How to Apply the GRASP Patterns?
The following sections present the first five GRASP patterns:
. Information Expert
. Creator
. High Cohesion
. Low Coupling
. Controller
Package diag:
UML package diagrams are often used to illustrate the logical
architecture of a system-the layers, subsystems, packages . A layer
can be modeled as a UML package; It is part of the Design Model and
also be summarized as a view in the Software Architecture
Document.
TESTING:
Testing is a method to check whether the actual software product
matches expected requirements and to ensure that software product
is Defect free. It involves execution of software/system components
using manual or automated tools to evaluate one or more properties
of interest. The purpose of software testing is to identify errors, gaps
or missing requirements in contrast to actual requirements.
Some prefer saying Software testing definition as a White
Box and Black Box Testing.
TEST PLAN:
A Test Plan is a detailed document that describes the test strategy,
objectives, schedule, estimation, deliverables, and resources
required to perform testing for a software product. Test Plan helps
us determine the effort needed to validate the quality of the
application under test. The test plan serves as a blueprint to conduct
software testing activities as a defined process, which is minutely
monitored and controlled by the test manager.
LAYERS OF PACKAGE DIAGRAM:
User Interface – Has various I/O formats & forms.
Application Logic and Domain Objects - software objects
representing domain concepts (for example, a software class Sale)
that fulfill application requirements, such as calculating a sale total.
Technical Services general purpose objects and subsystems that
provide supporting technical services, such as interfacing with a
database or error logging.
REFACTORING:
Refactoring is the process of restructuring code, while not
changing its original functionality. The goal of refactoring is to
improve internal code by making many small changes without
altering the code's external behavior.
Computer programmers and software developers refactor code
to improve the design, structure and implementation of
software. Refactoring improves code readability and reduces
complexities. Refactoring can also help software developers
find bugs or vulnerabilities hidden in their software.
Deployment Diagrams
A deployment diagram shows the assignment of concrete
software artifacts (such as executable files) to computational
nodes (something with processing services). It shows the
deployment of software elements to the physical architecture
and the communication (usually on a network) between
physical elements
Two Nodes of Deployment Diagram :
Device Node :This is a Physical Computing Resource
representing a computer with memory or mobile.
Execution Environment Node :
This is a software computing resource that runs within an
outer node (such as a computer) and which itself provides a
service to host and execute other executable software
elements
ADV OF MODELING STATE MACHINE DIAGRAM:
State machines are useful modeling aids for developing realtime or event-driven systems because they show dynamic
behavior. You can develop state machines during all phases of
a software project and for business modeling. You can use
state machines in the following situations:



During business modeling, you can create state machines to
model a use-case scenario.
During analysis and design, you can model event-driven
objects that react to events outside an object's context.
During analysis and design, you can use several state
machine diagrams to show different aspects of the same
state machine and its behavior.
Testing
Debugging
Testing is the process to
find bugs and errors.
Debugging is the process to
correct the bugs found during
Testing
Debugging
testing.
It is the process to identify
the failure of implemented
code.
It is the process to give the
absolution to code failure.
Testing is the display of
errors.
Debugging is a deductive
process.
Testing is done by the
tester.
Debugging is done by either
programmer or developer.
There is no need of design
knowledge in the testing
process.
Debugging can’t be done
without proper design
knowledge.
Testing can be done by
insider as well as outsider.
Debugging is done only by
insider. Outsider can’t do
debugging.
Testing can be manual or
automated.
Debugging is always manual.
Debugging can’t be automated.
It is based on different
testing levels i.e. unit
testing, integration testing,
system testing etc.
Debugging is based on
different types of bugs.
Testing is a stage of
software development life
cycle (SDLC).
Debugging is not an aspect of
software development life
cycle, it occurs as a
consequence of testing.
Testing
Debugging
Testing is composed of
validation and verification
of software.
While debugging process
seeks to match symptom with
cause, by that it leads to the
error correction.
Testing is initiated after the
code is written.
Debugging commences with
the execution of a test case.
Testing process based on
various levels of testingsystem testing, integration
testing, unit testing, etc.
Debugging process based on
various types of bugs is
present in a system.
