哦!(“(”)。equals(stack.peek())工作不正常

最近,我一直在通过在java中实现堆栈来创建计算器。我遇到了一些麻烦 stack.peek().equals("(") 在我的代码中,我尝试了几种不同的方法来解决这个问题,但似乎没有任何效果。

下面是我的代码:

import java.util.Scanner;
import java.util.Stack;
public class URCalculator {

    public static Scanner scan = new Scanner(System.in);
    public static Stack<String> uRStack = new Stack<String>();
    public static Stack<String> uROPStack = new Stack<String>();

    public static void main(String[] args) {
        prompt();
        String val = scan.next();

        pusher(splitInput(val));
        while(!uRStack.empty()) {
            System.out.println(uRStack.pop());
        }
    }
    public static String[] splitInput(String val) {
        return val.split("(?!^)");
    }

    public static void pusher(String[] s) {
        int counter = 0; // counter determines if there is a numeric value     
in the index prior, if so then we concatenate and add back to the stack.
        for(int i=0; i<s.length; i++) { // loops through split input array 
            if(isNumeric(s[i]) && counter != 0) { // checks if number and if 
previous number 
                pushNumeric(uRStack.pop() + s[i]);
                counter++;
            }
            else if (isNumeric(s[i])) { // checks if just a number
                pushNumeric(s[i]);
                counter++;
            }
            else if(isOperator(s[i])) { // if not number  then reset counter for latter values
                addOperator(s[i]);
                counter=0;
            }           
        }
        uRStack.push(uROPStack.pop());

     }
    public static void addOperator(String s) { // uses cases to determine logic for operator stack
    switch(s) {
    case "+": 

        if(!uROPStack.empty()){
            while(!"(".equals(uROPStack.peek()) && !uROPStack.empty()) { // while operators not of lower precedence then push pop
                uRStack.push(uROPStack.pop());
            }
        }
        uROPStack.push(s);
        break;

    case "-":

        if(!uROPStack.empty()){
            while(!"(".equals(uROPStack.peek()) && !uROPStack.empty()) { // while operators not of lower precedence then push pop
                uRStack.push(uROPStack.pop());
            }
        }
        uROPStack.push(s);
        break;

    case "*":

        if(!uROPStack.empty()) {
            while("*".equals(uROPStack.peek()) || !"/".equals(uROPStack.peek())) { // while operators of equal or greater precedence then push pop
                uRStack.push(uROPStack.pop());
            }
        }
        uROPStack.push(s);
        break;

    case "/":

        if(!uROPStack.empty()) {
            while("*".equals(uROPStack.peek()) || !"/".equals(uROPStack.peek())) { // while operators of equal or greater precedenc then push pop
                uRStack.push(uROPStack.pop());
            }
        }
        uROPStack.push(s);
        break;

    case "(":

        uROPStack.push(s);
        break;

    case ")":
        if(!uROPStack.empty()){
            while(!"(".equals(uROPStack.peek())) {
                uRStack.push(uROPStack.pop());
            }
        }
        break;

    }

}

我已经为上下文添加了main和pusher方法,但真正的问题在于addOperation方法,特别是while循环中的第一个布尔值。我收到的错误发布在下面:

    Hello and welcome to the URCalculator. Please type an operation
    1-2-3-4-5
    Exception in thread "main" java.util.EmptyStackException
    at java.util.Stack.peek(Unknown Source)
    at URCalculator.addOperator(URCalculator.java:129)
    at URCalculator.pusher(URCalculator.java:107)
    at URCalculator.main(URCalculator.java:14)

我知道我的代码不是最优雅的,也没有完成,但我似乎不明白为什么我会收到错误。我检查过的一件事是,当我移除 !"(".equals(uROPStack.peek()) 从整体上看,事情似乎进展顺利。问题是我仍然需要处理堆栈中的偏执案例,所以我不知道该怎么办。