ParenthesisMatcher.java

/**
 * Created by cmb13162 on 20/10/14.
 */
public class ParenthesisMatcher {

    protected StackADT<Character> stack;

    // a constructor

    public ParenthesisMatcher(StackADT<Character> stackInterface) {

        this.stack = stackInterface;

    }

    public boolean isParenthesisMatch(String str) {


        for (int i = 0; i < str.length(); i++)
        {
            char current = str.charAt(i);

            switch (current) {

                case '{':
                case '(':
                case '[':
                    this.stack.push(current);
                    break;

                case '}':
                case ')':
                case ']':

                    if (stack.isEmpty()) {
                        return false;
                    }

                    char last = stack.top();

                    if ((current == '}' && last == '{') || (current == ')' && last == '(') || (current == ']' && last == '[') ) {
                        stack.pop();
                    }
                    else {
                        return false;
                    }
                    break;

            }

        }

        return stack.isEmpty();
    }
}