Class: ActiveRubinstein::JenaQuery

Inherits:
Base
  • Object
show all
Defined in:
lib/active_rubinstein/jena_query.rb

Overview

JenaQuery translates an ActiveRubic query to JeanLuc::Picard over the DRb via method_missing.

execute accepts these actions:

  • :instances_of :class => getInstances

  • :parents the same method is used for both instances and classes, but the actual method in Java is different :class || :subject

    is_class? => getParents
is_subject? => getInstanceClass

  • :ancestors :class => getAncestors

  • :children :class => getChildren

  • :descendants :class => getDescendants

  • :roots :ontology => getRoot

  • :classes_within :class, :radius => getClassesWithin

  • :inverse :property => getInverse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Base

#hello, #roll, set_language, #shuffle

Constructor Details

#initialize ⇒ JenaQuery

picks a JenaEndpoint from the server pool.



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# File 'lib/active_rubinstein/jena_query.rb', line 63

def initialize
  server = $serverPool[ :jena ].first
  unless server.ping
    raise ConnectionFailedError, $!.message
  else
    @@jena = server
    @@log.rubinstein "@@jena = #{server.inspect}"
  end
end

Instance Attribute Details

#language ⇒ Object

allow to set query language



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# File 'lib/active_rubinstein/jena_query.rb', line 60

def language
  @language
end

Class Method Details

.execute(query, options) ⇒ Object

analyzes the query to find the correct method to execute



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# File 'lib/active_rubinstein/jena_query.rb', line 78

def execute( query, options )
  if query.is_a? Symbol or query.is_a? RDFS::Resource
    case query
    when :instances_of
      subject = options[ :class ]
      if subject
        # 2nd parameter sets the reasoner
        self.getInstances( subject, false )
      end
    when :parents
      # the same method is used for both instances and classes,
      # but the actual method in Java is different
      subject = options[ :subject ]
      if subject.is_class? then
        self.getParents( subject )
      else
        self.getInstanceClass( subject )
      end
    when :ancestors
      subject = options[ :subject ]
      if subject.is_class? then
        self.getAncestors( subject )
      elsif subject.is_a? RDFS::Resource then
        ancestors = Array.new
        subject.parents.each do |parent|
          ancestors << parent
          ancestors << self.getAncestors( parent )
        end
        return ancestors.flatten
      end
    when :children
      subject = options[ :class ]
      if subject
        self.getChildren( subject )
      end
    when :descendants
      subject = options[ :class ]
      if subject
        self.getDescendants( subject )
      end
    when :roots
      ontology = options[ :ontology ]
      if ontology
        self.getRoot( ontology )
      end
    when :classes_within
      subject = options[ :class ]
      radius = options[ :radius ] || 0.2
      if subject
        # 2nd parameter sets the reasoner
        self.getClassesWithin( subject, radius )
      end
    when :properties then
      subject = options[ :subject ]
      if subject
        self.getProperties( subject )
      end
    when :inverse
      property = options[ :property ]
      if property
        self.getInverse( property )
      end

    else # construct common SPARQL
      sparql = ActiveRubinstein::SparqlFormulator.construct( query, options )
      return self.query( sparql, options ) if sparql
    end

  elsif query.is_a? Query then
    @@log.query query.to_sp
    return self.query( query, options )
  end
end

.server ⇒ Object

returns the server object



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# File 'lib/active_rubinstein/jena_query.rb', line 153

def server
  @@jena
end