Mumbai University > Computer Engineering > Sem 7 > Software Architecture

Marks: 10M

Year: Dec 2015

Software Connector

• Connectors in software system implementations

  Frequently no dedicated code

  Frequently no identity

  Typically do not correspond to compilation units

  Distributed implementation

• Across multiple modules

• Across interaction mechanisms
• Perform and regulate interactions between components

• A connector couples two or more components to perform transfers of data and control

• Connectors are a model of static and dynamic aspects of the interaction between component interfaces

• Connectors model interactions between components Connectors are built with (very complex) components

• Connectors are not usually directly visible in the code (e.g., linkage between modules, connections across the network, configurations of server addresses)

Components vs. Connectors

• Components can be mapped to specific code artifacts (e.g., compilation units, deployment packages)
• Connectors are not usually directly visible in the code (e.g., linkage between modules, connections across the network, configurations of server addresses)
• Components can be both application-specific or application-independent (infrastructure)
• Connectors are mostly application-independent

Connectors are Abstractions

• Connectors model interactions between components
• Connectors are built with (very complex) components

Roles

Communication

Coordination

Conversion

Facilitation

Event–Based Connectors

• Event connectors are similar to procedure call connectors in that they model the flow of control among components (communication).
• In this case, the flow is precipitated with an event.
• Messages containing a description of the event can be generated upon the occurrence of a single event or a specific pattern of events.
• The contents of an event message can be structured to contain information about the event and other application specification information (communication).
• An example of this connector type are GUI events. Some events like page fault are caused by hardware.

Distributor:

• Distributed systems require identification of component locations and interaction paths to them based on symbolic names.
• Distributor connector perform the identification of interaction paths and subsequent routing of communication and coordination information among components along these paths (facilitation) Examples are Domain Name Service.
• Connectors define the points of distribution at designtime so that components can be deployed over multiple physical hosts at run-time.

• Connectors allow modeling of arbitrarily complex interactions

• Connector flexibility aids system evolution

  Component addition, removal, replacement, reconnection, migration

• Support for connector interchange is desired Aids system evolution May not affect system functionality

Client Server Style

Summary:

• Client initiates communication by sending server a request.
• Server performs the requested action and replies.

Design elements: • Components: client(s) and server • Connectors: remote procedure call, network protocols • Data: parameters and return values

Topology:

• Two-level, multiple clients making requests to server
• No client-client communication

Examples

Centralization of data is required

Server: high-capacity machine (processing power)

Clients: simple UI tasks

Many business applications − 2IIC0 “Business Information Systems” SfS, WbS:Y3Q1