concept - SOA - The four tenets -


i'm reading soa , 4 tenets thats required make soa-application. have tried different sources, explainations twisting. im searching bit less abstract. interpretation correct?

the 4 tenets is:

  1. services have explicit boundaries
  2. services autonomous
  3. services share schema , contract, not class
  4. services interoperate based on policy

my interpretation is:

  1. the methods client may use shall easy use , defined.
  2. services shall not dependent on others. change of 1 service shall not affect in way.
  3. a scheme represent data sent, contract contains defined methods service. make system loose coupled share scheme , contract instead of classes , objects.
  4. a policy use service may particular type of binding required may used. want use service, must connect type of binding.

got answer @ programmers.stackexchange.com. im reposting answer glenh7:

you're pretty close abstractions, yes.

  1. yes. encapsulated way of looking @ this.
  2. yes, but... service can rely on other services functionality, if avoids duplication of code. nuance here in definition of dependent, guess.
  3. yes. services perform contract scheme. user provides xyz data , service provide abc action per contract.
  4. i view services operating against business policy. business policy shouldn't level of specifying binding. implementing business policy point of view, can see services dependent upon other services in order fulfill contract without duplicating code. @ broader level, business policy bunch of rules. rules interoperate nicely each. human resources, business rules have nasty habit of not getting along each other well. services instantiation of business rules. lower level point of view, if caller doesn't use advertised binding(s) caller (obviously) unable utilize service. while statement correct, it's bit of tautology doesn't enhance understanding much.

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