| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 java.util; |
| |
| import java.io.Serializable; |
| |
| /** |
| * LinkedHashSet is a variant of HashSet. Its entries are kept in a |
| * doubly-linked list. The iteration order is the order in which entries were |
| * inserted. |
| * <p> |
| * Null elements are allowed, and all the optional Set operations are supported. |
| * <p> |
| * Like HashSet, LinkedHashSet is not thread safe, so access by multiple threads |
| * must be synchronized by an external mechanism such as |
| * {@link Collections#synchronizedSet(Set)}. |
| * |
| * @since 1.4 |
| */ |
| public class LinkedHashSet<E> extends HashSet<E> implements Set<E>, Cloneable, |
| Serializable { |
| |
| private static final long serialVersionUID = -2851667679971038690L; |
| |
| /** |
| * Constructs a new empty instance of {@code LinkedHashSet}. |
| */ |
| public LinkedHashSet() { |
| super(new LinkedHashMap<E, HashSet<E>>()); |
| } |
| |
| /** |
| * Constructs a new instance of {@code LinkedHashSet} with the specified |
| * capacity. |
| * |
| * @param capacity |
| * the initial capacity of this {@code LinkedHashSet}. |
| */ |
| public LinkedHashSet(int capacity) { |
| super(new LinkedHashMap<E, HashSet<E>>(capacity)); |
| } |
| |
| /** |
| * Constructs a new instance of {@code LinkedHashSet} with the specified |
| * capacity and load factor. |
| * |
| * @param capacity |
| * the initial capacity. |
| * @param loadFactor |
| * the initial load factor. |
| */ |
| public LinkedHashSet(int capacity, float loadFactor) { |
| super(new LinkedHashMap<E, HashSet<E>>(capacity, loadFactor)); |
| } |
| |
| /** |
| * Constructs a new instance of {@code LinkedHashSet} containing the unique |
| * elements in the specified collection. |
| * |
| * @param collection |
| * the collection of elements to add. |
| */ |
| public LinkedHashSet(Collection<? extends E> collection) { |
| super(new LinkedHashMap<E, HashSet<E>>(collection.size() < 6 ? 11 |
| : collection.size() * 2)); |
| for (E e : collection) { |
| add(e); |
| } |
| } |
| |
| /* overrides method in HashMap */ |
| @Override |
| HashMap<E, HashSet<E>> createBackingMap(int capacity, float loadFactor) { |
| return new LinkedHashMap<E, HashSet<E>>(capacity, loadFactor); |
| } |
| } |