Module org.apache.jena.arq
Package org.apache.jena.system

Class GList

java.lang.Object
org.apache.jena.system.GList
public class GList extends Object
Operations on RDF Collections (RDF Lists).

Operations may throw RDFDataException if the list is not well-formed.

Operations check for exactly rdf:first, and exactly one rdf:rest, but do not check for cycles unless noted in their javadoc.

To get a list of all the items in a list, use members(org.apache.jena.graph.Graph, org.apache.jena.graph.Node) operations, which does check for cycles, or if the list is known to be well-formed, one of the elements(org.apache.jena.graph.Graph, org.apache.jena.graph.Node) operations, which do not check for cycles.

The contains(org.apache.jena.graph.Graph, org.apache.jena.graph.Node, org.apache.jena.graph.Node) operation does not check for cycles so that repeated use on a list does not perform duplicate checking work repeatedly.

If a list is potentially mal-formed by having a cycle, check first with isWellformedList(Graph, Node) or isWellformedListEx(Graph, Node).

List validation only needs to be performed once.

List arising from parsing Turtle or TriG syntax for lists will be cycle-free.

This class is not public API.

See also GraphList which uses a "findable" abstraction in combination with GNode to work on a graph or lists of triples.

  • Constructor Summary

    Constructors
    Constructor
    Description
    GList()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static boolean
    contains(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, org.apache.jena.graph.Node item)
    Return whether an item is in the list.
    static List<org.apache.jena.graph.Node>
    elements(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
    Return the elements of a well-formed RDF list.
    static void
    elements(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, Collection<org.apache.jena.graph.Node> acc)
    Accumulate the elements of a well-formed RDF list.
    static void
    forEach(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, Consumer<org.apache.jena.graph.Node> action)
    Run an action on each element of a list, in order.
    static org.apache.jena.graph.Node
    get(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, int index)
    Return the list element at an index (indexes start at 0).
    static int
    indexOf(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, org.apache.jena.graph.Node item)
    Return the first index of an occurrence of a node in a list.
    static boolean
    isListNode(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node node)
     
    static boolean
    isWellformedList(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
    Check for a valid list; return true if well-formed else return false.
    static boolean
    isWellformedList(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, boolean closedCells)
    Check for a valid list; return true if well-formed else return false.
    static void
    isWellformedListEx(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
    Check for a valid list; throw a RDFDataException if the list is bad in some way.
    static void
    isWellformedListEx(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, boolean closedCells)
    Check for a valid list; throw a RDFDataException if the list is bad in some way.
    static Iterator<org.apache.jena.graph.Node>
    iterator(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
    Return an iterator over the list.
    static long
    listLength(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
    Return the length of a well-formed list.
    static List<org.apache.jena.graph.Node>
    members(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
    Return the members of a well-formed RDF list.
    static void
    members(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, Collection<org.apache.jena.graph.Node> acc)
    Accumulate the members of a well-formed RDF list.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • GList

      public GList()

  • Method Details

    • isWellformedListEx

      public static void isWellformedListEx(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
      Check for a valid list; throw a RDFDataException if the list is bad in some way. The RDFDataException message indicates the problem with the list.
      Parameters:
      graph -
      list -

    • isWellformedListEx

      public static void isWellformedListEx(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, boolean closedCells)
      Check for a valid list; throw a RDFDataException if the list is bad in some way. The RDFDataException message indicates the problem with the list.
      Parameters:
      graph -
      list -
      closedCells - - whether to check that only rdf:first and rdf:next are used on a list cell

    • isWellformedList

      public static boolean isWellformedList(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
      Check for a valid list; return true if well-formed else return false. Use isWellformedListEx(Graph, Node) to get an except with an informational message about the problem detected.
      Parameters:
      graph -
      list -

    • isWellformedList

      public static boolean isWellformedList(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, boolean closedCells)
      Check for a valid list; return true if well-formed else return false. Use isWellformedListEx(Graph, Node, boolean) to get an except with an informational message about the problem detected.
      Parameters:
      graph -
      list -
      closedCells - - whether to check that only rdf:first and rdf:next are used on a list cell

    • members

      public static List<org.apache.jena.graph.Node> members(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
      Return the members of a well-formed RDF list.
      Throws:
      RDFDataException - if the list is not well-formed, including if it has a cycle.

    • members

      public static void members(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, Collection<org.apache.jena.graph.Node> acc)
      Accumulate the members of a well-formed RDF list.
      Throws:
      RDFDataException - if the list is not well-formed, including if it has a cycle.

    • elements

      public static List<org.apache.jena.graph.Node> elements(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
      Return the elements of a well-formed RDF list. This operation does not check for cycles. members(org.apache.jena.graph.Graph, org.apache.jena.graph.Node) is has the same result and incorporates a well-formness cycle check.

    • elements

      public static void elements(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, Collection<org.apache.jena.graph.Node> acc)
      Accumulate the elements of a well-formed RDF list. This operation does not check for cycles.

    • forEach

      public static void forEach(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, Consumer<org.apache.jena.graph.Node> action)
      Run an action on each element of a list, in order.
      See Also:

    • listLength

      public static long listLength(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
      Return the length of a well-formed list. This operations assumes the list is well-formed. See isWellformedList(Graph, Node) for check a list.

    • iterator

      public static Iterator<org.apache.jena.graph.Node> iterator(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list)
      Return an iterator over the list. The iterator does not check for well-formed lists. Ensure the list is well-formed - isWellformedListEx(Graph, Node).
      See Also:

    • indexOf

      public static int indexOf(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, org.apache.jena.graph.Node item)
      Return the first index of an occurrence of a node in a list. Return -1 for not in list. Indexes start at 0.
      Parameters:
      graph -
      list -
      item - to check

    • contains

      public static boolean contains(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, org.apache.jena.graph.Node item)
      Return whether an item is in the list. Return for not in list.
      Parameters:
      graph -
      list -
      item - to check for

    • get

      public static org.apache.jena.graph.Node get(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node list, int index)
      Return the list element at an index (indexes start at 0).

      Do not use this to iterate over a list - consider using members(org.apache.jena.graph.Graph, org.apache.jena.graph.Node) to collect the list in a single pass.

    • isListNode

      public static boolean isListNode(org.apache.jena.graph.Graph graph, org.apache.jena.graph.Node node)