sc.java

gistfile1.java

public class StringCalculator {

	public static int sum(String numberStr) {
		
		String defaultDelimiter = ",|\n";
		String[] numbers;
		
		if(newDelimiter(numberStr)){
			String newDelimiter = getNewDelimiter(numberStr);
			String newNumberStr = normalize(numberStr,newDelimiter);
			numbers = newNumberStr.substring(1, newNumberStr.length()).split(newDelimiter);
		}else numbers = numberStr.split(defaultDelimiter);
		
		if(isMultipeNumbers(numbers)) return sumMultipleNumbers(numbers);
		if ("".equals(numberStr)) return 0;
		return Integer.parseInt(numberStr);
		
	}

	private static String normalize(String numberStr, String newDelimiter) {
		String temp = numberStr.substring(3,numberStr.length());
		return temp.replaceAll("\n", newDelimiter);
	}

	private static String getNewDelimiter(String string) {
		String newDelimiter = string.substring(2, 3);
		return "\\"+newDelimiter;
	}

	private static boolean newDelimiter(String string) {
		return string.startsWith("//");
	}

	private static int sumMultipleNumbers(String[] numbers) {
		int sum = 0;
		String negativesNumebrs = "";
		for (int i = 0; i < numbers.length; i++){
			String value = numbers[i].trim();
			if(Integer.parseInt(value) < 0)
				negativesNumebrs += value+",";
				sum += Integer.parseInt(value);
			}
		if(!negativesNumebrs.equals(""))
			throw new IllegalArgumentException("Não é permitido números negativos: " + negativesNumebrs.substring(0, negativesNumebrs.length()-1).trim());
		return sum;
	}
	
	private static boolean isMultipeNumbers(String[] numbers) {
		return numbers.length > 1;
	}

}