Chapter 6. The Life Cycle of a Domain Object Flashcards
___________ mark off the scope within which ________ have to be maintained at every stage of the life cycle.
Aggregates
invariants
DDD, p. 124
Factories and repositories operate on ________, encapsulating the complexity of specific _________.
aggregates
life cycle transitions
DDD, p. 124
With many users consulting and updating different objects in the system, we have to prevent _________ to interdependent objects
simultaneous changes
DDD, p. 126
An aggregate is a ________ of associated objects that we treat as a unit for the purposes of __________
cluster
data changes
DDD, p. 126
Each aggregate has a ________ and a _______.
root
boundary
DDD, p. 126
The __________ defines what is inside the aggregate.
boundary
DDD, p. 126
The root is a ________, _________ contained in the aggregate.
single, specific entity
DDD, p. 126-7
The root is the only member of the aggregate that _________ are allowed to __________.
outside objects
hold reference to
DDD, p, 127
Objects within the boundary may ________ to each other
hold references to
DDD, p. 127
In an aggregate, entities other than the root have a ______ identity.
local
DDD, p. 127
Invariants are ________ rules that must be maintained whenever data ________.
Consistency
Changes
DDD, p. 128
Any rule that _______ aggregates will not be expected to be _______ at all times.
spans
up-to-date
DDD, p. 128
The ______ applied within an aggregate will be _________ with the ________ of each transaction.
invariants
enforced
completion
DDD, p. 128
In the DDD UML models, invariants are indicated by: __________
rules within { }
e.g., {mileage = sum(Position.mileage)}
DDD, p.1 28
The root entity has a _______ identity and is ultimately responsible for checking _________.
global
invariants
DDD, p. 128
The root may hand a _______ of a value object to another object.
copy
DDD, p. 129
Only ______ can be obtained directly with database queries. All other objects must be found by __________.
aggregate roots
Traversal of associations
DDD, p. 129
Objects within the aggregate can hold reference to other __________.
aggregate roots
DDD, p. 129
A ______ operation much remove everything within the aggregate boundary ________.
delete
at once
DDD, p. 129
When a change to ________ with the Aggregate boundary is committed, all __________ of the whole Aggregate ___________.
any object
all invariants
must be satisfied.
DDD, p. 129
Factories provide _______ when the creation of an object or aggregate become complicated or reveals too much of the internal structure.
encapsulation
DDD, p. 136
A program element whose responsibility is the creation of other objects is called a ______.
factory
DDD, p.138
Complex object creation is a responsibility of the ________ layer, yet that task does not belong to the objects that express the _______.
domain
model
DDD, p. 137
One requirement for a good factory is that each creation method is _______ and enforces all ______ of the created object or aggregate.
atomic
invariants
DDD, p. 139
One requirement for a good factory is that the factory should be abstracted to the _______, rather than the concrete class(es) created
type desired
DDD, p. 139
If you need to add elements inside a preexisting aggregate, you might create factor method here…
on the root of the aggregate.
DDD, p. 139
A factory should be attached only to an object that has a _______ relationship with the product.
close natural
DDD, p. 141
A factory method can be put on an object that is closely involved in spawning another object, although it doesn’t _____ the product once it is created.
own
DDD, p. 139
Gamma (1995) talks about three special purpose creation patterns….
Factory Method
Abstract Factory
Builder
DDD, p. 139
When there doesn’t seem to be a natural host for a implementation, we must create a ______ factory object or service.
dedicated
DDD, p.
