Spring Data Neo4j - Neo4j in Action - page 225

Both the @RelatedTo and @RelatedToVia and annotations can take
a type and optional direction element, specified to clarify whether relationships of
a particular direction (valid values are INCOMING , BOTH , and the default OUTGOING )
should be included in the collection of entities returned.
Note that for the friends property you need to specify the direction as BOTH , as shown
in the following snippet:
@RelatedTo(type = "IS_FRIEND_OF", direction = Direction.BOTH)
Set<User> friends;
Logically, a friends relationship is bidirectional; physically within Neo4j, however, re-
lationships are only stored in one direction. By specifying BOTH , you're telling Neo4j to
consider any IS_FRIENDS_OF relationships associated with the user, regardless of the
direction in which the physical relationship is defined.
9.3. Accessing and persisting entities
You've seen how you can use annotations to provide SDN with the basic information it
needstomapyourPOJOclasses totheunderlyinggraph-backed database without somuch
as a low-level node or relationship class in sight. This is a great step forward in having to
only deal with business-level concepts in your domain model code. The next logical ques-
tions are how you can interact with these entities and how you can load and save your
POJO entities to and from the graph database.
SDN offers a few options in this area, and we'll be focusing on two of them in this section,
namely the Neo4jTemplate class and the more general concept of Spring data repos-
itories. Before that, we'll look at the supporting Spring configuration, which you need to
supply in order to make this all work.
9.3.1. Supporting Spring configuration
The following listing shows the minimum XML Spring configuration required to initialize
SDN so it can find your domain entities and make various beans (such as the Neo4jTem-
plate ) available to you.