pu.RedLib

Class MapUnion<K,T>

java.lang.Object

pu.RedLib.MapUnion<K,T>

All Implemented Interfaces:

Reduction<java.util.Map<K,T>>

public class MapUnion<K,T>
extends java.lang.Object
implements Reduction<java.util.Map<K,T>>

This class reduces two Map objects into one by merging them into the first Map object. The process checks every key in the second Map object. For the keys that exist in the first Map object as well, the values will be merged according to programmer's specifications. If the first Map object does not contain the key already, then the key and its corresponding value will be added to the first Map object.

Since:

14/10/2014

Author:

Mostafa Mehrabi

Field Summary

Fields

Modifier and Type	Field and Description
protected Reduction<T>	reducer

Fields inherited from interface pu.RedLib.Reduction

ArrayCOMBINE, BooleanBITAND, BooleanBITOR, BooleanBITXOR, BooleanLOGAND, BooleanLOGOR, ByteBITAND, ByteBITOR, ByteBITXOR, ByteMAX, ByteMIN, ByteMINUS, ByteMULTI, ByteSUM, DoubleBITAND, DoubleBITOR, DoubleBITXOR, DoubleLOGAND, DoubleLOGOR, DoubleMAX, DoubleMIN, DoubleMINUS, DoubleMULTI, DoubleSUM, FloatMAX, FloatMIN, FloatMINUS, FloatMULTI, FloatSUM, IntegerBITAND, IntegerBITOR, IntegerBITXOR, IntegerLOGAND, IntegerLOGOR, IntegerMAX, IntegerMIN, IntegerMINUS, IntegerMULTI, IntegerSUM, LongBITAND, LongBITOR, LongBITXOR, LongLOGOR, LongMAX, LongMIN, LongMINUS, LongMULTI, LongSUM, ShortBITAND, ShortBITOR, ShortBITXOR, ShortMAX, ShortMIN, ShortMINUS, ShortMULTI, ShortSUM

Constructor Summary

Constructors

Constructor and Description
MapUnion(Reduction<T> reducer)

Method Summary

Modifier and Type	Method and Description
java.util.Map<K,T>	reduce(java.util.Map<K,T> first, java.util.Map<K,T> second) Specifies a reduction as defined by 2 elements into 1.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

reducer

protected Reduction<T> reducer

Constructor Detail

MapUnion

public MapUnion(Reduction<T> reducer)

Method Detail

reduce

public java.util.Map<K,T> reduce(java.util.Map<K,T> first,
                                 java.util.Map<K,T> second)

Description copied from interface: Reduction

Specifies a reduction as defined by 2 elements into 1. The reduction must obey the following 2 constraints:

• Associative: the order of evaluating the reduction makes no difference, and
• Commutative: the order of the thread-local values makes no difference.

Specified by:

reduce in interface Reduction<java.util.Map<K,T>>

Parameters:

first - The first element in the reduction.

second - The second element in the reduction.

Returns:

The result of reducing first with second.