src/Event/Listener.php
public function on($event, $callback) {
		if (!is_callable($callback)) {
			throw new ListenException(var_export($callback, true) . " is not callback");
		}
		$this->callback[$event] = $callback;
	}
public function on($event, $callback) {
		if (!is_callable($callback)) {
			throw new ListenException(var_export($callback, true) . " is not callback");
		}
		$this->callback[$event] = $callback;
	}
public function on ( $ event , $ callback ) { if ( ! is_callable ( $ callback ) ) { throw new ListenException ( var_export ( $ callback , true ) . " is not callback" ) ; } $ this -> callback [ $ event ] = $ callback ; }
Set event handler

@access public
@param string $event
@param callable $callback
Set event handler