Add numbers with the word "add"

Question

I am writing to offer an application in Java right now and instead of using the operator "+", the user of the application can literally use the word "add" to add two numbers together.

I'm quite stuck on how to do this because I can't really use a method in order to complete the function considering I'd have to type "add()" rather than just "add". Unless there is a way to execute a method without the parentheses. Would I have to write a completely new class or is there an easier way to do this?

Answer 1

(An expansion on the idea presented by user710502)

You can use reflection.

double a = Double.parseDouble(some user input);
double b = Double.parseDouble(some user input);
String operation = some user input; // i.e. "add", "subtract"
Method operator = Calculations.class.getMethod(operation, double.class, double.class);
// NoSuchMethodException is thrown if method of operation name isn't found
double result = (Double) operator.invoke(null, a, b);

In some sort of calculations class:

public static double add(double a, double b) {
    return a + b;
}

public static double subtract(double a, double b) {
    return a - b;
}

// and so forth