add setter methods to a PHP Exception

TExceptionSetterMethods.php

<?php
namespace My\Exception;

use Exception;
use ReflectionProperty;

/**
 * Fluent cq chaining setter methods for an Exception class.
 *  To set or modify an Exception's properties after construction.
 *
 * Although it is a little flaky to make these one-time-set properties alterable,
 *  it is usable to prevent having a `$code` and `$previous` argument for all your
 *  {@link http://rosstuck.com/formatting-exception-messages/ custom exception messages}.
 * <code><?php
 * class MyCustomException extends \Exception {
 *     use TFluentExceptionMethods;
 *     static function someExceptionalSituation() {
 *         return new self("Something specific went wrong.");
 *     }
 * }
 * function someUnreliableFunction() {
 *     try {
 *         unexistingMethod();
 *     } catch (\Exception $e) {
 *         throw MyCustomException::someExceptionalSituation()->setPrevious($e);
 *     }
 * }
 * </code>
 */
trait TExceptionSetterMethods
{
    /**
     * @param string $message
     * @return static
     */
    public function setMessage($message)
    {
        $this->message = (string)$message;
        return $this;
    }
    
    /**
     * @param string $code
     * @return static
     */
    public function setCode($code)
    {
        $this->code = (int)$code;
        return $this;
    }
    
    /**
     * @param Exception $previous
     * @return static
     */
    public function setPrevious(Exception $previous)
    {
        // 'previous' property is private to the Exception class.
        $previousProp = new ReflectionProperty(Exception::class, "previous");
        $previousProp->setAccessible(true);
        $previousProp->setValue($this, $previous);
        $previousProp->setAccessible(false);

        return $this;
    }
}