Refactoring: Less Code, Less Problems (Part 1)

Video of this talk: https://www.youtube.com/watch?v=PjHZFTbg6gg

John talks about guidelines and code smells for improving object API design. He takes an existing class and demonstrates refactoring it to a leaner more focused version of its previous self. Most importantly, what questions to ask yourself as you're writing new classes.

Pass 1 (and a future Part 2) will approach refactoring a class from the outside as opposed to the inside. We discuss topics like breaking apart bigger classes to make smaller classes that do one thing, programming without getters and setters, consistent entry/return points, and guidelines for object instantiation. This talk focuses less on in-function refactoring and more on API-level refactoring.

Transcript

1. Less Code, Less Problems Pass 1(of 2) April 2, 2014
 Kansas City PHP User Group Slides: http://johnkary.net/talks John Kary Code Slinger, Build Breaker @johnkary
2. 0 Survey
 the land
3. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function setBucketIds($bucketIds){...}
 
 public function setBallIds($ballIds){...}
 
 public function setMinBallsPerBucket($count){...}
 
 public function setMinBucketsPerBall($count){...}
 
 public function run(){...}
 
 public function getResults(){...}
 
 public function getResultsByBall(){...}
 
 public function getMinBucketsPerBall(){...}
 
 public function getMinBallsPerBucket(){...}
 
 public function getBallPoolSize(){...}
 
 public function getStatusMessage(){...}
 
 public function createBallIdPool(){...}
 
 public function checkBallIdForBucketId($ballId, $bucketId){...}
 } CLASS
4. TEST
5. TEST
6. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $bucketIds;
 private $ballIds;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->bucketIds = array('a');
 $this->ballIds = array('200');
 
 $results = $this->runDistribution();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 
 // ...
 
 private function runDistribution() {
 $this->dist->setBucketIds($this->bucketIds);
 $this->dist->setBallIds($this->ballIds);
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall);
 
 $this->dist->run();
 
 return $this->dist->getResults();
 }
 } TEST
7. 1 Masking our PAIN
8. 1 DRY !== Better
9. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $bucketIds;
 private $ballIds;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->bucketIds = array('a');
 $this->ballIds = array('200');
 
 $results = $this->runDistribution();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 
 // ...
 
 private function runDistribution() {
 $this->dist->setBucketIds($this->bucketIds);
 $this->dist->setBallIds($this->ballIds);
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall);
 
 $this->dist->run();
 
 return $this->dist->getResults();
 }
 } TEST
10. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $bucketIds;
 private $ballIds;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->bucketIds = array('a');
 $this->ballIds = array('200');
 
 $this->dist->setBucketIds($this->bucketIds);
 $this->dist->setBallIds($this->ballIds);
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
11. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $bucketIds;
 private $ballIds;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->bucketIds = array('a');
 $this->ballIds = array('200');
 
 $this->dist->setBucketIds($this->bucketIds);
 $this->dist->setBallIds($this->ballIds);
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
12. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $bucketIds;
 private $ballIds;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->bucketIds = array('a');
 $this->ballIds = array('200');
 
 $this->dist->setBucketIds($this->bucketIds);
 $this->dist->setBallIds($this->ballIds);
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
13. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $bucketIds;
 private $ballIds;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->bucketIds = array('a');
 $this->ballIds = array('200');
 
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
14. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $bucketIds;
 private $ballIds;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->bucketIds = array('a');
 $this->ballIds = array('200');
 
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
15. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $bucketIds;
 private $ballIds;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
16. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
17. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
18. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->setMinBallsPerBucket($this->minBallsPerBucket);
 $this->dist->setMinBucketsPerBall($this->minBucketsPerBall); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
19. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->setMinBallsPerBucket(0);
 $this->dist->setMinBucketsPerBall(0); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
20. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->setMinBallsPerBucket(0);
 $this->dist->setMinBucketsPerBall(0); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
21. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0; ! // ... } CLASS
22. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->setMinBallsPerBucket(0);
 $this->dist->setMinBucketsPerBall(0); ! $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
23. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
24. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
25. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 $this->dist->run();
 
