Execute a function "before each" method of the same class in java

Question

I have several methods in a class that require a boolean to be set to true in order to execute correctly.

I could write the if statement in each method, but it is not convenient if I or someone else wants to ad another method. I or he could forget about the check.

Is there a way in java to execute a method before each other methods (exactly like JUnit does with @BeforeEach ) in a class ?

Edit: Lots of very interesting techniques/answers/concepts proposed. I'll be in touch when I've understood them. Thanks.

Answer 1

Lets make a method turnBooleanTrue() where effectively the boolean is set to true in order for the method to be execute correctly.

Then, you can write up your very own InvocationHandler that would intercept calls to your objects, and then reflectively (using reflection API) invoke first the turnBooleanTrue() method followed by the method to which the call was made.

Will look something like this

public class MyClassInvocationHandler implements InvocationHandler {

    // initiate an instance of the class
    MyClass myClass = new MyClassImpl();

    @Override
    public Object invoke(Object proxy, Method method, Object[] args)
            throws Throwable {

        // look up turnBooleanTrue() method
        Method turnBooleanTrue = myClass.getClass().getMethod("turnBooleanTrue");

        // invoke the method
        turnBooleanTrue.invoke(...); // toggle the boolean

        // invoke the method to which the call was made
        // pass in instance of class
        Object returnObj = method.invoke(myClass, args);

        return returnObj;
}

EDIT

Added some lines to have an object of MyClass initialized. You need something to invoke the method on and maintain the state. Changed util to myClass in the code example above.

Answer 2

Considering my use case, it was a bit overkill to use AOP or other concepts. So I basically did a check in each functions.