Question

I have a clas called as MyFunctions that defines different functions func1, func2, etc. Also I have a class Process that stores the function name assigned to the object of this class:

Process p1 = new Process();
String fName1 = "func1";
p1.setFunctionName(fName1); 
Process p2 = new Process();
String fName2 = "func2";
p2.setFunctionName(fName2); 

In order to run a proper function, I do the following:

MyFunctions f = new MyFunctions();
if (p.getFunctionName() == "func1") {
   output = f.func1(inputdata);
} else if (p.getFunctionName() == "func2") {
   output = f.func2(inputdata);
}

I´m not sure that this approach is efficient. Is there any other way to solve this task?

Another question: is it possible to do something like this in JAVA?:

String fName = p.getFunctionName();
output = f."+fName+"(input);

Answer 1

First, this approach is not exactly correct. Never use == to compare objects. Use equals() instead:

MyFunctions f = new MyFunctions();
if ("func1".equals(p.getFunctionName())) {
   output = f.func1(inputdata);
} else if ("func2".equals(p.getFunctionName())) {
   output = f.func2(inputdata);
}

Second, I’d suggest you to use enum instead.

public enum FunctionInvoker {
    func1 {
        public Object invoke(MyFunctions o, Object ... arg) {
             o.func1(arg[0]);
        }
    },
    func2 {
        public Object invoke(MyFunctions o, Object ... arg) {
             o.func2(arg[0], arg[1]);
        }
    },
}

Now the usage looks like:

String functionName = ...; // probably read from file, etc.
Object result = FunctionInvoker.valueOf(functionName).invoke(args);