Question

Can I access a Class attribute by its name?

for example:

class Test {
    Integer GoodVar;
    Integer BadVar;
    ...

    void Func(String name, Integer value) {
        // Set A Value based on its name
    }

    void Init() {
        Func("GoodVar", 2);
        Func("BadVar", 1);
    }
}

can somebody code Func function?

Answer 1

You can use a switch statement, in JDK 7 the strings are allowed (see: http://docs.oracle.com/javase/7/docs/technotes/guides/language/strings-switch.html). Something like:

switch (name) {
     case "GoodVar":
         GoodVar = value;
         break;
     case "BadVar":
         BadVar = value;
         break;
     default:
         throw new IllegalArgumentException("Invalid name: " + name);
 }

Pre JDK 7 you can use if statements instead.
Another approach it would be to use reflection (see: http://docs.oracle.com/javase/tutorial/reflect/index.html), but it’s slow, like:

Field f = getClass().getField(name);
if (f!=null){
 f.setAccessible(true);
 f.setInt(this, value);
}else
  throw new IllegalArgumentException("Invalid name: " + name);