public static int numberOfTrues(boolean... bs) {
		int result = 0;
		for (boolean b : bs) {
			if (b) {
				result++;
			}
		}
		return result;
	}
Return true when 2 or more booleans are true, false otherwise.
spring-xd-module-spi/src/main/java/org/springframework/xd/module/options/validation/Exclusives.java