CheckBalanced2.java

import java.io.*;
import java.util.LinkedList;
import java.util.Scanner;

public class CheckBalanced2 {

    /**
    *   Program: CheckBalanced2.java
    *   Purpose: Read a Java source code file and check it has balanced brackets {}()[].
    *       Do not include brackets within quotes or comments.
    *   Creator: Chris Clarke
    *   Created: 13.11.2015
    */

    // create linked list object as instance variable
    LinkedList<Integer> list = new LinkedList<Integer>();

    // initialise top (of stack)
    static int top = -1;

    public void push(int t) {
        list.add(new Integer(t));
    } // push()

    public int pop() {
        if (top != -1)
            return list.remove(top);
        return top;
    } // pop()

    public static void doBalanceCheck(char ch0, char ch1, CheckBalanced2 stack, String javaSource) {
        File f;
        Scanner scan = null;
        String line;
        char ch;
        int lineNum = 0;
        int openLineNum = 0;
        int position = 0;
        top = -1;
        boolean inSingleQuotes = false;
        boolean inDoubleQuotes = false;
        boolean inMultiLineComment = false;

        System.out.printf("%c %c: ", ch0, ch1);

        try {
            f = new File(javaSource);
            scan = new Scanner(f);
        } catch (IOException e) {
            System.out.println("Caught IOException");
            return;
        } // try

        while (scan.hasNextLine()) {
            line = scan.nextLine();
            for (int i=0; i<line.length(); i++) {
                ch = line.charAt(i);
                if (ch=='\"') {
                    inDoubleQuotes = !inDoubleQuotes;
                } else if (ch=='\'') {
                    inSingleQuotes = !inSingleQuotes;
                } else if (ch=='/' && i<line.length()-1) {
                    if (line.charAt(i+1)=='/') {
                        break; // ignore rest of line
                    } else if (line.charAt(i+1)=='*') {
                        inMultiLineComment = true;
                    }
                } else if (ch=='*' && i<line.length()-1) {
                    if (line.charAt(i+1)=='/') {
                        inMultiLineComment = false;
                    }
                }
                if (!inDoubleQuotes && !inSingleQuotes && !inMultiLineComment) {
                    if (ch==ch0) {
                        stack.push(++top);
                        openLineNum = lineNum;
                        position = i;
                    }
                    if (ch==ch1) {
                        stack.pop();
                        top--;
                    }
                } // if
            } // for
            lineNum++;
        } // while

        if (scan!=null) scan.close();

        if (top == -1) System.out.printf("BALANCED%n");
        else System.out.printf("NOT BALANCED at line %d, position %d%n", openLineNum+1, position+1);
    } // doBalanceCheck()

    public static void main(String[] args) {
        CheckBalanced2 myStack = new CheckBalanced2();
        if (args.length==0) {
            System.out.println("Usage: java CheckBalanced2 \"MyProgram.java\"");
        } else {
            myStack.doBalanceCheck('{', '}', myStack, args[0]);
            myStack.doBalanceCheck('(', ')', myStack, args[0]);
            myStack.doBalanceCheck('[', ']', myStack, args[0]);
        } // if
    } // main()

} // class CheckBalanced2