PHP/Design Patterns/Composite Pattern

PHP Design Patterns Composite

   <source lang="html4strict">

<?

abstract class StudentManager {
   abstract function getStudent($previousStudent);
   abstract function getStudentCount();
   abstract function setStudentCount($new_count);
   abstract function addStudent($oneStudent);
   abstract function removeStudent($oneStudent);
}
 

class SingleStudentClass extends StudentManager {

   private $firstName;
   private $lastName;
   function __construct($firstName, $lastName) {
     $this->firstName = $firstName;
     $this->lastName = $lastName;
   }
   function getStudent($studentToGet) {
     if (1 == $studentToGet) {
       return $this->firstName." by ".$this->lastName;
     } else {
       return FALSE;
     }
   }
   function getStudentCount() {
     return 1;
   }
   function setStudentCount($newCount) {
     return FALSE;
   }
   function addStudent($oneStudent) {
     return FALSE;
   }
   function removeStudent($oneStudent) {
     return FALSE;
   }
 }  
 
 

class MultipleStudentsClass extends StudentManager {

   private $oneStudents = array();
   private $studentCount;
   public function __construct() {
     $this->setStudentCount(0);
   }
   public function getStudentCount() {
     return $this->studentCount;
   }
   public function setStudentCount($newCount) {
     $this->studentCount = $newCount;
   }
   public function getStudent($studentToGet) {  
     if ($studentToGet <= $this->studentCount) {
       return $this->oneStudents[$studentToGet]->getStudent(1);
     } else {
       return FALSE;
     }
   }
   public function addStudent($oneStudent) {
     $this->setStudentCount($this->getStudentCount() + 1);
     $this->oneStudents[$this->getStudentCount()] = $oneStudent;
     return $this->getStudentCount();
   }
   public function removeStudent($oneStudent) {
     $counter = 0;
     while (++$counter <= $this->getStudentCount()) {
       if ($oneStudent->getStudent(1) == 
         $this->oneStudents[$counter]->getStudent(1)) {
         for ($x = $counter; $x < $this->getStudentCount(); $x++) {
           $this->oneStudents[$x] = $this->oneStudents[$x + 1];
         }
         $this->setStudentCount($this->getStudentCount() - 1);
       }
     }
     return $this->getStudentCount();
   }
 }
 
 

$firstStudent = new SingleStudentClass("A","B"); echo $firstStudent->getStudent(1); echo "
";

$secondStudent = new SingleStudentClass("C", "D"); echo $secondStudent->getStudent(1); echo "
"; $students = new MultipleStudentsClass(); $studentsCount = $students->addStudent($firstStudent); echo $students->getStudent($studentsCount); echo "
"; $studentsCount = $students->addStudent($secondStudent); echo $students->getStudent($studentsCount); echo "
"; $studentsCount = $students->removeStudent($firstStudent); echo $students->getStudentCount(); echo "
";

echo $students->getStudent(1); echo "
"; ?>

      </source>