private String tokenToString(Token token) {
		return token.stringValue() == null ? new String(token.kind.tokenChars)
				: token.stringValue();
	}
Parse a job flow definition into an abstract syntax tree (AST).

@param jobSpecification the textual job specification
@return the AST for the parsed job
@throws JobSpecificationException if any problems occur during parsing
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/job/dsl/JobParser.java