Shorter solution to if,else if,else if

Question

I\'m looking for a way to shorten this code up and avoid repeating code and if statements. What I\'m doing is creating a calculator that searches strings for operators &quo

Answer 1

There's no need of switch statements and complex hierrachies of classes.

In order to simplify and shorten your code and calculate simple and complex expressions (represented as String objects), you can use the Java's JavaScript API and it's ScriptEngine class, which basically simulates a JavaScript console.

import javax.script.ScriptEngineManager;
import javax.script.ScriptEngine;

public class MyClass{
    public static void main(String[] args) throws Exception {
        // create a script engine manager
        ScriptEngineManager factory = new ScriptEngineManager();
        // create a JavaScript engine
        ScriptEngine engine = factory.getEngineByName("JavaScript");
        // evaluate JavaScript code from String
        System.out.println(engine.eval("(5+10)*2/3"));
    }
}

This will output: 10.0