Classification of the Palladio Component Model (PCM)

The following listing helps to classify the Palladio Component Model (PCM) which is underlying the Palladio approach. In case you are preparing a taxonomy or try to identify whether specific features are supported by the PCM, this page assists your work.

  • Supported quality dimensions
    • Performance
    • Reliability
    • Costs
    • Maintainability
  • Meta-Meta-Model: UML2 and ECORE representation are available
  • Meta-Model: Own meta-model (i.e. no UML profile); the meta-modell posseses execution semantics; OCL constraints ensure model integrity
  • Meta-Model implementation: Eclipse EMF and Java
  • Interface model: Corba IDL-like
  • Supported compositions
    • Vertical: Composition by component assembly
    • Horizontal: Composition by component allocation
    • Hierarchical / nesting: Component encapsulation by composite components, subsystems, and systems
  • Component modelling
    • Three different component types (Provided Component Type, Complete Component Type, Implementation Component Type)
    • Two different component realisations (Composite Components, Basic Components)
    • Multiple type and instance levels (assembly, allocation, usage)
  • Model partitioning
    • Component repository: Definition of components and interfaces
    • System: Definition of component assembly
    • Execution environment: Definiton of hardware nodes and network
    • Component Allocation: Definition of how component are deployed on hardware nodes
  • Supported developer roles (can interact independently)
    • Component developer
    • Software architect
    • Component deployer
    • QoS analyst
  • Behaviour Model (describes single provided services of a component)
    • Internal and external actions
    • Sequences
    • Alternatives (probabilistic + guard conditions)
    • Loops (probabilistic + guard conditions)
    • Concurrency support: Fork / join / barrier
    • Semaphores
  • Interaction
    • Request / reponse (call / return, synchronous)
    • Event-based communication (asynchronous)
  • Parameterised component dimensions (i.e. dimension can vary for a readily defined component type)
    • deployment / allocation
    • usage
    • assembly
    • implementation
  • Stochastic Expression language for expressing parameterised control and data flow
    • Constants
    • Distributions
    • Mathematic calculations
    • Conditions
    • Equality and inequality checks
  • Supported states
    • Request-based (for each invocation of a provided service of a component)
      • Behaviour model state (which behaviour steps is currently executed)
      • Parameter values and paramter propagation per service request
      • Local variables
    • Allocation-based (component configuration parameters per component instance)
    • During analysis: Contention effects / blocking
    • Further state is automatically derived from allocation, assembly, and usage of components (e.g. how a component is allocated)
    • Interface protocols (mandatory orders for calling component services of an interface): Supported but not implemented

Classification of the Palladio Component Model Analyses Approaches

  • Analysis output
    • Performance: General distribution functions
    • Reliability: Mean value
    • Costs: Sum of component costs (e.g. development costs, procurement costs or total cost of ownership) and hardware costs (e.g. procurement costs, operating costs or total cost of ownership)
    • Maintainability: Expected maintainability costs

Special Features

  • The PCM accounts for the performance impact of exchangeable middlewares, e.g. application servers ("performance completion")
  • Derivation of service level agreements (SLA) from analysis results

Extended Support

  • Java stub generation from the PCM model
  • EJB stub generation from the PCM model
  • Performance prototype generation (puts load on real hardware as specified in the model)

Please note: The classification of the Palladio Component Model given in Crnković, I.; Sentilles, S.; Vulgarakis, A.; Chaudron, M. R V, "A Classification Framework for Software Component Models," Software Engineering, IEEE Transactions on , vol.37, no.5, pp.593-615, Sept.-Oct. 2011, doi: 10.1109/TSE.2010.83 is partially wrong. Please refer to the above classification.