 $results = $this->dist->getResults();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
26. use KCPHPUG\BucketBallDistribution;
 
 class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /** @var BucketBallDistribution */
 private $dist;
 
 protected function setUp() {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeOneBucketToOneApp() {
 $this->dist->setBucketIds(array('a'));
 $this->dist->setBallIds(array('200'));
 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('200'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
28. 2Single Responsibility Principle
29. 2 A class should have
 one
 and only one
 reason to change
30. 2(I added the next part)
31. 2 and when it does change
 you should try to
 preserve
 its public API
32. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function setBucketIds($bucketIds){...}
 
 public function setBallIds($ballIds){...}
 
 public function setMinBallsPerBucket($count){...}
 
 public function setMinBucketsPerBall($count){...}
 
 public function run(){...}
 
 public function getResults(){...}
 
 public function getResultsByBall(){...}
 
 public function getMinBucketsPerBall(){...}
 
 public function getMinBallsPerBucket(){...}
 
 public function getBallPoolSize(){...}
 
 public function getStatusMessage(){...}
 
 public function createBallIdPool(){...}
 
 public function checkBallIdForBucketId($ballId, $bucketId){...}
 } CLASS
33. Smell! ! Too many public methods make it unclear how a class is supposed to be used
34. Public Methods
 communicate how a class can WILL BE used
35. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function setBucketIds($bucketIds){...}
 
 public function setBallIds($ballIds){...}
 
 public function setMinBallsPerBucket($count){...}
 
 public function setMinBucketsPerBall($count){...}
 
 public function run(){...}
 
 public function getResults(){...}
 
 public function getResultsByBall(){...}
 
 public function getMinBucketsPerBall(){...}
 
 public function getMinBallsPerBucket(){...}
 
 public function getBallPoolSize(){...}
 
 public function getStatusMessage(){...}
 
 public function createBallIdPool(){...}
 
 public function checkBallIdForBucketId($ballId, $bucketId){...}
 } CLASS
36. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Inform runtime about various state
 public function createBallIdPool()
 public function getBallPoolSize()
 public function checkBallIdForBucketId($ballId, $bucketId)
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
37. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Inform runtime about various state
 public function createBallIdPool()
 public function getBallPoolSize()
 public function checkBallIdForBucketId($ballId, $bucketId)
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
38. Find methods only used internally
 and hide them
39. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Inform runtime about various state
 public function createBallIdPool()
 public function getBallPoolSize()
 public function checkBallIdForBucketId($ballId, $bucketId)
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
40. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Inform runtime about various state
 public function createBallIdPool()
 public function getBallPoolSize()
 public function checkBallIdForBucketId($ballId, $bucketId)
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
41. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Inform runtime about various state
 private function createBallIdPool()
 private function getBallPoolSize()
 private function checkBallIdForBucketId($ballId, $bucketId)
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
42. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
43. Smell! ! When an object's public methods must be invoked
 in a specific order to properly use it
44. Object Instantiation Rules
45. An object should be ! ready to use and impossible to misuse! ! after it has been instantiated Object Instantiation Rules
46. An object should be ! ready to use and impossible to misuse! ! after it has been instantiated Object Instantiation Rules Enforce required values in the constructor
47. class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function setUp()
 {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array('201','202','203','204','205','206','207','208' $this->dist->setMinBallsPerBucket(1);
 $this->dist->setMinBucketsPerBall(3);
 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
48. class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function setUp()
 {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array('201','202','203','204','205','206','207','208' $this->dist->setMinBallsPerBucket(1);
 $this->dist->setMinBucketsPerBall(3);
 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
49. class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function setUp()
 {
 $this->dist = new BucketBallDistribution();
 }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array('201','202','203','204','205','206','207','208' $this->dist->setMinBallsPerBucket(1);
 $this->dist->setMinBucketsPerBall(3);
 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }
 } TEST
50. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array(‘201','202','203','204','205','206','207','208' $this->dist->setMinBallsPerBucket(1);
 $this->dist->setMinBucketsPerBall(3);
 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }
 }
51. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->build(3, 1);
 
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array(‘201','202','203','204','205','206','207','208' $this->dist->setMinBallsPerBucket(1);
 $this->dist->setMinBucketsPerBall(3);
 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }

52. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->build(3, 1);
 
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array(‘201','202','203','204','205','206','207','208' $this->dist->setMinBallsPerBucket(1);
 $this->dist->setMinBucketsPerBall(3);
 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }

53. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->build(3, 1);
 
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array(‘201','202','203','204','205','206','207','208' $this->dist->setMinBallsPerBucket(1);
 $this->dist->setMinBucketsPerBall(3);
 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }

54. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->build(3, 1);
 
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array(‘201','202','203','204','205','206','207','208' 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }
 }
55. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
56. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
57. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 } ! // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 CLASS
58. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 } ! // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 CLASS
59. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 } ! // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 CLASS
60. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 } ! // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 CLASS
61. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 } ! // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 CLASS
62. An object’s configuration should not change after instantiation API Design Principles
63. An object’s configuration should not change after instantiation If you need a different configuration create another instance API Design Principles
64. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 } ! // Set Configuration
 public function setMinBucketsPerBall($count)
 public function setMinBallsPerBucket($count)
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 CLASS
65. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 } ! // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall() ! // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
67. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 } ! // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
68. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 } ! // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
69. Do not expose getters for values you don’t use yset Do not expose getters for configuration API Design Principles
70. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 }
 
