Is it possible to pass arithmetic operators to a method in java?

Question

Right now I'm going to have to write a method that looks like this:

public String Calculate(String operator, double operand1, double operand2) {          if (operator.equals("+"))         {             return String.valueOf(operand1 + operand2);         }         else if (operator.equals("-"))         {             return String.valueOf(operand1 - operand2);         }         else if (operator.equals("*"))         {             return String.valueOf(operand1 * operand2);         }         else         {             return "error...";         } } 

It would be nice if I could write the code more like this:

public String Calculate(String Operator, Double Operand1, Double Operand2) {        return String.valueOf(Operand1 Operator Operand2); } 

So Operator would replace the Arithmetic Operators (+, -, *, /...)

Does anyone know if something like this is possible in java?

Answer 1

No, you can't do that in Java. The compiler needs to know what your operator is doing. What you could do instead is an enum:

public enum Operator {     ADDITION("+") {         @Override public double apply(double x1, double x2) {             return x1 + x2;         }     },     SUBTRACTION("-") {         @Override public double apply(double x1, double x2) {             return x1 - x2;         }     };     // You'd include other operators too...      private final String text;      private Operator(String text) {         this.text = text;     }      // Yes, enums *can* have abstract methods. This code compiles...     public abstract double apply(double x1, double x2);      @Override public String toString() {         return text;     } } 

You can then write a method like this:

public String calculate(Operator op, double x1, double x2) {     return String.valueOf(op.apply(x1, x2)); } 

And call it like this:

String foo = calculate(Operator.ADDITION, 3.5, 2); // Or just String bar = String.valueOf(Operator.ADDITION.apply(3.5, 2));