How to use lambdas in "template" [closed]

Question

I have an event handling code, something like

void handleEventType1(EventType1 event1) {
    if (someCheck()){
        function1(event);
        postCheckTrue();
    } else {
        function2(event);
        postCheckFalse();
    }
}

void handleEventType2(EventType2 event2) {
    if (someCheck()){
        function3(event);
        postCheckTrue();
    } else {
        function4(event);
        postCheckFalse();
    }
}

I was hoping, I can do something like

handleEvent(event1, Handler::function1, Handler::function2);
handleEvent(event2, Handler::function3, Handler::function4);

that will somehow call functions (1 or 2) or (3 or 4), but I'm somehow not able to solve it to my satisfaction.

Answer 1

First, lets use inheritance. We will inherit the specific event types from the event interface.

interface Event {}

class EventType1 implements Event{}

class EventType2 implements Event{}

Secondly, lets define the type of functions that we will call in the handleEvent() method. In this case it is Consumer<Event>

Now our handleEvent() function will look like this

void handleEvent(Event event, 
                 Consumer<Event> option1, 
                 Consumer<Event> option2) {
   if (someCheck()) {
      option1.accept(event);
   } else {
       option2.accept(event);
   }
}

Now we can call this function and pass instance of event interface and two lambdas or method references

Handler.handleEvent(new EventType1(),
    event -> {
       //do something
    }, 
    event -> {
       //do something else;
    });
}