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

Class BindingVector

java.lang.Object
org.apache.jena.reasoner.rulesys.impl.BindingVector
All Implemented Interfaces:
BindingEnvironment
public class BindingVector extends Object implements BindingEnvironment
An implementation of a binding environment that maintains a single array of bound values for the variables in a rule. Stack management is done externally. This is intended for use in the Brule system and so also supports variable-variable bindings by use of reference chains.

  • Constructor Details

    • BindingVector

      public BindingVector(int size)
      Constructor - create an empty binding environment

    • BindingVector

      public BindingVector(Node[] env)
      Constructor - create a binding environment from a vector of bindings

    • BindingVector

      public BindingVector(BindingVector clone)
      Constructor - create a binding environment which is a copy of the given environment

  • Method Details

    • getEnvironment

      public Node[] getEnvironment()
      Return the current array of bindings. Useful for fast access to several bindings, not useful for doing updates.

    • getBinding

      public Node getBinding(Node node)
      If the node is a variable then return the current binding (null if not bound) otherwise return the node itself.

    • getGroundVersion

      public Node getGroundVersion(Node node)
      Return the most ground version of the node. If the node is not a variable just return it, if it is a variable bound in this environment return the binding, if it is an unbound variable return the variable.
      Specified by:
      getGroundVersion in interface BindingEnvironment

    • bind

      public boolean bind(int i, Node value)
      Bind the ith variable in the current environment to the given value. Checks that the new binding is compatible with any current binding. Handles aliased variables.
      Returns:
      false if the binding fails

    • bind

      public boolean bind(Node var, Node value)
      Bind a variable in the current environment to the given value. Checks that the new binding is compatible with any current binding.
      Specified by:
      bind in interface BindingEnvironment
      Parameters:
      var - a Node_RuleVariable defining the variable to bind
      value - the value to bind
      Returns:
      false if the binding fails

    • partInstantiate

      public TriplePattern partInstantiate(TriplePattern goal)
      Bind the variables in a goal pattern using the binding environment, to generate a more specialized goal
      Parameters:
      goal - the TriplePattern to be instantiated
      Returns:
      a TriplePattern obtained from the goal by substituting current bindings

    • instantiate

      public Triple instantiate(TriplePattern pattern)
      Instantiate a triple pattern against the current environment. This version handles unbound variables by turning them into bNodes.
      Specified by:
      instantiate in interface BindingEnvironment
      Parameters:
      pattern - the triple pattern to match
      Returns:
      a new, instantiated triple

    • toString

      public String toString()
      Printable form
      Overrides:
      toString in class Object

    • unify

      public static BindingVector unify(TriplePattern goal, TriplePattern head, int numRuleVars)
      Unify a goal with the head of a rule. This is a poor-man's unification, we should try switching to a more conventional global-variables-with-trail implementation in the future.
      Parameters:
      goal - the goal pattern which it being matched to a rule
      head - the head pattern of the rule which is being instantiated
      numRuleVars - the length of the environment to allocate.
      Returns:
      An initialized binding environment for the rule variables or null if the unification fails. If a variable in the environment becomes aliased to another variable through the unification this is represented by having its value in the environment be the variable to which it is aliased.

    • equals

      public boolean equals(Object o)
      Equality override
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      hash function override
      Overrides:
      hashCode in class Object