In JBPM, the relationship between the objects is managed by the rellationmgr. It is used to manage our use because it implements a multi-level two-way management mode. We look at its specific implementation principle:
1) RelationMgr is the interface provided by this management mode, which is mainly dealing with this class;
2) RelationMgr references the ReferenceMgr object, which is implemented by this object.
3) ReferenceMgr is an interface that there are two implementations: CollectionMgr and Propertymgr, formerly manage 1 to more relationships, the latter management one-on-one (multi-one is a one-on-one unified process) relationship
4) CollectionMgr has a sub-class as MAPMGR to handle our common MAP relationships
5) PropertyMGR has a sub-class as indexedPropertyMgr, which is handled in Index.
6) ReferenceMgr is mainly to implement specific features via PropertyAccessor, the latter stores a field with an object, and provides a method of removing a field from a certain field.
It can be seen that JBPM is very clever use inheritance and reference, and concisely realizes the two-way object management mode.
