collection.php

<?php 

class Collection 
{
  public $pembayaran = array();
  public $cashier_summary = array();

  public function addItem( $obj, $key = null, $data = null)
  {
    if ($data === 1) {
      if ($key == null) {
        $this->pembayaran[] = $obj;
      }
      else {
        if (isset($this->pembayaran[$key])) {
          echo "Key $key already in use.";
        }
        else {
          $this->pembayaran[$key] = $obj;
        }
      }
    } else if ($data === 2) {
      if ($key == null) {
        $this->cashier_summary[] = $obj;
      }
      else {
        if (isset($this->cashier_summary[$key])) {
          echo "Key $key already in use.";
        }
        else {
          $this->cashier_summary[$key] = $obj;
        }
      }
    } else {
      return false;
    }

  }

  public function deleteItem($data = null, $key)
  {
    if ($data === 1) {
      if (isset($this->pembayaran[$key])) {
        unset($this->pembayaran[$key]);
      }
      else {
        echo "Invalid key $key.";
      }
    } else if ($data === 2) {
      if (isset($this->cashier_summary[$key])) {
        unset($this->cashier_summary[$key]);
      }
      else {
        echo "Invalid key $key.";
      }
    } else {
      return false;
    }

  }

  public function getItem($data = null, $key)
  {
    if ($data === 1) {
      if (isset($this->pembayaran[$key])) {
        return $this->pembayaran[$key];
      }
      else {
        echo "Invalid key $key.";
      }
    } else if ($data === 2) {
      if (isset($this->cashier_summary[$key])) {
        return $this->cashier_summary[$key];
      }
      else {
        echo "Invalid key $key.";
      }
    } else {
      return false;
    }

  }

  public function keysAvail($data = null) {
    if ($data === 1) {
      return array_keys($this->pembayaran);
    } else if ($data === 2) {
      return array_keys($this->cashier_summary);
    } else {
      return false;
    }
  }
}

CollectionModel.php

<?php 

class CollectionModel
{
  private $tipe;
  private $mata_uang;
  private $total_origin;
  private $total_idr;

  public function __construct($tipe, $mata_uang, $total_origin, $total_idr)
  {
    $this->tipe = $tipe;
    $this->mata_uang = $mata_uang;
    $this->total_origin = $total_origin;
    $this->total_idr = $total_idr;
  }
  
}

mainclass.php

<?php

// use this collection
class main
{
  
  public function logicMain() 
  {
    $c = new Collection();
    $c->addItem(new ShiftCashierCollection("Bayar", "IDR", 0, 12000), "BAYAR", 1);
    $c->addItem(new ShiftCashierCollection("Bayar", "IDR", 0, 12000), "KEMBALIAN", 1);

    $c->deleteItem(1, "payment");
    
    $c->keysAvail(1);
    $c->keysAvail(2);

    dd($c->getItem(1, "cashback"));
    
  }
  
}