[Immutable] #valueobject #immutable

ImmutableTrait.php

<?php

namespace Website\Traits;

trait ImmutableTrait
{
    /** @var bool  */
    private $constructorWasCalled = false;

    /**
     * ImmutableTrait constructor.
     * @throws \Exception
     */
    public function __construct()
    {
        if (true === $this->constructorWasCalled) {
            $this->throwImmutableException();
        }
        $this->constructorWasCalled = true;
    }

    /**
     * @param $name
     * @param $value
     * @throws \Exception
     */
    final public function __set($name, $value)
    {
        $this->throwImmutableException();
    }

    /**
     * @throws \Exception
     */
    final public function __clone()
    {
        $this->throwImmutableException();
    }

    /**
     * @return void
     * @throws \Exception
     */
    final private function throwImmutableException()
    {
        throw new \Exception("The object is immutable.");
    }
}