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.iterators;
018
019import java.util.Iterator;
020
021import org.apache.commons.collections4.functors.UniquePredicate;
022
023/**
024 * A FilterIterator which only returns "unique" Objects.  Internally,
025 * the Iterator maintains a Set of objects it has already encountered,
026 * and duplicate Objects are skipped.
027 *
028 * @param <E> the type of elements returned by this iterator.
029 * @since 2.1
030 */
031public class UniqueFilterIterator<E> extends FilterIterator<E> {
032
033    /**
034     *  Constructs a new {@code UniqueFilterIterator}.
035     *
036     *  @param iterator  the iterator to use
037     */
038    public UniqueFilterIterator(final Iterator<? extends E> iterator) {
039        super(iterator, UniquePredicate.uniquePredicate());
040    }
041
042}