    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 *      https://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} to provide additional behavior.
    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     *
    041     * @since 3.1
    042     */
    043    protected AbstractSetDecorator() {
    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}