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.functor.core.algorithm;
018
019import java.util.Iterator;
020
021import org.apache.commons.functor.BinaryProcedure;
022import org.apache.commons.functor.Predicate;
023
024/**
025 * Remove elements from left Iterator that match right Predicate.
026 *
027 * @param <T> the procedure argument type.
028 * @version $Revision: 1537906 $ $Date: 2013-11-01 12:47:33 +0100 (Fr, 01 Nov 2013) $
029 */
030public final class RemoveMatching<T>
031    implements BinaryProcedure<Iterator<? extends T>, Predicate<? super T>> {
032    /**
033     * A static {@link RemoveMatching} instance reference.
034     */
035    private static final RemoveMatching<Object> INSTANCE = new RemoveMatching<Object>();
036
037    /**
038     * {@inheritDoc}
039     * @param left {@link Iterator}
040     * @param right {@link Predicate}
041     */
042    public void run(Iterator<? extends T> left, Predicate<? super T> right) {
043        while (left.hasNext()) {
044            if (right.test(left.next())) {
045                left.remove();
046            }
047        }
048    }
049
050    /**
051     * {@inheritDoc}
052     */
053    @Override
054    public boolean equals(Object obj) {
055        return obj == this || obj != null && obj.getClass().equals(getClass());
056    }
057
058    /**
059     * {@inheritDoc}
060     */
061    @Override
062    public int hashCode() {
063        return System.identityHashCode(INSTANCE);
064    }
065
066    /**
067     * {@inheritDoc}
068     */
069    @Override
070    public String toString() {
071        return "RemoveMatching";
072    }
073
074    /**
075     * Get a static {@link RemoveMatching} instance.
076     * @return {@link RemoveMatching}
077     */
078    public static RemoveMatching<Object> instance() {
079        return INSTANCE;
080    }
081
082}