1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.functor.core.algorithm; 18 19 import java.io.Serializable; 20 import java.util.Iterator; 21 22 import org.apache.commons.functor.BinaryProcedure; 23 import org.apache.commons.functor.UnaryPredicate; 24 import org.apache.commons.functor.core.composite.UnaryNot; 25 26 /** 27 * Retain elements in left Iterator that match right UnaryPredicate. 28 * 29 * @version $Revision: 1166328 $ $Date: 2011-09-07 21:32:26 +0200 (Wed, 07 Sep 2011) $ 30 */ 31 public final class RetainMatching<T> 32 implements BinaryProcedure<Iterator<? extends T>, UnaryPredicate<? super T>>, Serializable { 33 /** 34 * serialVersionUID declaration. 35 */ 36 private static final long serialVersionUID = 6760018011875465469L; 37 38 private static final RetainMatching<Object> INSTANCE = new RetainMatching<Object>(); 39 40 private RemoveMatching<T> removeMatching = new RemoveMatching<T>(); 41 42 /** 43 * {@inheritDoc} 44 * @param left {@link Iterator} 45 * @param right {@link UnaryPredicate} 46 */ 47 public void run(Iterator<? extends T> left, UnaryPredicate<? super T> right) { 48 removeMatching.run(left, UnaryNot.not(right)); 49 } 50 51 /** 52 * {@inheritDoc} 53 */ 54 public boolean equals(Object obj) { 55 return obj == this || obj != null && obj.getClass().equals(getClass()); 56 } 57 58 /** 59 * {@inheritDoc} 60 */ 61 public int hashCode() { 62 return System.identityHashCode(INSTANCE); 63 } 64 65 /** 66 * Get a static {@link RetainMatching} instance. 67 * @return {@link RetainMatching} 68 */ 69 public static RetainMatching<Object> instance() { 70 return INSTANCE; 71 } 72 }