Design and Architectural Principles - Java 8 Lambdas - page 119

}

We can now implement our Action interface for each of the operations. All these classes
need to do is call a single method on our Editor and wrap this call into our Action inter-
face. I'll name the classes after the operations that they wrap, with the appropriate class nam-
ing convention—so, the save method corresponds to a class called Save . Examples 8-3 and
8-4 are our command objects.

Example 8-3. Our save action delegates to the underlying method call on Editor
public public class class Save Save implements implements Action {

private private final final Editor editor ;

public public Save ( Editor editor ) {

this this . editor = editor ;

}

@Override
public

public void void perform () {

editor . save ();

}

}

Example 8-4. Our open action also delegates to the underlying method call on Editor
public public class class Open Open implements implements Action {

private private final final Editor editor ;

public public Open ( Editor editor ) {

this

this . editor = editor ;

}

@Override
public

public void void perform () {

editor . open ();

}

}

Now we can implement our Macro class. This class can record actions and run them as a
group. We use a List to store the sequence of actions and then call forEach in order to ex-
ecute each Action in turn. Example 8-5 is our invoker.