001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.collections4.set;
018
019import java.util.Set;
020
021import org.apache.commons.collections4.collection.AbstractCollectionDecorator;
022
023/**
024 * Decorates another <code>Set</code> to provide additional behaviour.
025 * <p>
026 * Methods are forwarded directly to the decorated set.
027 * </p>
028 *
029 * @param <E> the type of the elements in this set
030 * @since 3.0
031 */
032public abstract class AbstractSetDecorator<E> extends AbstractCollectionDecorator<E> implements
033        Set<E> {
034
035    /** Serialization version */
036    private static final long serialVersionUID = -4678668309576958546L;
037
038    /**
039     * Constructor only used in deserialization, do not use otherwise.
040     * @since 3.1
041     */
042    protected AbstractSetDecorator() {
043        super();
044    }
045
046    /**
047     * Constructor that wraps (not copies).
048     *
049     * @param set  the set to decorate, must not be null
050     * @throws NullPointerException if set is null
051     */
052    protected AbstractSetDecorator(final Set<E> set) {
053        super(set);
054    }
055
056    /**
057     * Gets the set being decorated.
058     *
059     * @return the decorated set
060     */
061    @Override
062    protected Set<E> decorated() {
063        return (Set<E>) super.decorated();
064    }
065
066    @Override
067    public boolean equals(final Object object) {
068        return object == this || decorated().equals(object);
069    }
070
071    @Override
072    public int hashCode() {
073        return decorated().hashCode();
074    }
075
076}