Module org.apache.jena.arq
Package org.apache.jena.riot.lang

Class LabelToNode

java.lang.Object
org.apache.jena.riot.system.MapWithScope<String,org.apache.jena.graph.Node,org.apache.jena.graph.Node>
org.apache.jena.riot.lang.LabelToNode
public class LabelToNode extends MapWithScope<String,org.apache.jena.graph.Node,org.apache.jena.graph.Node>
Allocation of Nodes (blank nodes usually) based on the graph and scope. There are various different policies. See SyntaxLabels.createLabelToNode() for getting a default setup; some of the others are for testing and debugging and may not generate legal RDF overall (e.g. reparsing the same file gets the same bNodes)

  • Constructor Details

  • Method Details

    • createScopeByDocumentHash

      public static LabelToNode createScopeByDocumentHash()
      Allocation from a single scope; just the label matters. This is the RDF syntax correct policy. See createScopeGlobal() for some history.

    • createScopeByDocumentHash

      public static LabelToNode createScopeByDocumentHash(UUID seed)
      Allocation from a single scope; just the label matters. Use this policy if repeated runs must give identical allocations
      Parameters:
      seed - Seed

    • createScopeGlobal

      public static LabelToNode createScopeGlobal()
      Allocation, with a map from seen label to node. It uses the jena-core blank node allocator and a map from label to blank node. This style works for any blank node allocation style but the map can grow to arbitrary size.

      This was the policy up to Jena 2.10.0 but it occasionally ran into problems at very large scale because it generates and remembers a new UUIDs for new each blank node. The policy changed to createScopeByDocumentHash() which calculates the blank node label needed without needing to retain previous allocations.

    • createScopeByGraph

      public static LabelToNode createScopeByGraph()
      Allocation scoped by graph and label.

    • createUseLabelAsGiven

      public static LabelToNode createUseLabelAsGiven()
      Allocation using syntax label; output is unsafe for reading (use createUseLabelEncoded() for output-input). The reverse operation is provided by NodeToLabel.createBNodeByLabelAsGiven() but the pair is unsafe for output-input. Use encoded labels for that. The main purpose of this LabelToNode is to preserve the used label for debugging.

    • createUseLabelEncoded

      public static LabelToNode createUseLabelEncoded()
      Allocation using an encoded syntax label (i.e. _:B<encoded> format from NodeFmtLib.encodeBNodeLabel(java.lang.String)). The reverse operation is provided by NodeToLabel.createBNodeByLabelEncoded(). This pair should be used to write out and recover blank node by internal id.

    • createIncremental

      public static LabelToNode createIncremental()
      Allocation, globally scoped, that uses a incrementing field to create new nodes