 // Get Configuration (but based on runtime data?)
 public function getMinBallsPerBucket()
 public function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
71. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 }
 
 // Get Configuration (but based on runtime data?)
 private function getMinBallsPerBucket()
 private function getMinBucketsPerBall()
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
72. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 // Set Configuration
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0) $this->minBucketsPerBall = $minBucketsPerBall; $this->minBallsPerBucket = $minBallsPerBucket;
 }
 
 // Set runtime data
 public function setBucketIds($bucketIds)
 public function setBallIds($ballIds)
 
 // Main runtime algorithm
 public function run()
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage()
 }
 CLASS
74. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->build(3, 1);
 
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array(‘201','202','203','204','205','206','207','208' 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }
 }
75. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->build(3, 1);
 
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array(‘201','202','203','204','205','206','207','208' 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }
 }
76. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! public function setBucketIds(array $bucketIds) {
 $this->bucketIds = $bucketIds;
 } ! public function setBallIds(array $ballIds) {
 $this->ballIds = $ballIds;
 }
 
 public function run() {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($this->bucketIds, $this->ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
77. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! public function setBucketIds(array $bucketIds) {
 $this->bucketIds = $bucketIds;
 } ! public function setBallIds(array $ballIds) {
 $this->ballIds = $ballIds;
 }
 
 public function run() {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($this->bucketIds, $this->ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
78. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! public function setBucketIds(array $bucketIds) {
 $this->bucketIds = $bucketIds;
 } ! public function setBallIds(array $ballIds) {
 $this->ballIds = $ballIds;
 }
 
 public function run() {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($this->bucketIds, $this->ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
79. Class and Methods Principles
80. Class and Methods Principles STATELESS Do not store data during execution
81. Class and Methods Principles STATELESS Do not store data during execution DETERMINISTIC Given the same input, the return value is identical
82. Class and Methods Principles STATELESS Do not store data during execution IDEMPOTENT Given the same input, the state of the system is identical when the method completes DETERMINISTIC Given the same input, the return value is identical
83. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->build(3, 1);
 
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array(‘201','202','203','204','205','206','207','208' 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }
 }
84. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3()
 {
 $this->build(3, 1);
 
 $this->dist->setBucketIds(array('a','b','c','d'));
 $this->dist->setBallIds(array(‘201','202','203','204','205','206','207','208' 
 $results = $this->dist->run();
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 }
 }
85. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3() {
 $this->build(3, 1);
 
 $bucketIds = array('a', 'b', 'c', 'd');
 $ballIds = array('201', '202', '203', '204', '205', '206', '207', '208', '209 
 $results = $this->dist->run($bucketIds, $ballIds);
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 } }
86. TEST class BucketBallDistributionTest extends \PHPUnit_Framework_TestCase
 {
 /**
 * @var BucketBallDistribution
 */
 private $dist;
 
 protected function build($minBucketsPerBall = 0, $minBallsPerBucket = 0)
 {
 $this->dist = new BucketBallDistribution($minBucketsPerBall, $minBallsPerBuck }
 
 public function testDistributeManyBucketToManyAppsLimit3() {
 $this->build(3, 1);
 
 $bucketIds = array('a', 'b', 'c', 'd');
 $ballIds = array('201', '202', '203', '204', '205', '206', '207', '208', '209 
 $results = $this->dist->run($bucketIds, $ballIds);
 $expected = array(
 'a' => array('201','205','209','203','207','204','208'),
 'b' => array('202','206','210','204','208','201','205','209'),
 'c' => array('203','207','201','205','209','202','206','210'),
 'd' => array('204','208','202','206','210','203','207'),
 );
 
 $this->assertEquals($expected, $results);
 } }
87. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! public function setBucketIds(array $bucketIds) {
 $this->bucketIds = $bucketIds;
 } ! public function setBallIds(array $ballIds) {
 $this->ballIds = $ballIds;
 }
 
 public function run() {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($this->bucketIds, $this->ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
88. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! public function setBucketIds(array $bucketIds) {
 $this->bucketIds = $bucketIds;
 } ! public function setBallIds(array $ballIds) {
 $this->ballIds = $ballIds;
 }
 
 public function run() {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($this->bucketIds, $this->ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
89. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! public function setBucketIds(array $bucketIds) {
 $this->bucketIds = $bucketIds;
 } ! public function setBallIds(array $ballIds) {
 $this->ballIds = $ballIds;
 }
 
 public function run(array $bucketIds, array $ballIds) {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($this->bucketIds, $this->ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
90. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! public function setBucketIds(array $bucketIds) {
 $this->bucketIds = $bucketIds;
 } ! public function setBallIds(array $ballIds) {
 $this->ballIds = $ballIds;
 }
 
