/*

 * 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 org.apache.commons.collections4.set;

import java.util.Set;

import org.apache.commons.collections4.Predicate;

import org.apache.commons.collections4.collection.PredicatedCollection;

/**

 * Decorates another <code>Set</code> to validate that all additions

 * match a specified predicate.

 * <p>

 * This set exists to provide validation for the decorated set.

 * It is normally created to decorate an empty set.

 * If an object cannot be added to the set, an IllegalArgumentException is thrown.

 * </p>

 * <p>

 * One usage would be to ensure that no null entries are added to the set.

 * </p>

 * <pre>Set set = PredicatedSet.decorate(new HashSet(), NotNullPredicate.INSTANCE);</pre>

 * <p>

 * This class is Serializable from Commons Collections 3.1.

 * </p>

 *

 * @param <E> the type of the elements in this set

 * @since 3.0

 */

public class PredicatedSet<E> extends PredicatedCollection<E> implements Set<E> {

    /** Serialization version */

    private static final long serialVersionUID = -684521469108685117L;

    /**

     * Factory method to create a predicated (validating) set.

     * <p>

     * If there are any elements already in the set being decorated, they

     * are validated.

     *

     * @param <E> the element type

     * @param set  the set to decorate, must not be null

     * @param predicate  the predicate to use for validation, must not be null

     * @return a decorated set

     * @throws NullPointerException if set or predicate is null

     * @throws IllegalArgumentException if the set contains invalid elements

     * @since 4.0

     */

    public static <E> PredicatedSet<E> predicatedSet(final Set<E> set, final Predicate<? super E> predicate) {

        return new PredicatedSet<>(set, predicate);

    }

    //-----------------------------------------------------------------------

    /**

     * Constructor that wraps (not copies).

     * <p>

     * If there are any elements already in the set being decorated, they

     * are validated.

     *

     * @param set  the set to decorate, must not be null

     * @param predicate  the predicate to use for validation, must not be null

     * @throws NullPointerException if set or predicate is null

     * @throws IllegalArgumentException if the set contains invalid elements

     */

    protected PredicatedSet(final Set<E> set, final Predicate<? super E> predicate) {

        super(set, predicate);

    }

    /**

     * Gets the set being decorated.

     *

     * @return the decorated set

     */

    @Override

    protected Set<E> decorated() {

        return (Set<E>) super.decorated();

    }

    @Override

    public boolean equals(final Object object) {

        return object == this || decorated().equals(object);

    }

    @Override

    public int hashCode() {

        return decorated().hashCode();

    }

}