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.generator; 018 019import org.apache.commons.functor.Predicate; 020import org.apache.commons.functor.Procedure; 021import org.apache.commons.functor.core.composite.ConditionalProcedure; 022import org.apache.commons.lang3.Validate; 023 024/** 025 * Generator that filters another Generator by only passing through those elements 026 * that are matched by a specified Predicate. 027 * 028 * @param <E> the type of elements held in this generator. 029 * @version $Revision: 1522355 $ $Date: 2013-09-12 06:29:46 +0200 (Do, 12 Sep 2013) $ 030 */ 031public class FilteredGenerator<E> extends BaseGenerator<E> { 032 033 /** 034 * A generator can wrap another generator. 035 * */ 036 private Generator<? extends E> wrappedGenerator; 037 038 /** 039 * The predicate used to filter. 040 */ 041 private final Predicate<? super E> pred; 042 043 /** 044 * Create a new FilteredGenerator. 045 * @param wrapped Generator to wrap 046 * @param pred filtering Predicate 047 */ 048 public FilteredGenerator(Generator<? extends E> wrapped, Predicate<? super E> pred) { 049 this.wrappedGenerator = Validate.notNull(wrapped, "Generator argument was null"); 050 this.pred = Validate.notNull(pred, "Predicate argument was null"); 051 } 052 053 /** 054 * {@inheritDoc} 055 */ 056 public void run(Procedure<? super E> proc) { 057 getWrappedGenerator().run(new ConditionalProcedure<E>(pred, proc)); 058 } 059 060 /** 061 * Get the generator that is being wrapped. 062 * @return Generator 063 */ 064 protected Generator<? extends E> getWrappedGenerator() { 065 return this.wrappedGenerator; 066 } 067 068 /** 069 * {@inheritDoc} 070 */ 071 @Override 072 public boolean equals(Object obj) { 073 if (obj == this) { 074 return true; 075 } 076 if (!(obj instanceof FilteredGenerator<?>)) { 077 return false; 078 } 079 FilteredGenerator<?> other = (FilteredGenerator<?>) obj; 080 return other.getWrappedGenerator().equals(getWrappedGenerator()) && other.pred.equals(pred); 081 } 082 083 /** 084 * {@inheritDoc} 085 */ 086 @Override 087 public int hashCode() { 088 int result = "FilteredGenerator".hashCode(); 089 result <<= 2; 090 Generator<?> gen = getWrappedGenerator(); 091 result ^= gen.hashCode(); 092 result <<= 2; 093 result ^= pred.hashCode(); 094 return result; 095 } 096}