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
   

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2. 0
   Survey

   the land
   

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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
   

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4. TEST
   

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5. TEST
   

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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
   

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7. 1
   Masking our
   PAIN
   

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8. 1
   DRY !== Better
   

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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
   

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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21. class BucketBallDistribution

    {

    private $bucketIds = array();

    private $ballIds = array();

    

    private $minBallsPerBucket = 0;

    private $minBucketsPerBall = 0;
    !
    // ...
    }
    CLASS
    

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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
    

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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
    

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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
    

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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
    

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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
    

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27. View Slide

28. 2Single
    Responsibility
    Principle
    

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29. 2
    A class should have

    one

    and only one

    reason to change
    

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30. 2(I added the next part)
    

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31. 2
    and when it does change

    you should try to

    preserve

    its public API
    

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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
    

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33. Smell!
    !
    Too many public methods
    make it unclear
    how a class is supposed to be used
    

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34. Public Methods

    communicate how a class can WILL BE used
    

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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
    

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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
    

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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
    

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38. Find methods only used internally

    and hide them
    

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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
    

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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
    

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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
    

    View Slide

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
    

    View Slide

43. Smell!
    !
    When an object's public methods must be invoked

    in a specific order to properly use it
    

    View Slide

44. Object Instantiation Rules
    

    View Slide

45. An object should be
    !
    ready to use and impossible to misuse!
    !
    after it has been instantiated
    Object Instantiation Rules
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

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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
    

    View Slide

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);

    }

    }
    

    View Slide

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);

    }

    

    View Slide

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);

    }

    

    View Slide

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);

    }

    

    View Slide

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);

    }

    }
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

62. An object’s configuration
    should not change after instantiation
    API Design Principles
    

    View Slide

63. An object’s configuration
    should not change after instantiation
    If you need a different configuration
    create another instance
    API Design Principles
    

    View Slide

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
    

    View Slide

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
    

    View Slide

66. View Slide

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
    

    View Slide

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
    

    View Slide

69. Do not expose getters for values you don’t use yset
    Do not expose getters for configuration
    API Design Principles
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

73. View Slide

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);

    }

    }
    

    View Slide

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);

    }

    }
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

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79. Class and Methods Principles
    

    View Slide

80. Class and Methods Principles
    STATELESS
    Do not store data during execution
    

    View Slide

81. Class and Methods Principles
    STATELESS
    Do not store data during execution
    DETERMINISTIC
    Given the same input, the return value is identical
    

    View Slide

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
    

    View Slide

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);

    }

    }
    

    View Slide

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);

    }

    }
    

    View Slide

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);

    }
    }
    

    View Slide

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);

    }
    }
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

    View Slide

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
    

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98. View Slide

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
    

    View Slide

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
     

     View Slide

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
     

     View Slide

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
     

     View Slide

103. View Slide

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
     

     

     View Slide

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
     

     View Slide

106. Questions
     John Kary
     Code Slinger, Build Breaker
     @johnkary
     http://johnkary.net/talks
     

     View Slide