@Override
	public String stringify(boolean includePositionInfo) {
		StringBuilder s = new StringBuilder();
		for (int i = 0; i < series.size(); i++) {
			if (i > 0) {
				s.append(" ").append(TokenKind.DOUBLE_PIPE.getTokenString()).append(" ");
			}
			s.append(series.get(i).stringify(includePositionInfo));
		}
		return s.toString();
	}
The AST node representing a flow. A flow is a series of jobs to execute sequentially. Those jobs
can themselves be individual jobs or splits. In DSL form a flow is expressed like this:
<pre><tt>aa || bb</tt></pre>.

@author Andy Clement
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/job/dsl/Flow.java