April 2006
Intermediate to advanced
480 pages
8h 32m
English
Content preview from Design Patterns in Java™, Second Edition
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24 Command
THE ORDINARY WAY to cause a method to execute is to call it. There may be times, though, when you cannot control the timing of or the context in which a method should execute. In these situations, you can encapsulate a method inside an object. By storing the information necessary for invoking a method in an object, you can pass the method as a parameter, allowing a client or a service to determine when to invoke the method.
The intent of the COMMAND pattern is to encapsulate a request in an object.
A Classic Example: Menu Commands
Toolkits that support menus usually apply the COMMAND pattern. Each menu item is outfitted with an object that knows how to behave when the user clicks the item. This design keeps GUI logic ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.