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

Class Util

java.lang.Object
org.apache.jena.reasoner.rulesys.Util
public class Util extends Object
A small random collection of utility functions used by the rule systems.

  • Constructor Details

    • Util

      public Util()

  • Method Details

    • 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:
      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:
      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 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(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 String loadURLFile(String urlStr) throws 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:
      IOException

    • checkBinaryPredicate

      public static 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 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, 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, 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, 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