Bài giảng "Lập trình hướng đối tượng - Chương 4: Sơ đồ tương tác" cung cấp cho người đọc các kiến thức: Interaction Diagrams, a First Look at Sequence Diagrams, Synchronous Messages, Lost Message,... Mời các bạn cùng tham khảo nội dung chi tiết.
AMBIENT/
Chủ đề:
Nội dung Text: Bài giảng Lập trình hướng đối tượng: Chương 4 - TS. Trương Quốc Định
- Chương 4 : Sơ đồ tương tác
GV : TS. Trương Quốc Định
- Interaction Diagrams
A series of diagrams describing the dynamic behavior of
an objectoriented system.
A set of messages exchanged among a set of objects within a
context to accomplish a purpose.
Often used to model the way a use case is realized through a
sequence of messages between objects.
2 Sequence Diagrams
- Interaction Diagrams (Cont.)
The purpose of Interaction diagrams is to:
Model interactions between objects
Assist in understanding how a system (a use case) actually
works
Verify that a use case description can be supported by the
existing classes
Identify responsibilities/operations and assign them to classes
3 Sequence Diagrams
- Interaction Diagrams (Cont.)
UML
Collaboration Diagrams
Emphasizes structural relations between objects
Sequence Diagram
The subject of this tutorial
4 Sequence Diagrams
- A First Look at Sequence Diagrams
Illustrates how objects interacts with each other.
Emphasizes time ordering of messages.
Can model simple sequential flow, branching, iteration,
recursion and concurrency.
5 Sequence Diagrams
- Object
Object naming:
syntax: [instanceName][:className]
myBirthday
Name classes consistently with your class diagram :Date
(same classes).
Include instance names when objects are referred to
in messages or when several objects of the same
type exist in the diagram.
The LifeLine represents the object’s life
during the interaction
Lifelines are drawn as a box with a dashed line
descending from the center of the bottom edge.
The lifeline's name is placed inside the box.
6 Sequence Diagrams
- Messages
An interaction between two objects is performed as a
message sent from one object to another (simple
operation call, Signaling, …)
If object obj1 sends a message to another object obj2
some link must exist between those two objects
7 Sequence Diagrams
- Messages (Cont.)
A message is represented by an arrow between the life
lines of two objects.
Self calls are also allowed
The time required by the receiver object to process the
message is denoted by an activationbox.
A message is labeled at minimum with the message
name.
Arguments and control information (conditions, iteration)
may be included.
8 Sequence Diagrams
- Return Values
Optionally indicated using a dashed arrow with a label
indicating the return value.
Don’t model a return value when it is obvious what is being
returned, e.g. getTotal()
Prefer modeling return values as part of a method invocation,
e.g. ok = isValid()
Model a return value when you need to refer to it elsewhere,
e.g. as a parameter passed in another message.
9 Sequence Diagrams
- Synchronous Messages
Nested flow of control, typically implemented as an
operation call.
The routine that handles the message is completed before the
caller resumes execution.
:A :B
doYouUnderstand()
return
Caller
yes (optional
Blocked
)
10 Sequence Diagrams
- Asynchronous Messages
If a caller sends an asynchronous message, it can continue
processing and doesn’t have to wait for a response.
We can see asynchronous calls in multithreaded
applications and in messageoriented middleware.
Asynchrony gives better responsiveness and reduces the
temporal coupling but is harder to debug.
11 Sequence Diagrams
- Object Destruction
An object may destroy another object via a
message.
An object may destroy itself.
Avoid modeling object destruction unless memory
management is critical.
:A :B
12 Sequence Diagrams
- Found Message
A found message is a message where the receiving event
occurrence is known, but there is no (known) sending
event occurrence.
We interpret this to be because the origin of the message
is outside the scope of the description. This may for
example be noise or other activity that we do not want to
describe in detail.
- Lost Message
A lost message is a message where the sending event
occurrence is known, but there is no receiving event
occurrence.
We interpret this to be because the message never reached
its destination.
- Self Message
A message defines a particular communication between
Lifelines of an Interaction.
Self message is a kind of message that represents the
invocation of message of the same lifeline.
- Recursive Message
A message defines a particular communication between
Lifelines of an Interaction.
Recursive message is a kind of message that represents the
invocation of message of the same lifeline. It's target
points to an activation on top of the activation where the
message was invoked from.
- Object state and Constraint
Sequence diagrams can show how an object changes state
overtime.
We do this by placing the object state on the lifeline at the
appropriate point. This allows we to see very clearly
which events give rise to state changes.
- Object state and Constraint (cont.)
- Object state and Constraint (cont.)
The message acceptPayment(…) causes a state transition
on the :Order object from state unpaid to paid.
The message deliver( ) sent from the :DeliveryManager
object to the :Order object causes a state transition in
:Order from state paid to delivered.
The timing constraint says that there must be 28 days or
less between time A and time B. Time A marks the point
at which the :Order object undergoes transition into the
state paid, and time B marks the point at which the :Order
object undergoes transition into the state delivered.
- Combined Fragment
Combined fragment is an interaction fragment which
defines a combination (expression) of interaction
fragments. A combined fragment is defined by an
interaction operator and corresponding interaction
operands. Through the use of combined fragments the
user will be able to describe a number of traces in a
compact and concise manner.
Thêm vào BST
Báo xấu
Download
Vui lòng tải xuống để xem tài liệu đầy đủ
