Example of using Iterator, Countable, ArrayAccess, JsonSerializable and Serializable PHP interfaces

Collection.php

<?php

namespace Aperitips;

/**
 * Class Collection.
 *
 * Example of using Iterator, Countable, ArrayAccess, JsonSerializable and Serializable interfaces
 *
 * @author Romain Monteil <[email protected]>
 * @package Aperitips
 */
class Collection implements \Iterator, \Countable, \ArrayAccess, \JsonSerializable, \Serializable
{
    /**
     * @var integer
     */
    protected $index = 0;

    /**
     * @var array
     */
    protected $entries = [];

    /**
     * Collection constructor.
     *
     * @param array $array
     */
    public function __construct(array $array = [])
    {
        foreach ($array as $value) {
            $this->entries[] = $value;
        }
    }

    /**
     * @return mixed
     */
    public function current()
    {
        return $this->entries[$this->index];
    }

    public function next(): void
    {
        ++$this->index;
    }

    /**
     * @return int|mixed
     */
    public function key()
    {
        return $this->index;
    }

    /**
     * @return bool
     */
    public function valid(): bool
    {
        return isset($this->entries[$this->index]);
    }

    public function rewind(): void
    {
        $this->index = 0;
    }

    /**
     * @param mixed $offset
     *
     * @return bool
     */
    public function offsetExists($offset): bool
    {
        return isset($this->entries[$offset]);
    }

    /**
     * @param mixed $offset
     *
     * @return mixed|null
     */
    public function offsetGet($offset)
    {
        return $this->entries[$offset] ?? null;
    }

    public function offsetSet($offset, $value): void
    {
        if ($offset === null) {
            $this->entries[] = $value;
        } else {
            $this->entries[$offset] = $value;
        }
    }

    public function offsetUnset($offset): void
    {
        unset($this->entries[$offset]);
    }

    public function count(): int
    {
        return \count($this->entries);
    }

    public function toArray(): array
    {
        return $this->entries;
    }

    /**
     * @return array
     */
    public function jsonSerialize(): array
    {
        return $this->toArray();
    }

    /**
     * @return string
     */
    public function serialize(): string
    {
        return serialize($this->entries);
    }

    /**
     * @param string $serialized
     */
    public function unserialize($serialized)
    {
        $this->entries = unserialize($serialized, [Collection::class]);
    }
}

$collection = new Collection([
    [
        'fistName' => 'Romain',
        'lastName' => 'Monteil',
        'age'      => 30,
        'frontEnd' => false,
        'backEnd'  => true,
        'designer' => false,
        'funny'    => 'HELL YEAH',
    ],
    [
        'fistName' => 'Matthieu',
        'lastName' => 'Pétel',
        'age'      => 26,
        'frontEnd' => true,
        'backEnd'  => false,
        'designer' => false,
        'funny'    => 'FUCK NO',
    ],
    [
        'fistName' => 'Simon',
        'lastName' => 'Kabab',
        'age'      => 23,
        'frontEnd' => false,
        'backEnd'  => false,
        'designer' => true,
        'funny'    => 'YEAH',
    ],
]);

echo "--------------------\n";
echo "\Countable\n";
echo "--------------------\n";
var_dump(\count($collection));

echo "\n";
echo "\n";

echo "--------------------\n";
echo "\Iterator\n";
echo "--------------------\n";
foreach ($collection as $key => $value) {
    var_dump($key, $value);
    echo "\n";
}

echo "\n";
echo "\n";

echo "--------------------\n";
echo "\ArrayAccess\n";
echo "--------------------\n";
var_dump($collection[0]);
var_dump(isset($collection[1]));

unset($collection[2]);
var_dump(isset($collection[2]));

$collection[] = [
    'fistName' => 'Thibault',
    'lastName' => 'Desmoulin',
    'age'      => 29,
    'frontEnd' => false,
    'backEnd'  => false,
    'designer' => false,
    'funny'    => 'HELL YEAH',
];
var_dump($collection);

echo "\n";
echo "\n";

echo "--------------------\n";
echo "\Serializable\n";
echo "--------------------\n";

$serialize = serialize($collection);
var_dump($serialize);

echo "\n";

$newCollection = unserialize($serialize, [Collection::class]);
var_dump($newCollection->toArray());

echo "\n";
echo "\n";

echo "--------------------\n";
echo "\JsonSerializable\n";
echo "--------------------\n";
var_dump(json_encode($collection));