@Override
	public String toString() {
		StringBuilder s = new StringBuilder();
		s.append(tokenStream).append("\n");
		s.append(expression).append("\n");
		Token t = tokenStream.get(position);
		int i = 0;
		for (; i < t.startpos; i++) {
			s.append(" ");
		}
		for (; i < t.endpos; i++) {
			s.append("^");
		}
		s.append("\n");
		return s.toString();
	}
Throw a new {@link CheckpointedJobDefinitionException} based on the current and
last successfully processed token position.

@param position position where parse error occurred
@param message  parse exception message
@param inserts  variables that may be inserted in the error message
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/job/dsl/Tokens.java