command-pattern

Command Pattern

This pattern lets us separate action logic from elements. We could group commands and execute them associating them to an item class.

classDiagram
    Command <|-- ConcreteCommand1
    Command <|-- ConcreteCommand2

    class Command{
      execute()
    }

    class ConcreteCommand1{
        execute()
    }

    class ConcreteCommand2{
        execute()
    }

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In this example, we have commands that define logic for invoices. This logic can be associated with invoice class and executed when an event is launched. Another way of using commands is to create separate logic and parse the item class directly to the command as a parameter and execute the command.

A command should have only a method to execute or run.

classDiagram
    Command <|-- ChargeStatusCommand
    Command <|-- SendEmailCommand
    Command <-- Invoice

    class Command{
      run()
    }

    class ChargeStatusCommand{
        run()
    }

    class SendEmailCommand{
        run()
    }

    class Invoice{
      @commands
    }

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Try it

In your console execute:

ruby command-pattern/working-example/example.rb