Module org.apache.jena.core
Package org.apache.jena.reasoner.rulesys.impl

Class RETEEngine

java.lang.Object
org.apache.jena.reasoner.rulesys.impl.RETEEngine
All Implemented Interfaces:
FRuleEngineI
public class RETEEngine extends Object implements FRuleEngineI
A RETE version of the forward rule system engine. It needs to reference an enclosing ForwardInfGraphI which holds the raw data and deductions.

  • Constructor Details

    • RETEEngine

      public RETEEngine(ForwardRuleInfGraphI parent, List<Rule> rules)
      Constructor.
      Parameters:
      parent - the F or FB infGraph that it using this engine, the parent graph holds the deductions graph and source data.
      rules - the rule set to be processed

    • RETEEngine

      public RETEEngine(ForwardRuleInfGraphI parent)
      Constructor. Build an empty engine to which rules must be added using setRuleStore().
      Parameters:
      parent - the F or FB infGraph that it using this engine, the parent graph holds the deductions graph and source data.

  • Method Details

    • init

      public void init(boolean ignoreBrules, Finder inserts)
      Process all available data. This should be called once a deductions graph has be prepared and loaded with any precomputed deductions. It will process the rule axioms and all relevant existing exiting data entries.
      Specified by:
      init in interface FRuleEngineI
      Parameters:
      ignoreBrules - set to true if rules written in backward notation should be ignored
      inserts - the set of triples to be processed, normally this is the raw data graph but may include additional deductions made by preprocessing hooks

    • fastInit

      public void fastInit(Finder inserts)
      Process all available data. This version expects that all the axioms have already be preprocessed and the clause index already exists.
      Specified by:
      fastInit in interface FRuleEngineI
      Parameters:
      inserts - the set of triples to be processed, normally this is the raw data graph but may include additional deductions made by preprocessing hooks

    • add

      public void add(Triple t)
      Add one triple to the data graph, run any rules triggered by the new data item, recursively adding any generated triples.
      Specified by:
      add in interface FRuleEngineI

    • delete

      public boolean delete(Triple t)
      Remove one triple to the data graph.
      Specified by:
      delete in interface FRuleEngineI
      Returns:
      true if the effects could be correctly propagated or false if not (in which case the entire engine should be restarted).

    • getNRulesFired

      public long getNRulesFired()
      Return the number of rules fired since this rule engine instance was created and initialized
      Specified by:
      getNRulesFired in interface FRuleEngineI

    • shouldTrace

      public boolean shouldTrace()
      Return true if the internal engine state means that tracing is worthwhile. It will return false during the axiom bootstrap phase.
      Specified by:
      shouldTrace in interface FRuleEngineI

    • setDerivationLogging

      public void setDerivationLogging(boolean recordDerivations)
      Set to true to enable derivation caching
      Specified by:
      setDerivationLogging in interface FRuleEngineI

    • getRuleStore

      public Object getRuleStore()
      Access the precomputed internal rule form. Used when precomputing the internal axiom closures.
      Specified by:
      getRuleStore in interface FRuleEngineI

    • setRuleStore

      public void setRuleStore(Object ruleStore)
      Set the internal rule from a precomputed state.
      Specified by:
      setRuleStore in interface FRuleEngineI

    • requestRuleFiring

      public void requestRuleFiring(Rule rule, BindingEnvironment env, boolean isAdd)
      Add a rule firing request to the conflict set.

    • compile

      public void compile(List<Rule> rules, boolean ignoreBrules)
      Compile a list of rules into the internal rule store representation.
      Parameters:
      rules - the list of Rule objects
      ignoreBrules - set to true if rules written in backward notation should be ignored

    • addTriple

      public void addTriple(Triple triple, boolean deduction)
      Add a new triple to the network.
      Parameters:
      triple - the new triple
      deduction - true if the triple has been generated by the rules and so should be added to the deductions graph.

    • deleteTriple

      public void deleteTriple(Triple triple, boolean deduction)
      Remove a new triple from the network.
      Parameters:
      triple - the new triple
      deduction - true if the remove has been generated by the rules

    • runAll

      public void runAll()
      Process the queue of pending insert/deletes until the queues are empty. Public to simplify unit tests - not normally called directly.

    • testTripleInsert

      public void testTripleInsert(Triple t)
      This fires a triple into the current RETE network. This format of call is used in the unit testing but needs to be public because the tester is in another package.