Architecture Design

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The architecture design of the system will have a large impact on the system's ability to fulfill both functional and non-functional requirements. The correct design patterns, mechanisms, and technology must be specified in the design of the architecture.

The architecture can be modeled using a variety of different models. This page will provide examples of the following architectural model diagrams:

Structural View Model

Returning to the microwave oven example, the following structural view model diagram provides a structural view of the system under development:
Structural View of Architecture Diagram PNG

Data Dictionary:

Every diagram needs to have a data dictionary as supporting documentation. The data dictionary cleary explains the entities that are depicted in the diagram. The data dictionary for the above diagram follows:

Term

Description

Type

Requirements Trace

Auto Cook Presets

Processes input data containing manufacturer-defined presets for heating common food items.

Sub-system

F4.3.1, F4.3.2, F4.3.3

Auto Defrost

Processes input data containing power level and time for defrosting frozen food item.

Sub-system

F4.4.1, F4.4.2, F4.4.3, F4.4.4, F4.4.5, F4.4.6

Beeper

Processes output signals to the beeper device.

Sub-system

F4.2.5, F4.5.8, F4.5.10, F4.5.11

Clock

Processes input data containing clock-setting parameters.

Sub-system

F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9

Command Processing

Processes all inputs from the user.

System

F4, F5

Cooking Control

Processes output data from Command Processing System and sends command signals to the Oven Control sub-system.

Sub-system

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.8, F4.5.9, F4.5.11, F4.5.12

Display Power

Processes output data containing the current power level that is encoded for display on the LCD.

Sub-system

F4.3.2, F4.3.3, F4.4.1, F4.4.2, F4.5.1, F4.5.2

Display Time

Processes output data containing the current time of day value that is encoded for display on the LCD.

Sub-system

F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9

Monitor / Process Inputs

Processes pre-processed inputs and controls system state based on those inputs.

Sub-system

F1, F2, F3, F4, F5, F6

Output Processing

Processes output data and converts it to signals and codes that can be used by the target output devices.

System

F1, F2, F4.1.4, F4.1.7, F4.1.8, F4.1.9, F4.2.5, F4.2.6, F4.2.7, F4.2.9, F4.3.3, F4.4.3, F4.4.5, F4.5.5, F4.5.7, F4.5.8, F4.5.10, F4.5.11, F5, F6

Oven Control (sub-system)

Processes data sent from the Cooking Control sub-system and converts the data into the correct format for the cooker component.

Sub-system

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.8, F4.5.9, F4.5.11, F4.5.12

Oven Control (system)

Processes output data and converts it to signals that can be used by the cooker component.

System

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.8, F4.5.9, F4.5.11, F4.5.12

Deployment View Model

UML provides a similar model called a deployment view model. A deployment view model is part of the deployment view of the system. A deployment view may also be referred to as an allocation view. The deployment view model diagram for the microwave oven example follows:
Deployment Diagram PNG

The process monitor component and the hardware signal handler component work together to fulfill non-functional requirement N9. The hardware signal handler will capture power tolerance errors from sent from the hardware sensors and will convey them to the process monitor so that the system can handle the error appropriately by displaying the error to the user via the LCD screen. The hardware signal handler is a multi-purpose component in that it reports various types of hardware signals including signals from the microwave door latch sensor.

Data Dictionary:

Term

Description

Type

Requirements Trace

Beeper Driver

Generates output signals to the beeper device.

Sub-component

F4.2.5, F4.5.8, F4.5.10, F4.5.11

Command Processor

Processes commands entered by the user and controls the oven devices according to the command given within the constraints of the current state of the system.

Sub-component

F4.1.3, F4.1.5, F4.1.6, F4.2.1, F4.2.3, F4.2.4, F4.2.7, F4.2.8, F4.2.9, F4.3.3, F4.4.4, F4.4.6, F4.5.1, F4.5.3, F4.5.6, F4.5.7, F4.5.9, F4.5.10

Controller

Processes system inputs and controls system state based on those inputs.

