ObjectContainer.get Method
Query-By-Example interface to retrieve objects.
Parameters
-
template
- object to be used as an example to find all matching objects.
Return Value
ObjectSet containing all found objects.
Remarks
Query-By-Example interface to retrieve objects.
get()
creates an
ObjectSet containing all objects in the
ObjectContainer
that match the passed template object.
Calling
get(NULL)
returns all objects stored in the
ObjectContainer
.
Query EvaluationAll non-null members of the template object are compared against all stored objects of the same class. Primitive type members are ignored if they are 0 or false respectively.
Arrays and all supported
Collection
classes are evaluated for containment. Differences in
length/size()
are ignored.
Consult the documentation of the Configuration package to configure class-specific behaviour.
Returned Objects The objects returned in the
ObjectSet are instantiated and activated to the preconfigured depth of 5. The
activationDepth may be configured
globally or
individually for classes .
db4o keeps track of all instantiatied objects. Queries will return references to these objects instead of instantiating them a second time.
Objects newly activated by
get()
can respond to the callback method
objectOnActivate .
See Also
ObjectContainer Interface | com.db4o Namespace | activationDepth | Using callbacks