protected Token next() {
		if (!hasNext()) {
			raiseException(expression.length(), JobDSLMessage.OOD);
		}
		return tokenStream.get(position++);
	}
Return the next {@link Token} and advance the current token position.

@return next {@code Token}
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/job/dsl/Tokens.java