calling the funciton name

[Vishal Kumar Aruru]

Hi,

I have a scenario where i am getting the function name from another class, so i am storing it in a string. Then i need to call the function which is in string.

for example i got some function name like "sampleFunction" then i store this name in a string. i need to trigger this function in the next step. how to do this.

Thanks in advance

[Mazer Lao Tzu]

In order to accomplish this, you will need to use java reflection which is often considered an advanced topic in java.

The method you will need to use is the invoke method on the Method class.

I encourage you to do a google search on 'java reflection' and pick a tutorial to read in order to learn how to use the reflection libraries.

[Wouter Oet]

Could you give us a small description of the problem you're trying to solve using reflection.
Because most of the time reflection is not necessary and the problem can be solved in a better way.

[Vishal Kumar Aruru]

Thanks,

But here my scenario is different, when i use method.invoke() function it returns an object, which i don't want this. My function returns a list of classes. So, when i use method.invoke() function, i need to typecast the list of the classes. but i will get the class name dynamically, so how to use this for a generic way.

Let me narrate you.

I will send a classname as parameter to a fucntion. that function will gets the fields name, in that fields having any list type fields, I have to traverse in to that list. So for traversing i used the getter of that list and i invoked that function it returns object. but i need to typecast the list of the classes. but i will get the class name dynamically, so how to use this for a generic way.

[Campbell Ritchie]

That sounds too difficult for "beginning". Moving thread

[salvin francis]

Vishal Kumar Aruru wrote:Thanks,

But here my scenario is different, when i use method.invoke() function it returns an object, which i don't want this. My function returns a list of classes. So, when i use method.invoke() function, i need to typecast the list of the classes. but i will get the class name dynamically, so how to use this for a generic way.

Let me narrate you.

I will send a classname as parameter to a fucntion. that function will gets the fields name, in that fields having any list type fields, I have to traverse in to that list. So for traversing i used the getter of that list and i invoked that function it returns object. but i need to typecast the list of the classes. but i will get the class name dynamically, so how to use this for a generic way.

This kinda smells more of a polymorphism and less of a reflection to me,
Should'nt interfact solve such issues ?

Vishal Kumar Aruru wrote:i will get the class name dynamically

- Builder pattern.

[Henry Wong]

Vishal Kumar Aruru wrote:
But here my scenario is different, when i use method.invoke() function it returns an object, which i don't want this. My function returns a list of classes. So, when i use method.invoke() function, i need to typecast the list of the classes. but i will get the class name dynamically, so how to use this for a generic way.

It doesn't matter if your function returns a list of classes. A "list of classes" IS-A object. Heck, it doesn't even matter if the method returns primatives (which aren't objects). The invoke() method will box any primitives returns for you, and hence, the return IS-A object.

Another reflection items which may help. The Method object has a method that tells you what is the type being returned.

Henry

[Mazer Lao Tzu]

Sorry, but I think I am having trouble with your English. I am having trouble understanding the following:

that function will gets the fields name, in that fields having any list type fields, I have to traverse in to that list. So for traversing i used the getter of that list

Are you retrieving a list of all of the fields of the class and then invoking a getter for any of the fields that have a type implementing java.util.List?

I agree with Wouter Oet and salvin francis: it sounds like your solution to whatever problem you are trying to solve is an overcomplicated one. There could be a much more straightforward approach.