From cc93827b8fabe176cebe0c2cf16a64820dbba166 Mon Sep 17 00:00:00 2001 From: Trismegiste Date: Sat, 11 May 2013 16:57:41 +0200 Subject: [PATCH] first, some comments --- Command/Command.php | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/Command/Command.php b/Command/Command.php index 5144a76..60e09ad 100644 --- a/Command/Command.php +++ b/Command/Command.php @@ -5,11 +5,19 @@ namespace DesignPatterns; /** * Command pattern * - * Purpose: - * to build a simple interface for commands that can all be run by just executing a single method they all have in - * common, often called 'run' or 'execute' + * Purpose: To encapsulate invocation and decoupling + * + * We have an Invoker and a Receiver. This pattern use a "Command" to delegate the + * method call against the Receiver and use the same method "execute". + * Therefore, the Invoker just know to call "execute" to process the Command of + * the client. + * + * The second aspect of ths pattern is the undo(), which undoes the method execute() + * Command can also be agregated to combine more complex commands with minimum + * copy-paste and relying on composition over inheritance. * * Examples: + * - A text editor : all events are Command which can be undone, stacked and saved. * - Symfony2: SF2 Commands that can be run from the CLI are built with just the Command pattern in mind * - big CLI tools use subcommands to distribute various tasks and pack them in "modules", each of these * can be implemented with the Command pattern (e.g. vagrant)