db4o

ObjectContainer.get Method 

Query-By-Example interface to retrieve objects.

[Visual Basic]
Function get( _ 
   ByVal template As Object _ 
) As ObjectSet
[C#]
ObjectSet get(
   object template
);
[C++]
ObjectSet* get(
   Object* template
);
[JScript]
function get(
   Object template
): ObjectSet;

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 Evaluation
All 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 activation depth 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 | Why activation? | Using callbacks