Managing collection of items through adding/removing - php

Question

I want have an in-memory data structure to be able to add or remove an item (in this instance a student) into some sort of table (just like a shopping cart) from the collection class I have created. At the moment, it just displays students. For instance, if I click add student, it will pop up below, and I can delete this student from below also.
How I could implement this?
Here is my Member.php class
<?php
class Member {
private $name;
private $age;
private $gender;
private $course;
public function __construct($name,$age, $gender, $course){
$this->name = $name;
$this->age = $age;
$this->gender = $gender;
$this->course = $course;
}
public function setName($name) { //Sets the age value
$this->name = $name;
}
public function setAge($age) { //Sets the age value
$this->age = $age;
}
public function setGender($gender) { //Sets the gender value
$this->gender = $gender;
}
public function setCourse ($course) {
$this->course = $course;
}
public function getName() { //Gets the name value
return $this->name;
}
public function getAge() { //Gets the age value
return $this->age;
}
public function getGender() { //Gets the gender value
return $this->gender;
}
public function getCourse() {
return $this->course;
}
}
?>
Here is my ObjectCollection.php
<?php
class ObjectCollection
{
//This is an array to hold line items
private $items_array ;
private $itemCounter; //Count the number of items
public function __construct() {
//Create an array object to hold line items
$this->items_array = array();
$this->itemCounter=0;
}
public function getItemCount(){
return $this->itemCounter;
}
public function addItem($item) {
$this->itemCounter++;
$this->items_array[] = $item;
}
public function getItem($index) {
return $this->items_array[$index];
}
}
?>
And finally displaying this through testcollection.php
<?php
$ObjColl = new ObjectCollection();
$member1 = new Member("Jessica Davidson", 21, "Female", "Computing");
$ObjColl->addItem($member1);
$member2 = new Member("Lucy Barnes", 22, "Female", "History");
$ObjColl->addItem($member2);
$member3 = new Member("Mark Smith", 24, "Male", "Social Science");
$ObjColl->addItem($member3);
for($i = 0;$i < $ObjColl->getItemCount();$i++){
$item = $ObjColl->getItem($i);
if ($item instanceof Member) {
print "<br> University Member: ";
}
print "Name: " . $item->getName();
print ". Age: " . $item->getAge();
print ". Gender: " . $item->getGender();
print ". Enrolled on: " .$item->getCourse() . " course<br>";
}
?>

Answer 1

At first if your ObjectCollection must collect only objects of Member class, use parameter type declaration. It’s good practice in OOP.
public function addItem(Member $item)
At second if you want work with ObjectCollection like with array, implement ArrayAccess and Iterator interfaces.
Example
<?php
class Member{
private $__name;
public function __construct($name){
$this->__name = $name;
}
public function getName(){
return $this->__name;
}
}
class MemberCollection implements ArrayAccess, Iterator{
private $__Collection = [];
private $__position = 0;
public function __construct(){
}
public function offsetSet($offset, $value) {
if (is_null($offset)) {
$this->__Collection[] = $value;
} else {
$this->__Collection[$offset] = $value;
}
}
public function offsetExists($offset) {
return isset($this->__Collection[$offset]);
}
public function offsetUnset($offset) {
unset($this->__Collection[$offset]);
}
public function offsetGet($offset) {
return isset($this->__Collection[$offset]) ? $this->__Collection[$offset] : null;
}
function rewind() {
$this->__position = 0;
}
function current() {
return $this->__Collection[$this->__position];
}
function key() {
return $this->__position;
}
function next() {
++$this->__position;
}
function valid() {
return isset($this->__Collection[$this->__position]);
}
public function addItem(Member $Member){
$this->offsetSet(null, $Member);
}
}
$MC = new MemberCollection();
$Member1 = new Member('Name 1');
$Member2 = new Member('Name 2');
$MC->addItem($Member1);
$MC->addItem($Member2);
foreach ($MC as $Member){
echo '<br>' . $MC->key() . ':<br>';
var_dump($Member->getName());
}
unset($MC[0]); //Delete member from collection
?>