Generalize your views about inception in use case
Inception Phase - During the inception phase the core idea is developed into a product
vision. In this phase, we review and confirm our understanding of the core business drivers. We
want to understand the business case for why the project should be attempted.
Analyze the concepts of Noun Phase Identification from use
case
Identifying Tentative classes. 2. Selecting classes from the Relevant and fuzzy categories. 3. The
vialNet Bank ATM System: Identifying classes by using Noun phrase Approach. 4. Initial List of Noun
phrases: candidate classes. 5. Reviewing the Redundant classes and Building a common vocabulary
Write the criteria in planning the next iteration during elaboration
phase
The elaboration phase is meant to clarify these qualities and reach a consensus. Simply put, it
makes our collaboration more productive and eliminates any misunderstandings. As a
result, customers can understand how much the product will cost and how soon it will be
completed.
Difference between sequence and use case diagram
Usecase diagram
----------------Use case diagrams show business use cases, actors, and the relationships between
them. The relationships between actors and business use cases state that an actor
can use a certain functionality of the business system. You will not find any
information about
ut how or in what chronological sequence these services are
rendered
sequence diagram
-----------------A sequence diagram can map a scenarios described by a use case in step by step
detail to define how objects collaborate to achieve your application's goals.
Example of Domain
omain model with uml class diagram notation
Primary goal in design of uml
The primary goal of UML is to define some general-purpose
purpose simple modeling
language so that all modelers can use and understan
understand.. UML is not a
development method rather it accompanies with processes to make a successful
system.
Test can help to find useful use cases
Use case testing is a technique that helps to identify test cases that cover the entire
system, on a transaction by transaction basis, from start to finish. It is a description of a
particular use of the system by a user. It is used widely in developing tests or systems for
acceptable levels
Probable attributes for Library database object book
An attribute is a piece of information about the entity. For example, the title, author, and
ISBN are all attributes of a book entity.
Purpose of using use cases
Use cases add value because they help explain how the system should behave and in the
process, they also help brainstorm what could go wrong. They provide a list of goals and
this list can be used to establish the cost and complexity of the system.
Fully dressed and casual use cases in the nextgen inception phase
Fully Dressed
Process Sale Handle Returns
Casual
Process Rental
Analyze Sales Activity
Manage Security
Classifier
A classifier is an abstract metaclass classification concept that serves as a mechanism to
show interfaces, classes, datatypes and components. A classifier describes a set of
instances that have common behavioral and structural features (operations and attributes,
respectively).
Compare coupling and cohension
Cohesion
Coupling
Cohesion is the concept of intra-module. Coupling is the concept of inter-module.
Cohesion represents the relationship
within a module.
Increasing cohesion is good for software.
Cohesion represents the functional
strength of modules.
Coupling represents the relationships
between modules.
Increasing coupling is avoided for software.
Coupling represents the independence
among modules.
Whereas loosely coupling gives the best
Highly cohesive gives the best software. software.
In cohesion, the module focuses on a
In coupling, modules are connected to the
single thing.
other modules.
Cohesion is created between the same Coupling is created between two different
module.
modules.
There are Six types of Cohesion
There are Six types of Coupling
1.
2.
3.
4.
5.
6.
Functional Cohesion.
Procedural Cohesion.
Temporal Cohesion.
Sequential Cohesion.
Layer Cohesion.
Communication Cohesion.
1. Common Coupling.
2. External Coupling.
3. Control Coupling.
4. Stamp Coupling.
5. Data Coupling
6. Content Coupling
When to use package and collaboration diagram
Packages are particularly useful for testing. Although I do write some tests on a classby-class basis, I prefer to do my unit testing on a package-by-package basis. Each
package should have one or more test classes that test the behavior of the package.
collaborations are useful whenever you want to refer to a particular interaction.
Parameterized collaborations are useful when you have several similar collaborations in
your system.
aggregation
Aggregation is a subset of association, is a collection of different things. It represents
has a relationship. It is more specific than an association. It describes a part-whole or
part-of relationship. It is a binary association, i.e., it only involves two classes. It is a
kind of relationship in which the child is independent of its parent.
When can we use pattern
when you are working through a design, and particular part of a system
requires something that fits a design pattern you have, then use it. Don't try to fit
a system round a design pattern, fit design patterns in to your system (where they
fit).