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     */
017    package org.apache.commons.functor.core.algorithm;
018    
019    import java.io.Serializable;
020    import java.util.Iterator;
021    
022    import org.apache.commons.functor.BinaryProcedure;
023    import org.apache.commons.functor.UnaryPredicate;
024    
025    /**
026     * Remove elements from left Iterator that match right UnaryPredicate.
027     *
028     * @version $Revision: 1166325 $ $Date: 2011-09-07 21:29:00 +0200 (Wed, 07 Sep 2011) $
029     */
030    public final class RemoveMatching<T>
031        implements BinaryProcedure<Iterator<? extends T>, UnaryPredicate<? super T>>, Serializable {
032        /**
033         * serialVersionUID declaration.
034         */
035        private static final long serialVersionUID = -8376577687898040683L;
036        private static final RemoveMatching<Object> INSTANCE = new RemoveMatching<Object>();
037    
038        /**
039         * {@inheritDoc}
040         * @param left {@link Iterator}
041         * @param right {@link UnaryPredicate}
042         */
043        public void run(Iterator<? extends T> left, UnaryPredicate<? super T> right) {
044            while (left.hasNext()) {
045                if (right.test(left.next())) {
046                    left.remove();
047                }
048            }
049        }
050    
051        /**
052         * {@inheritDoc}
053         */
054        public boolean equals(Object obj) {
055            return obj == this || obj != null && obj.getClass().equals(getClass());
056        }
057    
058        /**
059         * {@inheritDoc}
060         */
061        public int hashCode() {
062            return System.identityHashCode(INSTANCE);
063        }
064    
065        /**
066         * Get a static {@link RemoveMatching} instance.
067         * @return {@link RemoveMatching}
068         */
069        public static RemoveMatching<Object> instance() {
070            return INSTANCE;
071        }
072    
073    }