Component

F1, F2, F3, F4, F5, F6

Cooker Driver

Generates output signals to the cooker device.

Sub-component

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.8, F4.5.9, F4.5.11, F4.5.12

Hardware Signal Handler

Handles input signals from hardware components and sends correctly formatted data to the Controller.

Sub-component

F1, F2, F4.5.8, F4.5.9, F6

Input Handler

Handles input data from the keypad as well as from oven components such as the cooker component and the door latch sensor.

Component

F1, F2, F3, F4, F5, F6

Keypad Driver

Handles all inputs from the keypad.

Sub-component

F1, F4.1.1, F4.1.5, F4.1.6, F4.2.1, F4.2.3, F4.2.4, F4.2.7, F4.2.8, F4.2.9, F4.3.2, F4.3.3, F4.4.5, F4.4.6, F4.5.1, F4.5.3, F4.5.6, F4.5.7, F4.5.9, F4.5.10

LCD Driver

Generates output signals to the cooker device.

Sub-component

F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.3.2, F4.3.3, F4.4.1, F4.4.2, F4.5.1, F4.5.2

Output Processor

Generates output data and converts it to signals and codes that can be used by the beeper and LCD output devices.

Component

F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.2.5, F4.3.2, F4.3.3, F4.4.1, F4.4.2, F4.5.1, F4.5.2, F4.5.8, F4.5.10, F4.5.11

Oven Controller

Processes output data and converts it to signals that can be used by the cooker component.

Component

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.8, F4.5.9, F4.5.11, F4.5.12

Process Monitor

Processes signals from hardware components, monitors the status of other system components, and controls the oven devices according the current state of the system.

Sub-component

F1, F2, F3, F4, F5, F6

Data View Model

A data view is the same diagram as the structural view, but with annotations that are specific to the flow of data between the components. The data view model diagram of the architecture for the microwave oven example follows:
Architecture Data View Diagram PNG

Data Dictionary:

(Same as for Structural View Model above.)

Layered View Model

UML provides an architectural model called a layered model that specifies a hierarchy of dependency relationships. A layered model is a type of module view and UML utilizes package entities as layers using a dependency relationship (dashed arrow) between each of the layers. The dependency relationships indicate that a given layer can depend on layers that are lower than that layer, but cannot depend on layers that are above that layer. Such a layer model may also be referred to as an "architectural brick". A layered model diagram for the microwave oven example follows:
Microwave Layered View Diagram PNG

Having a total of only four layers where of those layers only three of the layers are software layers help to fulfill non-functional requirement N8.

Data Dictionary:

(Same as for Deployment View Model above.)

Object-oriented Decomposition View Model

Object-oriented Decomposition View Diagram PNG

Data Dictionary:

Term

Description

Type

Requirements Trace

Accepts Cooking-desc Data

Oven Control System operation that accepts cooking data.

Method

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.9, F4.5.10

Accepts DoorStatus Data

Command Processing System (Controller) operation that accepts data from the door sensor.

Method

F2, F4.2.10, F4.5.8, F4.5.9

Accepts Keypad Data

Command Processing System (Controller) operation that accepts keycode data from the keypad.

Method

F1, F4

Accepts Process Desc

Output Processing System operation that accepts process-related data.

Method

F3, F4, F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.2.1, F4.2.6, F4.2.7, F4.3.1, F4.3.3, F4.4.1, F4.4.2, F4.4.3, F4.4.4, F4.4.5, F4.4.6, F4.5.5, F4.5.7, F4.5.8, F5, F6

Action

Keypad action key.

Attribute

F1, F4

Beeper

Beeper entity that encapsulates beeper attributes.

Class

F1, F2, F4.2.5, F4.2.9, F4.5.8, F4.5.10, F4.5.11

Clock / Timer

Clock and Timer attributes of the Display entity.

