How to define a Java function to acception a function

Question

I have a requirement of exception handling for all methods, suppose that I have a project and within the project, the StaleStateException is thrown, and I need to handle it, I want to do it like this:

class Util() {
    public static void handle(XXXX method) {
        try{
            //invoke method
        } catch(StaleStateException e) {
            //do something
        }
    }
}

How can I implement this method?

does [this](https://stackoverflow.com/questions/4685563/how-to-pass-a-function-as-a-parameter-in-java/21681010) help you? — amsjntz, Jun 21 '21 at 09:10
If you want to handle any method, then you probably want to use generic methods. — David Lee, Jun 21 '21 at 09:14
@DavidLee, Yes correct, I want to handle any methods and I want any of the method can be the parameter passed to this function — zhianABCD, Jun 21 '21 at 09:16
Do you need to pass arguments to the method and are there return values? Or is the signature always `void doSomething()`? — Matt, Jun 21 '21 at 09:20
@Matt, the method passed to this util method can be method with any argument and return type. — zhianABCD, Jun 21 '21 at 09:22
How do you expect to pass a method to `handle(...)` ? Reflection? The solution might be more confusing that just wrapping everything with try-catch... — rosaqq, Jun 21 '21 at 09:38
check this https://stackoverflow.com/questions/2186931/java-pass-method-as-parameter — Ashish Mishra, Jun 21 '21 at 09:49
Define a function to accept a function? That would be `Function, ?> function`. — MC Emperor, Jun 21 '21 at 10:05

SoT · Answer 1 · 2021-06-21T09:58:36.033

0

Function<InputType, Void> = input -> {
    // do stuff
    System.out.println(input.toString());
}

class Util() {
    public static void handle(Function<InputType, Void> method) {
        try{
            input.apply(input);
        } catch(StaleStateException e) {
            //do something
        }
    }
}

edited Jun 21 '21 at 09:58

answered Jun 21 '21 at 09:32

SoT

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36

you should use `catch` instead of `cache` – rosaqq Jun 21 '21 at 09:50
If the return type of the function is `void`, then a more appropriate interface to use is interface `Consumer` instead of `Function`. – Jesper Jun 21 '21 at 10:10

score 0 · Answer 2 · answered Jun 21 '21 at 09:41

Here is another way to do this:

public class Methods {
  public static void someMethodToPass(String s){
    System.out.println("Invoked, Here is the argument: " + s);
  }

  public static void invokerMethod(Method m) throws InvocationTargetException, IllegalAccessException {
    m.invoke(null,"Some argument");
  }

  public static void main(String[] args) {
    try {
        invokerMethod(Arrays.stream(Methods.class.getMethods()).filter(m -> m.getName().equals("someMethodToPass")).findFirst().get());
    } catch (InvocationTargetException | IllegalAccessException e) {
        e.printStackTrace();
    }
  }
}

Why not `Methods.class.getDeclaredMethod("someMethodToPass", String.class)` instead of `Arrays.stream(Methods.class.getMethods()).filter(m -> m.getName().equals("someMethodToPass")).findFirst().get()` ? Also, this is what I meant in my comment on the question. OP wanted to handle one type of exception with ease and now has a new method that throws 2 other exceptions he has to handle... — rosaqq, Jun 21 '21 at 09:48

How to define a Java function to acception a function

2 Answers2