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- Represent the widely distributed nature of a typical SOA so that SCA presents a cross enterprise description of assembled components
- Support policy matching where components require particular resources and hence particular, and separate, nodes
- HA/Load balancing/Performance scenarios where a single component appears on multiple nodes
- Load balancing/Performance scenarios where domain is spread across multiple nodes (same as 1 & 2 I believe)
- Dynamic wiring/Registry based service location, i.e. the SCA binding is called upon to automatically locate services based on registry entries.(overlaps with all of the above)
Terminology
See http://cwiki.apache.org/confluence/display/TUSCANYWIKI/Terminology
Scoping The Distribution Problem
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So the initial area of consideration is how the components of a domain are associated with runtime nodes (2).
Cardinality
In the non-distributed case a single runtime node loads all contributions and runs all components.
In the distributed case, A Domain may span many nodes.
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Scenario - Simple Distributed Components
In this basic scenario a number of composites are started across nodes from the command line and once they are all started messages are send through the application
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Th logical view of how the different parts of the solution communicate is.
Messages - the application messages that flow between configured components. Messages will flow over bindings described excplicitly in the assembly model or across the default binding used when no explicit binding is specified.
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Based on the calculator scenario we can take a general view of how the domain organizes running application
However there are a number of specific configurations to consider which affect the way that configuration and events are distributed.
Domain Driven
Node Driven
Stand Alone Node
Remote Domain Control
APIs
SCADomainFactory
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