return false; |
| return true; |
| } |
| |
| public boolean isEmpty() { |
| return wrappedSet.isEmpty(); |
| } |
| |
| public Iterator<E> iterator() { |
| final Iterator<ViewerElementWrapper<E>> wrappedIterator = wrappedSet |
| .iterator(); |
| return new Iterator<E>() { |
| public boolean hasNext() { |
| return wrappedIterator.hasNext(); |
| } |
| |
| public E next() { |
| return wrappedIterator.next().unwrap(); |
| } |
| |
| public void remove() { |
| wrappedIterator.remove(); |
| } |
| }; |
| } |
| |
| public boolean remove(Object o) { |
| return wrappedSet.remove(new ViewerElementWrapper<Object>(o, comparer)); |
| } |
| |
| public boolean removeAll(Collection<?> c) { |
| boolean changed = false; |
| for (Iterator<?> iterator = c.iterator(); iterator.hasNext();) |
| changed |= remove(iterator.next()); |
| return changed; |
| } |
| |
| public boolean retainAll(Collection<?> c) { |
| // Have to do this the slow way to ensure correct comparisons. i.e. |
| // cannot delegate to c.contains(it) since we can't be sure will |
| // compare elements the way we want. |
| boolean changed = false; |
| Object[] retainAll = c.toArray(); |
| outer: for (Iterator<?> iterator = iterator(); iterator.hasNext();) { |
| Object element = iterator.next(); |
| for (int i = 0; i < retainAll.length; i++) { |
| if (comparer.equals(element, retainAll[i])) { |
| continue outer; |
| } |
| } |
| iterator.remove(); |
| changed = true; |
| } |
| return changed; |
| } |
| |
| public int size() { |
| return wrappedSet.size(); |
| } |
| |
| public Object[] toArray() { |
| return toArray(new Object[wrappedSet.size()]); |
| } |
| |
| public Object[] toArray(Object[] a) { |
| int size = wrappedSet.size(); |
| ViewerElementWrapper[] wrappedArray = (ViewerElementWrapper[]) wrappedSet |
| .toArray(new ViewerElementWrapper[size]); |
| Object[] result = a; |
| if (a.length < size) { |
| result = (Object[]) Array.newInstance(a.getClass() |
| .getComponentType(), size); |
| } |
| for (int i = 0; i < size; i++) |
| result[i] = wrappedArray[i].unwrap(); |
| return result; |
| } |
| |
| public boolean equals(Object obj) { |
| if (obj == this) |
| return true; |
| if (!(obj instanceof Set)) |
| return false; |
| Set<?> that = (Set<?>) obj; |
| return size() == that.size() && containsAll(that); |
| } |
| |
| public int hashCode() { |
| int hash = 0; |
| for (Iterator<E> iterator = iterator(); iterator.hasNext();) { |
| E element = iterator.next(); |
| hash += element == null ? 0 : element.hashCode(); |
| } |
| return hash; |
| } |
| |
| /** |
| * Returns a Set for holding viewer elements, using the given |
| * {@link IElementComparer} for comparisons. |
| * |
| * @param comparer |
| * the element comparer to use in element comparisons. If null, |
| * the returned set will compare elements according to the |
| * standard contract for {@link Set} interface contract. |
| * @return a Set for holding viewer elements, using the given |
| * {@link IElementComparer} for comparisons. |
| */ |
| public static Set<Object> withComparer(IElementComparer comparer) { |
| if (comparer == null) |
| return new HashSet<Object>(); |
| return new ViewerElementSet(comparer); |
| } |
| } |