public function setDefaultConstraint(string $placeholder): RouteCollectionInterface
	{
		if (array_key_exists($placeholder, $this->placeholders))
		{
			$this->defaultPlaceholder = $placeholder;
		}

		return $this;
	}
public function setDefaultConstraint(string $placeholder): RouteCollectionInterface
	{
		if (array_key_exists($placeholder, $this->placeholders))
		{
			$this->defaultPlaceholder = $placeholder;
		}

		return $this;
	}
public function setDefaultConstraint ( string $ placeholder ) : RouteCollectionInterface { if ( array_key_exists ( $ placeholder , $ this -> placeholders ) ) { $ this -> defaultPlaceholder = $ placeholder ; } return $ this ; }
Sets the default constraint to be used in the system. Typically
for use with the 'resource' method.

@param string $placeholder

@return RouteCollectionInterface
Sets the default constraint to be used in the system . Typically for use with the resource method .