001 /* 002 * Copyright (c) 2007-2014 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 */ 020 021 package cascading.pipe.joiner; 022 023 import java.beans.ConstructorProperties; 024 import java.util.Arrays; 025 import java.util.Iterator; 026 027 import cascading.tuple.Fields; 028 import cascading.tuple.Tuple; 029 030 /** 031 * Class MixedJoin will return an {@link java.util.Iterator} that will iterate over a given 032 * {@link Joiner} and return tuples that represent a join as defined by the given boolean array. 033 * <p/> 034 * So if joining three streams, {@code boolean []{true,false,false}} will result in a 'inner', 'outer', 'outer' join. 035 * <p/> 036 * Joins perform based on the equality of the join keys. In the case of null values, Java treats two 037 * null values as equivalent. SQL does not treat null values as equal. To produce SQL like results in a given 038 * join, a new {@link java.util.Comparator} will need to be used on the joined values to prevent null from 039 * equaling null. As a convenience, see the {@link cascading.util.NullNotEquivalentComparator} class. 040 */ 041 public class MixedJoin extends BaseJoiner 042 { 043 /** Field INNER */ 044 public static boolean INNER = true; 045 /** Field OUTER */ 046 public static boolean OUTER = false; 047 048 final boolean[] asInner; 049 050 /** 051 * Constructor MixedJoin creates a new MixedJoin instance. 052 * 053 * @param asInner of type boolean[] 054 */ 055 @ConstructorProperties({"asInner"}) 056 public MixedJoin( boolean[] asInner ) 057 { 058 this.asInner = Arrays.copyOf( asInner, asInner.length ); 059 } 060 061 @ConstructorProperties({"fieldDeclaration","asInner"}) 062 public MixedJoin( Fields fieldDeclaration, boolean[] asInner ) 063 { 064 super( fieldDeclaration ); 065 this.asInner = asInner; 066 } 067 068 /** @see Joiner#numJoins() */ 069 public int numJoins() 070 { 071 return asInner.length - 1; 072 } 073 074 public Iterator<Tuple> getIterator( JoinerClosure closure ) 075 { 076 return new JoinIterator( closure ); 077 } 078 079 public class JoinIterator extends OuterJoin.JoinIterator 080 { 081 public JoinIterator( JoinerClosure closure ) 082 { 083 super( closure ); 084 } 085 086 @Override 087 protected boolean isOuter( int i ) 088 { 089 return !asInner[ i ] && super.isOuter( i ); 090 } 091 } 092 }