| /* |
| * Copyright (C) 2009 The Guava Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.common.collect; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| /** |
| * GWT emulation of {@link SingletonImmutableSet}. |
| * |
| * @author Hayward Chan |
| */ |
| final class SingletonImmutableSet<E> extends ImmutableSet<E> { |
| |
| // This reference is used both by the custom field serializer, and by the |
| // GWT compiler to infer the elements of the lists that needs to be |
| // serialized. |
| // |
| // Although this reference is non-final, it doesn't change after set creation. |
| E element; |
| |
| SingletonImmutableSet(E element) { |
| this.element = checkNotNull(element); |
| } |
| |
| @Override |
| public int size() { |
| return 1; |
| } |
| |
| @Override |
| public UnmodifiableIterator<E> iterator() { |
| return Iterators.singletonIterator(element); |
| } |
| |
| @Override |
| public boolean contains(Object object) { |
| return element.equals(object); |
| } |
| } |