@Override
			public BaseDefinition findOne(String s) {
				BaseDefinition inMemory = store.get(s);
				return inMemory != null ? inMemory : delegate.repository.findOne(s);
			}
A throwaway repository that is used during multi-definition parsing. "Sees" definitions that are
known to the real {@link #repository} and stores new definitions in an in-memory map.

@author Eric Bottard
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/stream/XDStreamParser.java