Compose Runtime

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Compose Runtime

• Pascal Dürr

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Filters_at_Runtime in Compose
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MessageHandlingFacility

• Interfaces with the code
• ILICIT redirects all interesting things to the
  MHF
• Events redirected to the MHF
• Application Start
• Handle message calls
• Constructor notification
• Handle casting requests

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Application Start

• A special start application is inserted in the
  code by ILICIT
• ltapplication name"Jukebox.TheJukebox"gt
• ltnotifyStart id"application_start"/gt
• lt/applicationgt
• Location of repository.xml
• Runtime debug level
• MessageHandlingFacility is called with this info

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Runtime deserializing

• The runtime deserializes the repository xml file.
• The entire (public) repository is restored.
• Pay attention in CompileTime
• No interfaces as types
• No transient stuff
• No java 1.2 stuff
• Empty constructor

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Runtime shadows

• For each compile time entity we have a runtime
  shadow.
• This shadow is instantiate at load time
• Each runtime entity implements an interpret
  method
• Message m ? the message object
• Context c ? a context, used for dynamic info
• The RepositoryLinker links the compile time to
  the runtime.

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Code example FilterElementRuntime

• public boolean interpret(Message m, Dictionary
  context)
• if(this.conditionpart.interpret(m,context))
• boolean matches false
• for(int i0 iltthis.matchingPatterns.size()
  i)
• MatchingPatternRuntime mpr
  (MPR)this.matchingPatterns.get(i)
• matches matches mpr.interpret(m,context)
• if(this.theEnableOperatorTypeRuntime
  instanceof EnableOperatorRuntime)
• returnvalue matches
• else if(this.theEnableOperatorTypeRuntime
  instanceof DisableOperatorRuntime)
• returnvalue !matches
• return matches
• else

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Handle messages

• A message is delivered to MHF
• If an ObjectManager does not yet exists one is
  create
• All internals for the superimposed FMs are
  instantiated
• All externals are linked
• Next the ObjectManager handles the
  incomming/outgoing messages.

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• For each call the following is done
• First the message is passes through all output
  filters of the imposed filtermodules of the
  sender
• Then the message is passes through all input
  filters of the target

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• The evaluation of a filter is based on the
  interpreter pattern
• The evaluation of a filtermodule is atomic.
• The ObjectManager locks the evaluation of new
  message until the old one is done.
• So self calls cause deadlock!
• Each filter have two actions