Windbag MapReduce Application

Motivation

A simple Mapper and two simple ClassicReducers reinforce our understanding of how pieces of the MapReduce puzzle can be reused. Further, we will reduce the value type of List<Boolean> to both an Integer and a Double in separate Reducers.

Background

A windbag is an exhaustively talkative person. Act I Scene 3 of Hamlet has a famous example.

In this assignment we will try to determine who is the biggest windbag in a particular play with Hamlet and The Importance of Being Earnest serving as two pieces of data.

Code To Implement

WindbagMapper

class:	WindbagMapper.java
methods:	windbagLinePredicate map
package:	mapreduce.apps.windbag.studio
source folder:	student/src/main/java

constructor and instance variable

method: public WindbagMapper(IntPredicate windbagLinePredicate) (sequential implementation only)

Hang onto the value of the windbagLinePredicate parameter as an instance variable for later use.

windbagLinePredicate

This method exists largely as a reminder to use the windbagLinePredicate passed to the constructor.

map

Note: the WindBagMapper is constructed with an IntPredicate. This IntPredicate's test method should be invoked to determine if a PlayLine's word count qualifies it as a windbag line. You can investigate the PlayLine class to see what information it contains.

method: public List<Map.Entry<PlayRole, Boolean>> map(PlayLine item) (sequential implementation only)

TrueCountClassicReducer

This Collector reduces to the number of emitted trues.

For example, if a total of eight (8) values were emitted for a particular key and three (3) of them were true:

[false, true, false, false, true, true, false, false]

then the reduced value would be 3

class:	TrueCountClassicReducer.java
methods:	reduce
package:	mapreduce.apps.windbag.exercise
source folder:	student/src/main/java

method: public Integer reduce(List<Boolean> container) (sequential implementation only)

Warning:This class inherits from ClassicReducer. Be sure to have completed that studio first.

TruePortionClassicReducer

This Collector reduces to the portion of emitted trues.

For example, if a total of eight (8) values were emitted for a particular key and three (3) of them were true:

[false, true, false, false, true, true, false, false]

then the reduced value would be 0.375

class:	TruePortionClassicReducer.java
methods:	reduce
package:	mapreduce.apps.windbag.exercise
source folder:	student/src/main/java

method: public Double reduce(List<Boolean> container) (sequential implementation only)

Warning:This class inherits from ClassicReducer. Be sure to have completed that studio first.

Client

class:	WindbagApp.java	CLIENT
package:	mapreduce.apps.windbag.client
source folder:	student/src//java

HAMLET

COUNT =========================== HAMLET: 27 KING: 14 POLONIUS: 7 HORATIO: 5 OPHELIA: 2 GHOST: 2 FIRST PLAYER: 2 LAERTES: 1 ROSENCRANTZ: 1 VOLTEMAND: 1 PLAYER KING: 1 GENTLEMAN: 1 PLAYER QUEEN: 1 QUEEN: 1 PORTION =========================== VOLTEMAND: 1.000000 GENTLEMAN: 0.333333 PLAYER KING: 0.250000 FIRST PLAYER: 0.250000 PLAYER QUEEN: 0.200000 GHOST: 0.142857 KING: 0.137255 POLONIUS: 0.081395 HAMLET: 0.075419 HORATIO: 0.046729 OPHELIA: 0.034483 ROSENCRANTZ: 0.022222 LAERTES: 0.016129 QUEEN: 0.014493

THE_IMPORTANCE_OF_BEING_EARNEST
COUNT =========================== LADY BRACKNELL: 7 JACK: 3 ALGERNON: 2 GWENDOLEN: 2 MISS PRISM: 1 CHASUBLE: 1 PORTION =========================== LADY BRACKNELL: 0.083333 MISS PRISM: 0.024390 CHASUBLE: 0.023810 GWENDOLEN: 0.019802 JACK: 0.013825 ALGERNON: 0.009950

Testing Your Solution

class:	_WindbagTestSuite.java
package:	mapreduce.apps.windbag.exercise
source folder:	testing/src/test/java

Pledge, Acknowledgments, Citations

file:

mapreduce-windbag-app-pledge-acknowledgments-citations.txt

More info about the Honor Pledge