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javagenerics

Converting method call to the java.lang.reflect.Method object of that method


I am struggling trying to convert a 'method call' to the 'method object' of that method.

I have:

someClassInstance.someInstanceMethod(new Function<Person, Method>() {
     @Override
     public Method apply(Person p) {
         return p.getAge(); // I want to convert 'p.getAge()' to the the method of 'getAge'
     }
 });

I know I can simplify this with lambda's but I thought this would make what I want to do more clear.

p.getAge() currently returns an 'int', but I want it to return the 'Method object' of 'getAge()'. What I Mean by the 'Method object' is this:

 Method method = Person.class.getMethod("getAge"); // I basically want to return this.

The reason for this is, I'm building my own little framework to gain experience and letting the user use:

someClassInstance.someInstanceObject((Function<Person, Method>) o -> o.getAge());

Seems more user friendly.

NOTE: I do have my own interface of 'Function' that does not take 'Method' as a second generic type so the user only has to type:

someClassInstance.<Person>someInstanceMethod(o -> o.getAge());

Solution

  • After searching for some more days I finally found an answer, somewhere in the comments of an old stack overflow question, I found this answer from another question which links to a library written by 'Benji Weber'. This library used 'cglib' to create proxy objects to get the method of a Function<T, U>.

    Meaning:

     someMethod(Person::getAge) //returns a String 'age'.