How to call Java function from string stored in a Variable

Question

Possible Duplicate:
Calling a method named “string” at runtime in Java and C

I need to be able to call a function, but the function name is stored in a variable, is this possible. e.g:

public void foo ()
{
     //code here
}

public void bar ()
{
     //code here
}

String functionName = "foo";

// i need to call the function based on what is functionName

Anyhelp would be great, thanks

Answer 1

Yes, you can, using reflection. However, consider also Effective Java 2nd Edition, Item 53: Prefer interfaces to reflection. If at all possible, use interfaces instead. Reflection is rarely truly needed in general application code.

See also

• Java Tutorials/Reflection API
• Java Advanced Language Topics/Reflection

Related questions

• Calling a method named “string” at runtime in Java and C

Answer 2

Easily done with reflection. Some examples here and here.

The main bits of code being

String aMethod = "myMethod";

Object iClass = thisClass.newInstance();
// get the method
Method thisMethod = thisClass.getDeclaredMethod(aMethod, params);
// call the method
thisMethod.invoke(iClass, paramsObj);

Answer 3

Use reflection.

Here's an example

Answer 4

With the reflection API. Something like this:

    Method method = getClass().getDeclaredMethod(functionName);
    method.invoke(this);