Proposal for iteratable/non-iteratable abstraction via callbacks (in php)

index.php

<?php 

class Person {
	protected $name;
	
	protected $age;
	
	public function __construct($name, $age){
        	$this->name = $name;
        	$this->age = $age;
    	}
	
	public function getName(){
		return $this->name;
	}
	
	public function getAge(){
		return $this->age;
	}
	
}

class Tester {
	// Array of all test objects
	protected $testObjects;
	
	public function __construct(array $data){
		$testObjArray = array();
		foreach($data as $key => $value){
			$testObj = new Person($key, $value);
			$testObjArray[] = $testObj;
		}	
		$this->testObjects = $testObjArray;
    	}
	
	public function setTestObjects(array $objArray){
		$this->testObjects = $objArray;
	}
	
	public function getTestObjects(){
		return $this->testObjects;
	}
	
	public function runTest($data, callable $onceCallback = NULL, callable $loopCallback = NULL){
		$testData = $this->getTestObjects();
		
		$dataArray = array();		
		$isList = count($testData) > 1;
        	$isItem = count($testData) === 1;
		$dataArray["isList"] = $isList;
		$dataArray["isItem"] = $isItem;
		$dataArray["extraData"] = $data;
		
		// Call once
		if($onceCallback !== NULL){
			$onceCallback($testData, $dataArray);
		}
		// If there is more then one test object
		// Run the callback inside a loop
		if($loopCallback !== NULL){
			if($isList){
				echo "Multiple items detected <br />";
				foreach($testData as $item){
					$loopCallback($item, $data);
				}				
				// Otherwise run the function once	
			}else if($isItem){
				echo "Single item detected <br />";
				$loopCallback($testData[0], $data);
			}
		}	
	}
	
}

// Create a list of people we want to create
$people = array(
	"John Doe" => "21",
	"Jane Doe" => "22"
);

$extraData = "Just an extra string";


$onceCallback = function($testData, $data){
	echo $data["extraData"]."<br />";
};

$loopCallback = function($item, $data){
	echo $item->getName()." : ".$item->getAge()."<br />";
};

// Pass that list into the tester
$personClassTester = new Tester($people);
$personClassTester->runTest($extraData, $onceCallback, $loopCallback);