In this Course, Francesco Cirillo shows his solution.

This Course is available in several formats:

Course Content

This Challenge is organized in four parts.

PART 01 - Development of the Original Kata

Let's start with the analysis of the problem defined by the Kata.

• Introduction of the original Kata proposed by Bob Martin.
• Presentation of the User Stories, Scenarios and Requirements
• Definition of criteria to evaluate the effectiveness of software design.
• Development of Bob Martin's original Kata in Test-Driven Development (TDD), one scenario at a time.
• Assessment of the result achieved in terms of design. What abstractions emerged? Was the TDD effective?

PART 02 - Delivery of the Original Kata

Bowling Kata done!

• Development and delivery of Bob Martin's original Kata.
• The evolution of our design so far. Has TDD been effective? Why?
• Assessment of the design emerged one test at a time.

PART 03 - Development of New Requests

Embrace Change!

• Presentation of the new requests defined in the Open/Closed Principle Dojo by Matteo Vaccari and Antonio Carpentieri.
• Writing of the User Stories, Scenarios and Requirements related to the new requests.
• Development and delivery of the new User Stories.
• Assessment of the design emerged so far. How much did it cost to deliver those Stories? Had the current system helped us?

PART 04 - Let's Unleash our Imagination

Let's come up with new requests!

• Presentation of requests taken from the community "The Bowling Kata Challenge"
• Writing of the User Stories, Scenarios and Requirements related to the new requests.
• Development and delivery of the new User Stories.
• Assessment of the design emerged so far. How much did it cost to deliver those Stories? Were we able to reduce the cost of change in our Bowling Kata? Is our software design "simple"? How can we define "simple"?

About this Course

The Bowling Kata Challenge is a Course in which Francesco Cirillo, develops one or more features of an application that can calculate the score of a bowling match. Francesco demonstrates how he makes software design decisions, applies TDD, emergent design principles, his choices of one pattern over another, and his preferences of certain practices.

Objectives

As a result of this course, you will learn to:

The Story Behind this Challenge

Francesco Cirillo tells the story behind the Bowling Kata Anti-If Challenge.

"This Challenge was born out of a request from Damir, one of the participants in the Software Production You and Me Mentoring Programme. One day, he asked me: 'I would like to see how you would develop the Bowling Kata without IFs.'

I admit that I did not know of the Bowling Kata. This Kata is about developing an application that can calculate the score of a bowling match. Robert Martin provided a solution in 2005 to demonstrate how he applies TDD. Robert Martin's solution is considered by many as a 'procedural solution.' The result of applying the 'IF Strategy' several times to deal with new tests. I understand the reason for Damir's request.

	public int score() {
		int score = 0;
		int frameIndex = 0;
		for (int frame = 0; frame < 10; frame++) {
			int frameIndex = 0;
IF=>		if (isStrike(frameIndex)) {
			score += 10 + strikeBonus(frameIndex);
			frameIndex++;
IF=>		} else if (isSpare(frameIndex)) {
      				score += 10 + spareBonus(frameIndex);
					frameIndex += 2;
IF=>		} else {
					score += sumOfBallsInFrame(frameIndex);
					frameIndex += 2;
      		}
      	}
      	return score;
      }
      

	public int score() {
		int score = 0;
        int currentRoll = 0;
        int numFrames = isMartian() ? 12 : (isVenusian() ? 11: 10);
		for (int frame = 0; frame < numFrames; frame++) {
IF=>		if (callistoVariant() && isLastFrame(frame) {
        		while(isStrike(currentRoll, frame)) {
                	score += 10 + sumOfTwoRolls(currentRolls+1);
                    currentRoll++;
                }
IF=>		} else {
IF=>            if(isStrike(currentRoll)) {
                	score += 10 + sumOfTwoRolls(currentRolls + 1);
                    currentRoll++;
                }
            }
IF=>		} if (isSpare(currentRoll)) {
      			score += 10 + rolls[currentRolls+1];
				currentRoll += 2;
IF=>		} else if (isMartian() {
				score += sumOfThreeRolls(currentRolls);
				currentRoll += 3;
IF=>		} else {
				score = sumOfTwoRolls(currentRolls);
				currentRoll += 2;
			}
		}
      	return score;
      }
      
	public boolean isStrike(int currentRoll, int frame) {
IF=>	if (isVenusian()) {
			return rolls[currentRoll] == frame;
		}
		return rolls[currentRoll] == 10;
	}

About the Trainer

Francesco Cirillo

Francesco Cirillo has worked at the forefront of the software industry for more than 30 years. In a career spanning startups, corporations and freelance consulting, he has mentored thousands of professionals, developers, managers and software teams.

In the 1990s he worked as a Senior Consultant and Mentor for Sun Microsystem, expert in Software Architectures and Software Development Processes and Java and Object-Oriented Evangelist.

Francesco is one of the pioneers of Agile Methods. He started working on XP and TDD in 1999. He was chosen by Kent Beck to develop the XP community in Europe and as reviewer of the second edition of the book Extreme Programming Explained. In 2000 he created XPLabs, the first company in Europe to offer comprehensive services on XP: software development, training and consulting.

In 2007 he created the Anti-IF Campaign to raise awareness in the international community of software developers to apply good design principles to grow software in a sustainable way.

Since 2008 Francesco stopped actively working on Agile Methods and started to develop RRP, a new method of software development. In 2013 he created Cirillo Consulting based in Berlin to offer professional training and consulting on productivity and software development.

Francesco invented the Pomodoro® Technique, a renowned time-management method used by millions of people all over the world, while being a university student looking for a way to get more done in less time.

Read the Francesco Cirillo's complete profile.

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