Package org.apache.jena.reasoner.rulesys

Class Util

  • public class Util
extends java.lang.Object
    A small random collection of utility functions used by the rule systems.

    • Constructor Summary

      Constructors 
      Constructor Description
      Util()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static java.lang.Boolean checkBinaryPredicate​(Property predicate, Resource configuration)
      Helper method - extracts the truth of a boolean configuration predicate.
      static boolean comparable​(Node n1, Node n2)
      Test if two literals are comparable by an order operator (both numbers or both times)
      static int compareInstants​(Node n1, Node n2)
      Compare two time Instant nodes.
      static int compareNumbers​(Node n1, Node n2)
      Compare two numeric nodes.
      static int compareTypedLiterals​(Node n1, Node n2)
      General order comparator for typed literal nodes, works for all numbers and for date times.
      static boolean convertBooleanPredicateArg​(Property parameter, java.lang.Object value)
      Convert the value of a boolean configuration parameter to a boolean value.
      static int convertIntegerPredicateArg​(Property parameter, java.lang.Object value)
      Convert the value of an integer configuration parameter to an int value.
      static java.util.List<Node> convertList​(Node root, RuleContext context)
      Convert an (assumed well formed) RDF list to a java list of Nodes
      static java.lang.Integer getIntegerPredicate​(Property predicate, Resource configuration)
      Helper method - extracts the value of an integer configuration predicate.
      static int getIntValue​(Node n)
      Return the integer value of a literal node
      static Node getPropValue​(Node root, Node prop, Graph context)
      Helper - returns the (singleton) value for the given property on the given root node in the data graph.
      static Node getPropValue​(Node root, Node prop, Finder context)
      Helper - returns the (singleton) value for the given property on the given root node in the data graph.
      static Node getPropValue​(Node root, Node prop, RuleContext context)
      Helper - returns the (singleton) value for the given property on the given root node in the data graph.
      static boolean isInstant​(Node n)
      Check whether a Node is an Instant (DateTime) value
      static boolean isNumeric​(Node n)
      Check whether a Node is a numeric (integer) value
      static Rule.Parser loadRuleParserFromResourceFile​(java.lang.String filename)
      Open a resource file and read it all into a single string.
      static java.lang.String loadURLFile​(java.lang.String urlStr)
      Open a file defined by a URL and read all of it into a single string.
      static Node makeDoubleNode​(double value)
      Construct a new double valued node
      static Node makeIntNode​(int value)
      Construct a new integer valued node
      static Node makeList​(Node[] nodes, Graph graph)
      Construct an RDF list from the given array of nodes and assert it in the graph returning the head of the list.
      static Node makeLongNode​(long value)
      Construct a new long valued node
      static void updateParameter​(Resource config, Property parameter, java.lang.Object value)
      Replace the value for a given parameter on the resource by a new value.

      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • Util

        public Util()

    • Method Detail

      • isNumeric

        public static boolean isNumeric​(Node n)
        Check whether a Node is a numeric (integer) value

      • getIntValue

        public static int getIntValue​(Node n)
        Return the integer value of a literal node

      • isInstant

        public static boolean isInstant​(Node n)
        Check whether a Node is an Instant (DateTime) value

      • comparable

        public static boolean comparable​(Node n1,
                                 Node n2)
        Test if two literals are comparable by an order operator (both numbers or both times)

      • compareNumbers

        public static int compareNumbers​(Node n1,
                                 Node n2)
        Compare two numeric nodes.
        Parameters:
        n1 - the first numeric valued literal node
        n2 - the second numeric valued literal node
        Returns:
        -1 if n1 is less than n2, 0 if n1 equals n2 and +1 if n1 greater than n2
        Throws:
        java.lang.ClassCastException - if either node is not numeric

      • compareInstants

        public static int compareInstants​(Node n1,
                                  Node n2)
        Compare two time Instant nodes.
        Parameters:
        n1 - the first time instant (XSDDateTime) valued literal node
        n2 - the second time instant (XSDDateTime) valued literal node
        Returns:
        -1 if n1 is less than n2, 0 if n1 equals n2 and +1 if n1 greater than n2
        Throws:
        java.lang.ClassCastException - if either not is not numeric

      • compareTypedLiterals

        public static int compareTypedLiterals​(Node n1,
                                       Node n2)
        General order comparator for typed literal nodes, works for all numbers and for date times.

