1. Logical Architecture & UML Package Diagrams

2. Let’s take a step back Why is it so difficult to build good software?
bugs/?currentPage=all

3. The “60’s Software crisis”
Moved from HW to SW demand
Product complexity growth
Demand of SW in NASA & Boeing increased exponentially
Development effort
Class exercise
Small project
Term project
Word processor
Operating system
Developers productivity growth - gap between that and the software complexity needed
Davis /7 million spent were wasted (not used or not delivered software)
Nato 1969 conference on software development
realization that you cannot build exactly the software you need

4. Software Process Break down complexity in a systematic way
Break it down in a formal way
Processes:
Waterfall - the way the water falls
Evolutionary prototyping
Rational Unified Process
Agile - sacrifice discipline to accommodate changes, more usually changes in requirements

5. Software Phases Requirements engineering
Design - high level structure of sw
Implementation - code
Verification and validation
Maintenance - bugs, new functionality
SW Phases: only one related to coding

6. Software Tools Progression
Development: Punch cards to IDES
Language: Assembly to high level
Debugging: Print lines to symbolic debuggers
Git
Coverage and verification tools

7. Preliminary Iteration(s)
The UP Disciplines
Management
Environment
Business Modeling
Implementation
Test
Analysis & Design
Preliminary Iteration(s)
Iter. #1
Phases
Process Disciplines
Iterations
Iter. #2
Iter. #n
Iter. #n+1
Iter. #n+2
Iter. #m
Iter. #m+1
Deployment
Configuration Mgmt
Requirements
Elaboration
Transition
Inception
Construction
Supporting Disciplines
In an iteration you
walk through all
disciplines.

8. Preliminary Iteration(s)
The UP Disciplines
Management
Environment
Business Modeling
Implementation
Test
Analysis & Design
Preliminary Iteration(s)
Iter. #1
Phases
Process Disciplines
Iterations
Iter. #2
Iter. #n
Iter. #n+1
Iter. #n+2
Iter. #m
Iter. #m+1
Deployment
Configuration Mgmt
Requirements
Elaboration
Transition
Inception
Construction
Supporting Disciplines
Focus of this
course.
Although an iteration includes work in most disciplines, the relative effort and emphasis change over time.
Early iterations tend to apply greater emphasis to requirements and design, and later ones less so.
Figure illustrations are suggestive, not literal.
Note that activities and artifacts are optional (except code!)
Developers select those artifacts that address their particular needs.

9. What is this architecture thing again?
Software Architecture deals with the large scale system
Software architecture includes
organization and major structure of the major elements of the system
system and subsystem behavior
collaborations
Architectural investigation
Identifying those functional and non-functional requirements that should have a significant impact on the system design
Architectural design
Resolution of requirements in the design of the software, the hardware and networking, etc.
Architectural Dimensions and Views in UP
Logical Architecture – conceptual organization of system in layers, packages, major frameworks, classes, interfaces, subsystems
Deployment Architecture – allocation of processes to processing units and network configuration

10. Logical Architecture (LA) part of Design Model
Logical architecture: the large-scale organization of software classes into packages, subsystems, and layers. “Logical” because no decisions about how these elements are deployed across different operating system processes or across physical computers in a network 
Logical architecture is a structural design that gives as much detail as possible without constraining the architecture to a particular technology or environment. For example, a diagram that illustrates the relationship between software components.
Physical architecture gives enough detail to implement the architecture on a technology. For example, a specification of software services and components.

11. UML Package Diagrams & Layers
What is LA? Large-scale organization of the sw classes into packages or namespaces, subsystems, & layers
Logical: no decision how to deploy elements, vs deployment architecture
What is a layer? Very coarse grained grouping of classes, packages, subsystems, that has cohesive responsibility for a major aspect of the system
What is SW architecture?? An architecture is the set of significant decisions about the organization of a sw system. Selection of structural elements, system components, behavior and collaborations. Has to do with large scale Big Ideas in motivations, constraints, organizations, patterns, responsibilities, & connections of system

12. Guideline: Design with Layers
Why design with layers? Separation of concerns, low coupling, relate components with appropriate parts of system.
How many layers?
Architectural Pattern : Layers
Solution
Organize the large-scale logical structure of a system into discrete layers of distinct, related responsibilities, with a clean cohesive separation of concerns such that the “lower” layers are low-level and general services, and the higher layers are more application specific.
Collaboration and coupling is from higher to lower layers; lower to higher layer coupling is avoided
Problems
Source code problems are rippling throughout the system – many parts of the system are highly coupled
Application logic is intertwined with the user interface, and cannot be reused with a different interface, nor distributed to another processing mode
Potential general technical services or business logic is intertwined with more application specific logic.
There is a high coupling across different areas of concern. It is difficult to divide the work along clear boundaries for different developers

13. Common Layers in Information Systems

14. Domain Layer and Domain Model Relationship
How do we design the application logic with Objects?
What is domain model? Visualization of noteworthy domain concepts, inspiration for names of classes
Domain Layer: part of the sw and the domain model

15. Layers & Partitions
Layers: vertical, partitions: horizontal, parallel slices

16. Mixing Views in the Architecture

17. Model-View Separation Principle
do not couple non-UI objects to UI objs
DO NOT put application logic into the UI obj methods Model: domain layer of objects View: UI objects Model objects should not have direct knowledge of view objs. MVC enterItem(…) message from UI layer to Domain Layer

18. References
Packages in java and how to use them:
Chapter 30 – Designing the Logical Architecture Patterns
A package as the name suggests is a pack(group) of classes, interfaces and other packages. In java we use packages to organize our classes and interfaces. We have two types of packages in Java: built-in packages and the packages we can create (also known as user defined package). In this guide we will learn what are packages, what are user-defined packages in java and how to use them.