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We will use the simple program that generates a report for us as an example.

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So let's study a bit abstraction first so we have the simple interface here that has only one method

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that doesn't return anything.

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And this interface is implemented in this class called general report operation.

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So this is basically the command, the equivalent of a command in the terminology of the command pattern.

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Of course, you can have multiple commands, but for the sake of simplicity, just stick with having

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a single command coded here.

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So this is the receiver object.

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And you can see the pattern is making use of composition to store a reference to it and execute method

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will create an instance of the receiver object and it will call the generic method from from from the

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object itself.

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Let's take a look at the receiver object.

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You can see that the only outputs some lines in the console.

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So it's supposed to show when the report is being generated and when the report has been generated,

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when the process basically is is finished.

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This is the Invoker class.

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So this knows how to execute the commands.

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So it has this execute operation method here.

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The execute operation will take on object of this interface as an argument, and it will call the execute

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method that is inside of this object.

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Let's take a look at the grant application.

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So the current application here, we create new Invoker object.

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And here, as you can see, we create a new general report operation because this is the only command

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that we can run as part of this program.

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So this will eventually call this execute method here.

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Right.

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So let's start let's run this.

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And as you can see, we have the desired output here.

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So it basically ran the commands for generating the report.

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That's it for this pattern.

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Join me in the next video where we are going to discuss about the interpreter, Peter.