Attribute

F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.2.1, F4.2.6, F4.2.7

Closed

Status attribute of the Door class.

Attribute

F2, F4.2.10, F4.5.8, F4.5.9

Command Processing System

Controller entity that encapsulates controller object attributes and operations.

Class

F4, F4.3.1, F4.3.2, F4.4.2, F4.4.5, F4.4.6

Cooking Function Data

Oven Control System attribute that identifies the cooking function selected.

Attribute

F5

Cooking Process Desc

Output Processing System attribute that contains cooking process-related data.

Attribute

F3, F4, F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.2.1, F4.2.6, F4.2.7, F4.3.1, F4.3.3, F4.4.1, F4.4.2, F4.4.3, F4.4.4, F4.4.5, F4.4.6, F4.5.5, F4.5.7, F4.5.8, F5, F6

Display

Display entity that encapsulates display object attributes.

Class

F3, F4, F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.2.1, F4.2.6, F4.2.7, F4.3.1, F4.3.3, F4.4.1, F4.4.2, F4.4.3, F4.4.4, F4.4.5, F4.4.6, F4.5.5, F4.5.7, F4.5.8, F5, F6

Door

Door entity that encapsulates door object attributes.

Class

F2, F4.2.10, F4.5.8, F4.5.9

Door Status Data

Command Processing System (Controller) attribute that contains door status data.

Attribute

F2, F4.2.10, F4.5.8, F4.5.9

Formats Display Info

Output Processing System operation that formats data that will be sent to the display device.

Method

F3, F4, F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.2.1, F4.2.6, F4.2.7, F4.3.1, F4.3.3, F4.4.1, F4.4.2, F4.4.3, F4.4.4, F4.4.5, F4.4.6, F4.5.5, F4.5.7, F4.5.8, F5, F6

Function

Keypad Function key.

Attribute

F1, F4

Function Name

Attribute of the Display entity that contains the name of the selected function.

Attribute

F5

Generator Control

Oven Control System attribute that contains the control codes for the generator.

Attribute

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.9, F4.5.10

Keypad

Keypad entity that encapsulates keypad object attributes.

Class

F1, F4

Keypad Data

Command Processing System (Controller) attribute that contains keycode data from the keypad.

Attribute

F1, F4

Microwave Generator

Microwave Generator (cavity magnetron) entity that encapsulates generator object attributes.

Class

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.9, F4.5.10

Numeric

Keypad Numeric key.

Attribute

F1, F4

On/Off

Microwave Generator class attribute that contains the current status of the generator.

Attribute

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.9, F4.5.10

Open

Status attribute of the Door class.

Attribute

F2, F4.2.10, F4.5.8, F4.5.9

Output Processing System

Output Processing System entity that encapsulates output processing system object attributes and operations.

Class

F3, F4, F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.2.1, F4.2.6, F4.2.7, F4.3.1, F4.3.3, F4.4.1, F4.4.2, F4.4.3, F4.4.4, F4.4.5, F4.4.6, F4.5.5, F4.5.7, F4.5.8, F5, F6

Power Level

Microwave Generator class attribute that contains the current power level of the generator.

Attribute

F4.3.1, F4.3.2, F4.4.1, F4.4.2, F4.4.3, F4.4.6, F4.5.1, F4.5.2, F4.5.10, F4.5.12

Power Level

Attribute of the Display entity that contains the power level selected by the user.

Attribute

F4.3.1, F4.3.2, F4.4.1, F4.4.2, F4.4.3, F4.4.6, F4.5.1, F4.5.2, F4.5.10, F4.5.12

Presets

Keypad Preset key.

Attribute

F1, F4, F4.3.1, F4.3.2, F4.3.3

Processes Data

Command Processing System (Controller) operation that processes input data.

Method

F2, F4.2.10, F4.5.8, F4.5.9

Processes Desc Data

Output Processing System operation that processes descripton data.

