In object-oriented programming, the command pattern is a behavioural design pattern in which an object is used to represent and encapsulate all the information needed to call a method at a later time. This information includes the method name, the object that owns the method and values for the method parameters.
Three terms always associated with the command pattern are client, invoker and receiver. The client instantiates the command object and provides the information required to call the method at a later time. The invoker decides when the method should be called. The receiver is an instance of the class that contains the method's code.
Using command objects makes it easier to construct general components that need to delegate, sequence or execute method calls at a time of their choosing without the need to know the owner of the method or the method parameters.
Read more about Command Pattern: Uses, Structure, Terminology, Example
Famous quotes containing the words command and/or pattern:
“How did you get in the Navy? How did you get on our side? Ah, you ignorant, arrogant, ambitious—keeping sixty two men in prison cause you got a palm tree for the work they did. I don’t know which I hate worse, you or that malignant growth that stands outside your door. How did you ever get command of a ship? I realize in wartime they have to scrape the bottom of the barrel. But where’d they ever scrape you up?”
—Frank S. Nugent (1908–1965)
“Art is the imposing of a pattern on experience, and our aesthetic enjoyment is recognition of the pattern.”
—Alfred North Whitehead (1861–1947)