| /******************************************************************************* |
| * Copyright (c) 2006, 2008 IBM Corporation 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: |
| * IBM Corporation - initial API and implementation |
| * Matthew Hall - bug 208858 |
| * Matthew Hall - bug 208332 |
| *******************************************************************************/ |
| |
| package org.eclipse.core.internal.databinding.observable; |
| |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.ListIterator; |
| |
| import org.eclipse.core.databinding.observable.IChangeListener; |
| import org.eclipse.core.databinding.observable.IStaleListener; |
| import org.eclipse.core.databinding.observable.Realm; |
| import org.eclipse.core.databinding.observable.list.IListChangeListener; |
| import org.eclipse.core.databinding.observable.list.IObservableList; |
| import org.eclipse.core.runtime.Assert; |
| |
| /** |
| * Singleton empty list |
| */ |
| public class EmptyObservableList implements IObservableList { |
| |
| private static final List emptyList = Collections.EMPTY_LIST; |
| |
| private Realm realm; |
| private Object elementType; |
| |
| /** |
| * Creates an empty list. This list may be disposed multiple times |
| * without any side-effects. |
| * |
| * @param realm |
| * the realm of the constructed list |
| */ |
| public EmptyObservableList(Realm realm) { |
| this(realm, null); |
| } |
| |
| /** |
| * Creates an empty list. This list may be disposed multiple times |
| * without any side-effects. |
| * |
| * @param realm |
| * the realm of the constructed list |
| * @param elementType |
| * the element type of the constructed list |
| * @since 1.1 |
| */ |
| public EmptyObservableList(Realm realm, Object elementType) { |
| this.realm = realm; |
| this.elementType = elementType; |
| } |
| |
| public void addListChangeListener(IListChangeListener listener) { |
| // ignore |
| } |
| |
| public void removeListChangeListener(IListChangeListener listener) { |
| // ignore |
| } |
| |
| public Object getElementType() { |
| return elementType; |
| } |
| |
| public int size() { |
| checkRealm(); |
| return 0; |
| } |
| |
| void checkRealm() { |
| Assert.isTrue(realm.isCurrent(), |
| "Observable cannot be accessed outside its realm"); //$NON-NLS-1$ |
| } |
| |
| public boolean isEmpty() { |
| checkRealm(); |
| return true; |
| } |
| |
| public boolean contains(Object o) { |
| checkRealm(); |
| return false; |
| } |
| |
| public Iterator iterator() { |
| checkRealm(); |
| return emptyList.iterator(); |
| } |
| |
| public Object[] toArray() { |
| checkRealm(); |
| return emptyList.toArray(); |
| } |
| |
| public Object[] toArray(Object[] a) { |
| return emptyList.toArray(a); |
| } |
| |
| public boolean add(Object o) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean remove(Object o) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean containsAll(Collection c) { |
| checkRealm(); |
| return c.isEmpty(); |
| } |
| |
| public boolean addAll(Collection c) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean retainAll(Collection c) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean removeAll(Collection c) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public void clear() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public void addChangeListener(IChangeListener listener) { |
| } |
| |
| public void removeChangeListener(IChangeListener listener) { |
| } |
| |
| public void addStaleListener(IStaleListener listener) { |
| } |
| |
| public void removeStaleListener(IStaleListener listener) { |
| } |
| |
| public boolean isStale() { |
| checkRealm(); |
| return false; |
| } |
| |
| public void dispose() { |
| } |
| |
| public boolean addAll(int index, Collection c) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public Object get(int index) { |
| return emptyList.get(index); |
| } |
| |
| public int indexOf(Object o) { |
| return -1; |
| } |
| |
| public int lastIndexOf(Object o) { |
| return -1; |
| } |
| |
| public ListIterator listIterator() { |
| return emptyList.listIterator(); |
| } |
| |
| public ListIterator listIterator(int index) { |
| return emptyList.listIterator(index); |
| } |
| |
| public Object remove(int index) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public Object set(int index, Object element) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public Object move(int oldIndex, int newIndex) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public List subList(int fromIndex, int toIndex) { |
| return emptyList.subList(fromIndex, toIndex); |
| } |
| |
| public void add(int index, Object o) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public Realm getRealm() { |
| return realm; |
| } |
| |
| public boolean equals(Object obj) { |
| checkRealm(); |
| if (obj == this) |
| return true; |
| if (obj == null) |
| return false; |
| if (!(obj instanceof List)) |
| return false; |
| |
| return ((List) obj).isEmpty(); |
| } |
| |
| public int hashCode() { |
| checkRealm(); |
| return 1; |
| } |
| } |