Method

F3, F4, F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.2.1, F4.2.6, F4.2.7, F4.3.1, F4.3.3, F4.4.1, F4.4.2, F4.4.3, F4.4.4, F4.4.5, F4.4.6, F4.5.5, F4.5.7, F4.5.8, F5, F6

Prompt

Attribute of the Display entity that contains the prompt data to be displayed.

Attribute

F4.4.1, F4.4.5

Sends Beeper Signal

Output Processing System operation that sends signals to the beeper device.

Method

F1, F2, F4.2.5, F4.2.9, F4.5.8, F4.5.10, F4.5.11

Sends Commands / Data

Command Processing System (Controller) operation that sends commands and data to the necessary components to maintain a valid system state.

Method

F1, F2, F3, F4, F5, F6

Sends Display Data

Output Processing System operation that sends signals to the display device.

Method

F3, F4, F4.1.1, F4.1.2, F4.1.3, F4.1.4, F4.1.5, F4.1.6, F4.1.7, F4.1.8, F4.1.9, F4.2.1, F4.2.6, F4.2.7, F4.3.1, F4.3.3, F4.4.1, F4.4.2, F4.4.3, F4.4.4, F4.4.5, F4.4.6, F4.5.5, F4.5.7, F4.5.8, F5, F6

Sends Generator control Data

Oven Control System operation that sends the control data / signals to the generator.

Method

F4.3.3, F4.4.6, F4.5.6, F4.5.7, F4.5.9, F4.5.10

Tone Off

Attribute of the Beeper entity that contains the status of the beeper device.

Attribute

F1, F2, F4.2.5, F4.2.9, F4.5.8, F4.5.10, F4.5.11

Tone On

Attribute of the Beeper entity that contains the status of the beeper device.

Attribute

F1, F2, F4.2.5, F4.2.9, F4.5.8, F4.5.10, F4.5.11

Statechart (State Machine) Model

A description of statechart diagrams was given earlier in this software development process on the "Create System Model" page. This section contains an excellent example of a statechart diagram that was re-created from a figure in Ian Sommerville's book, Software Engineering (This text is referenced on the "References" page of this website). The following statechart diagram models the cooking operation of a microwave oven using simple and composite states.
Cook Operation Statechart Diagram PNG

Data Dictionary:

The information contained in the following data dictionary tables was taken verbatim from Ian Sommerville's book, Software Engineering (This text is referenced on the "References" page of this website).

State

Description

Waiting

The oven is waiting for input. The display shows the current time.

Half power

The oven power is set to 300 watts. The display shows ‘Half power’.

Full power

The oven power is set to 600 watts. The display shows ‘Full power’.

Set time

The cooking time is set to the user’s input value. The display shows the cooking time selected and is updated as the time is set.

Disabled

Oven operation is disabled for safety. Interior oven light is on. Display shows ‘Not ready’.

Enabled

Oven operation is enabled. Interior oven light is off. Display shows ‘Ready to cook’.

Operation

Oven in operation. Interior oven light is on. Display shows the timer countdown. On completion of cooking, the buzzer is sounded for 5 seconds. Oven light is on. Display shows ‘Cooking complete’ while buzzer is sounding.

Stimulus

Description

Half power

The user has pressed the half power button

Full power

The user has pressed the full power button

Timer

The user has pressed one of the timer buttons

Number

The user has pressed a numeric key

Door open

The oven door switch is not closed

Door closed

The oven door switch is closed

Start

The user has pressed the start button

Cancel

The user has pressed the cancel button


Now that we have completed the design of the architecture by modeling the basic structure of the microwave oven system, we can begin design of the system interfaces.

Note: This is clearly an abridged architectural design to make the content suitable for an instructional web page. It would make sense to have a more elaborate architectural design for a real project.

No part of this work should be produced or used without the permission of the authors: Michael Turner and Dr. Sharon A White.