 public function run(array $bucketIds, array $ballIds) {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($this->bucketIds, $this->ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
91. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! public function setBucketIds(array $bucketIds) {
 $this->bucketIds = $bucketIds;
 } ! public function setBallIds(array $ballIds) {
 $this->ballIds = $ballIds;
 }
 
 public function run(array $bucketIds, array $ballIds) {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($bucketIds, $ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
92. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! public function setBucketIds(array $bucketIds) {
 $this->bucketIds = $bucketIds;
 } ! public function setBallIds(array $ballIds) {
 $this->ballIds = $ballIds;
 }
 
 public function run(array $bucketIds, array $ballIds) {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($bucketIds, $ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
93. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall; private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! ! ! ! ! ! ! 
 
 public function run(array $bucketIds, array $ballIds) {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($bucketIds, $ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
94. class BucketBallDistribution
 {
 private $minBallsPerBucket;
 private $minBucketsPerBall; private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! ! ! ! ! ! ! 
 
 public function run(array $bucketIds, array $ballIds) {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($bucketIds, $ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
95. class BucketBallDistribution
 {
 private $minBallsPerBucket;
 private $minBucketsPerBall; private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! ! ! ! ! ! ! 
 
 public function run(array $bucketIds, array $ballIds) {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($bucketIds, $ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
96. class BucketBallDistribution
 {
 private $minBallsPerBucket;
 private $minBucketsPerBall; private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! ! ! ! ! ! ! 
 
 public function run(array $bucketIds, array $ballIds) {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($bucketIds, $ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
97. class BucketBallDistribution
 {
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){} ! ! ! ! ! ! ! 
 
 public function run(array $bucketIds, array $ballIds) {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($bucketIds, $ballIds); while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
99. class BucketBallDistribution
 {
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){ 
 // Main runtime algorithm
 public function run(array $bucketIds, array $ballIds)
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage(array $bucketIds, array $ballIds)
 }
 CLASS
100. class BucketBallDistribution
 {
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){ 
 // Main runtime algorithm
 public function run(array $bucketIds, array $ballIds)
 
 // Get results after runtime
 public function getResults()
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage(array $bucketIds, array $ballIds)
 }
 CLASS
101. class BucketBallDistribution
 {
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 
 public function getResults() {
 return $this->results;
 } ! public function run() {
 $this->results = array();
 $this->resultsByBall = array();
 
 $ballPool = $this->createBallIdPool($this->bucketIds, $this->ballI while ($ballPool ...) {
 // ...
 $this->results[$bucketId][] = $ballId;
 // ...
 }
 
 return $this->results;
 } } CLASS
102. class BucketBallDistribution
 {
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall = 0, $minBallsPerBucket = 0){ 
 // Main runtime algorithm
 public function run(array $bucketIds, array $ballIds)
 
 // Get results after runtime
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage(array $bucketIds, array $ballIds)
 }
 CLASS
104. ass BucketBallDistribution
 private $bucketIds = array();
 private $ballIds = array();
 private $minBallsPerBucket = 0;
 private $minBucketsPerBall = 0;
 private $ballPool = array();
 private $results = array();
 private $resultsByBall = array();
 public function setBucketIds($bucketIds){...}
 public function setBallIds($ballIds){...}
 public function setMinBallsPerBucket($count){...}
 public function setMinBucketsPerBall($count){...}
 public function run(){...}
 public function getResults(){...}
 public function getResultsByBall(){...}
 public function getMinBucketsPerBall(){...}
 public function getMinBallsPerBucket(){...}
 public function getBallPoolSize(){...}
 public function getStatusMessage(){...}
 public function createBallIdPool(){...}
 public function checkBallIdForBucketId($ballId, $bucketId){...}
 class BucketBallDistribution
 {
 private $minBallsPerBucket;
 private $minBucketsPerBall;
 private $results = array();
 private $resultsByBall = array();
 
 public function __construct($minBucketsPerBall 
 // Main runtime algorithm
 public function run(array $bucketIds, array $ba 
 // Get results after runtime
 public function getResultsByBall()
 
 // Text describing results
 public function getStatusMessage(array $bucketI 

105. Further Learning Refactoring: Improving the Design of Existing Code
 Martin Fowler, 2000 http://refactoring.com Less: The Path to Better Design
 Sandi Metz (GoRuCo 2011) http://vimeo.com/26330100 Therapeutic Refactoring
 Katrina Owen (2012) http://www.youtube.com/watch?v=J4dlF0kcThQ
106. Questions John Kary Code Slinger, Build Breaker @johnkary http://johnkary.net/talks