Understanding Software Connector Compatibilities

7/28/2019 Understanding Software Connector Compatibilities

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Software ArchitecturesHigh-level modeling primitives

Components, connectors, configurations [SG96]Software connectors To mediate interactions among components

To provide auxiliary mechanisms for interaction Impact aggregate system properties

Liveness, throughput, dependability, evolvability

Support in software architecture techniques Modeling [AG97], middleware support [MMR02]

Complementary approaches

Middleware (ORB), standards (e.g. COM, J2EE)


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Towards Richer ConnectorsFocus on connectors

Component scale, complexity requires greaterdistribution

Complexity of interactions a bigger concern thancomplexity of algorithms

Simple connectors Procedure calls, module dependencies, pipes

Complex connectors DNS, remote procedure calls, repository access

State-of-the-art in software connectors

Model arbitrarily complex - implement simple ones


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Interaction Services (MMP00)Communication

Transmission of data

Coordination

Exchange of controlConversion

Transform interactions to remedy heterogeneity

Facilitation

Streamline interactions for interoperation


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Classification Framework


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Connector Taxonomy


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Hybrid ConnectorsReal-world situations often requiresophisticated connectors

E.g. RPC with privacy and integrity

Hardto systematically compose hybrid connectorsIntegration issues

Interoperability of connectors

Mismatching assumptionsabout interaction

Cause for project failures [GAO95, GB98]


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Composing Hybrid ConnectorsFirst order Does not combine connector types e.g. object-

oriented method call

Higher order Combine dimensions from different connector

types e.g. RPC, SSL

Not all combinations of dimensions result inmeaningful, or safeconnectorsTaxonomy provides empirical rules ofcompatibility between connector dimensions


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Connector Compatibility RulesCautions (?) Certain combination of dimensions required to be

used in conjunction are unsafe

Requires (=) Dimensions required to be used in conjunction, no

unsafe combinations

Restricts (:) Dimensions may be combined, some combinations

are unsafe

Prohibits (7) Dimensions cannot be combined


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Linkage

Parameters

Entrypoint

Invocation

Synchronicity

Cardinality

Accessibility

Cardinality

Delivery

Priority

Synchronicity

Notification

Causality

Mode

Locality

Mode

Availability

Accessibility

Cardinality

Delivery

Format

Directionality

Cardinality

State

Granularity

Cardinality

Resolution

Faulthandling

Concurrency

Transactions

Logging

Security

Scheduling

Pooling

Invocation

Data

Presentation

Deployment

Naming

Delivery

Routing

Parameters = = : : ? =Entry point = ? ? ?

Invocation ? = ? ? =

Synchronicity = = :

Cardinality = =

Accessibility = = : =

Cardinality : = = :

Delivery = : :

Priority : = :

Synchronicity : ? = = :

Notification : : : = = = = : 7 ? ? =

Causality ? =

Mode ? =

Locality ? :

Mode : : : = ? =

Availability = = ?

Accessibility : = =

Cardinality = = ?Delivery 7 = = 7

Format =

Directionality = =

Cardinality : : = ?

State = = =

Granularity = =

Cardinality =

Resolution = =

Fault handling = = = = =

Concurrency ? = ?

Transactions = = = ?

Logging = = = = = = = = = = = = ? = =

Security = = = :

Scheduling

Pooling

Invocation = 7 = = =

Data = 7 = = = =Presentation = = ? 7 = ? =

Deployment = = =

Naming = = ? = = =

Delivery = = = =

Routing =

Adaptor

Distributor

Adaptor Distributor

Arbitrator

Data access Arbitrator

Linkage

Stream

Stream

Data access

Event

Procedure

call

Event

Procedure call


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Applications/EvaluationStability of taxonomy Taxonomy applied to architecture of Linux

[MMP00]

Sparser reflexive sections reflect lack of known

incompatibilities Rich constraints indicate greater cohesion and

stability

Compatibility constraints Rule out potentially unstable connector species

Create higher-order connectors using transitive

application of constraints


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Current Status/Future WorkPublication N. R. Mehta & N. Medvidovic. Understanding

software connector compatibilities using aconnector taxonomy, SoDA 02, Bangalore, India

ACTiVE Expert knowledge capture tool for connector

compatibilities

Design guidance using compatibility matrixAlfa Composition of architectural style elements

including connectors from architectural primitives(http://sunset.usc.edu/~softarch/Alfa)

Understanding Software Connector Compatibilities

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