I need help with my java code  It needs to Implement a semantic analyzer: For this simple example, the semantic analysis is done during parsing. If you want to extend this code to support more features of your SPL, you would need to build an AST and perform semantic analysis on that. import java.util.*;       public class SimpleCalculator {   private final String input;   private int position;       public SimpleCalculator(String input) {   this.input = input;   this.position = 0;   }       public static void main(String[] args) {   SimpleCalculator calculator = new SimpleCalculator("3 + 5 * (2 - 1)");   int result = calculator.parseExpression();   System.out.println("Result: " + result);   }       public int parseExpression() {   int value = parseTerm();       while (true) {   if (consume('+')) {   value += parseTerm();   } else if (consume('-')) {   value -= parseTerm();   } else {   break;   }   }       return value;   }       public int parseTerm() {   int value = parseFactor();       while (true) {   if (consume('*')) {   value *= parseFactor();   } else if (consume('/')) {   value /= parseFactor();   } else {   break;   }   }       return value;   }       public int parseFactor() {   if (consume('(')) {   int value = parseExpression();   consume(')');   return value;   }       StringBuilder sb = new StringBuilder();   while (Character.isDigit(peek())) {   sb.append(consume());   }       return Integer.parseInt(sb.toString());   }       private char consume() {   return input.charAt(position++);   }       private boolean consume(char c) {   if (peek() == c) {   position++;   return true;   }       return false;   }       private char peek() {   return position < input.length() ? input.charAt(position) : '\0';   }   }