      • getPropValue

        public static Node getPropValue​(Node root,
                                Node prop,
                                Finder context)
        Helper - returns the (singleton) value for the given property on the given root node in the data graph.

      • getPropValue

        public static Node getPropValue​(Node root,
                                Node prop,
                                Graph context)
        Helper - returns the (singleton) value for the given property on the given root node in the data graph.

      • getPropValue

        public static Node getPropValue​(Node root,
                                Node prop,
                                RuleContext context)
        Helper - returns the (singleton) value for the given property on the given root node in the data graph.

      • convertList

        public static java.util.List<Node> convertList​(Node root,
                                               RuleContext context)
        Convert an (assumed well formed) RDF list to a java list of Nodes
        Parameters:
        root - the root node of the list
        context - the graph containing the list assertions

      • makeIntNode

        public static Node makeIntNode​(int value)
        Construct a new integer valued node

      • makeLongNode

        public static Node makeLongNode​(long value)
        Construct a new long valued node

      • makeDoubleNode

        public static Node makeDoubleNode​(double value)
        Construct a new double valued node

      • makeList

        public static Node makeList​(Node[] nodes,
                            Graph graph)
        Construct an RDF list from the given array of nodes and assert it in the graph returning the head of the list.

      • loadRuleParserFromResourceFile

        public static Rule.Parser loadRuleParserFromResourceFile​(java.lang.String filename)
        Open a resource file and read it all into a single string. Treats lines starting with # as comment lines, as per stringFromReader

      • loadURLFile

        public static java.lang.String loadURLFile​(java.lang.String urlStr)
                                    throws java.io.IOException
        Open a file defined by a URL and read all of it into a single string. If the URL fails it will try a plain file name as well.
        Throws:
        java.io.IOException

      • checkBinaryPredicate

        public static java.lang.Boolean checkBinaryPredicate​(Property predicate,
                                                     Resource configuration)
        Helper method - extracts the truth of a boolean configuration predicate.
        Parameters:
        predicate - the predicate to be tested
        configuration - the configuration node
        Returns:
        null if there is no setting otherwise a Boolean giving the setting value

      • getIntegerPredicate

        public static java.lang.Integer getIntegerPredicate​(Property predicate,
                                                    Resource configuration)
        Helper method - extracts the value of an integer configuration predicate.
        Parameters:
        predicate - the predicate to be tested
        configuration - the configuration node
        Returns:
        null if there is no such configuration parameter otherwise the value as an integer

      • convertBooleanPredicateArg

        public static boolean convertBooleanPredicateArg​(Property parameter,
                                                 java.lang.Object value)
        Convert the value of a boolean configuration parameter to a boolean value. Allows the value to be specified using a String or Boolean.
        Parameters:
        parameter - the configuration property being set (to help with error messages)
        value - the parameter value
        Returns:
        the converted value
        Throws:
        IllegalParameterException - if the value can't be converted

      • convertIntegerPredicateArg

        public static int convertIntegerPredicateArg​(Property parameter,
                                             java.lang.Object value)
        Convert the value of an integer configuration parameter to an int value. Allows the value to be specified using a String or Number.
        Parameters:
        parameter - the configuration property being set (to help with error messages)
        value - the parameter value
        Returns:
        the converted value
        Throws:
        IllegalParameterException - if the value can't be converted

      • updateParameter

        public static void updateParameter​(Resource config,
                                   Property parameter,
                                   java.lang.Object value)
        Replace the value for a given parameter on the resource by a new value.
        Parameters:
        config - the resource whose values are to be updated
        parameter - a predicate defining the parameter to be set
        value - the new value