001/* 002 * Copyright (c) 2007-2015 Concurrent, Inc. All Rights Reserved. 003 * 004 * Project and contact information: http://www.cascading.org/ 005 * 006 * This file is part of the Cascading project. 007 * 008 * Licensed under the Apache License, Version 2.0 (the "License"); 009 * you may not use this file except in compliance with the License. 010 * You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, software 015 * distributed under the License is distributed on an "AS IS" BASIS, 016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 017 * See the License for the specific language governing permissions and 018 * limitations under the License. 019 */ 020 021package cascading.operation.aggregator; 022 023import java.beans.ConstructorProperties; 024import java.util.Collection; 025import java.util.Collections; 026import java.util.HashSet; 027 028import cascading.flow.FlowProcess; 029import cascading.operation.Aggregator; 030import cascading.operation.AggregatorCall; 031import cascading.operation.BaseOperation; 032import cascading.operation.OperationCall; 033import cascading.tuple.Fields; 034import cascading.tuple.Tuple; 035import cascading.tuple.TupleEntry; 036 037/** Class ExtentBase is the base class for First and Last. */ 038public abstract class ExtentBase extends BaseOperation<Tuple[]> implements Aggregator<Tuple[]> 039 { 040 /** Field ignoreTuples */ 041 private final Collection<Tuple> ignoreTuples; 042 043 @ConstructorProperties({"fieldDeclaration"}) 044 protected ExtentBase( Fields fieldDeclaration ) 045 { 046 super( fieldDeclaration ); 047 this.ignoreTuples = null; 048 } 049 050 @ConstructorProperties({"numArgs", "fieldDeclaration"}) 051 protected ExtentBase( int numArgs, Fields fieldDeclaration ) 052 { 053 super( numArgs, fieldDeclaration ); 054 ignoreTuples = null; 055 } 056 057 @ConstructorProperties({"fieldDeclaration", "ignoreTuples"}) 058 protected ExtentBase( Fields fieldDeclaration, Tuple... ignoreTuples ) 059 { 060 super( fieldDeclaration ); 061 this.ignoreTuples = new HashSet<Tuple>(); 062 Collections.addAll( this.ignoreTuples, ignoreTuples ); 063 } 064 065 public Collection<Tuple> getIgnoreTuples() 066 { 067 return Collections.unmodifiableCollection( ignoreTuples ); 068 } 069 070 @Override 071 public void prepare( FlowProcess flowProcess, OperationCall<Tuple[]> operationCall ) 072 { 073 operationCall.setContext( new Tuple[ 1 ] ); 074 } 075 076 @Override 077 public void start( FlowProcess flowProcess, AggregatorCall<Tuple[]> aggregatorCall ) 078 { 079 aggregatorCall.getContext()[ 0 ] = null; 080 } 081 082 @Override 083 public void aggregate( FlowProcess flowProcess, AggregatorCall<Tuple[]> aggregatorCall ) 084 { 085 if( ignoreTuples != null && ignoreTuples.contains( aggregatorCall.getArguments().getTuple() ) ) 086 return; 087 088 performOperation( aggregatorCall.getContext(), aggregatorCall.getArguments() ); 089 } 090 091 protected abstract void performOperation( Tuple[] context, TupleEntry entry ); 092 093 @Override 094 public void complete( FlowProcess flowProcess, AggregatorCall<Tuple[]> aggregatorCall ) 095 { 096 if( aggregatorCall.getContext()[ 0 ] != null ) 097 aggregatorCall.getOutputCollector().add( getResult( aggregatorCall ) ); 098 } 099 100 protected Tuple getResult( AggregatorCall<Tuple[]> aggregatorCall ) 101 { 102 return aggregatorCall.getContext()[ 0 ]; 103 } 104 105 @Override 106 public boolean equals( Object object ) 107 { 108 if( this == object ) 109 return true; 110 if( !( object instanceof ExtentBase ) ) 111 return false; 112 if( !super.equals( object ) ) 113 return false; 114 115 ExtentBase that = (ExtentBase) object; 116 117 if( ignoreTuples != null ? !ignoreTuples.equals( that.ignoreTuples ) : that.ignoreTuples != null ) 118 return false; 119 120 return true; 121 } 122 123 @Override 124 public int hashCode() 125 { 126 int result = super.hashCode(); 127 result = 31 * result + ( ignoreTuples != null ? ignoreTuples.hashCode() : 0 ); 128 return result; 129 } 130 }