@Override
	public StreamNode lookupStream(String name) {
		if (this.repository != null) {
			BaseDefinition baseDefinition = repository.findOne(name);
			if (baseDefinition != null) {
				StreamNode streamNode = new StreamConfigParser(repository).parse(baseDefinition.getDefinition());
				return streamNode;
			}
		}
		return null;
	}
Return the concatenation of the data of many tokens.
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/stream/dsl/StreamConfigParser.java