protected void accept(JobSpecification jobSpec) {
		T context = preJobSpecWalk();
		JobNode jn = jobSpec.getJobNode();
		if (jn != null) {
			context = walk(context, jn);
		}
		postJobSpecWalk(context, jobSpec);
	}
Called to start a visit of a specific JobSpec.
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/job/dsl/JobSpecificationVisitor.java