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

Class PrefixMapStd

java.lang.Object
org.apache.jena.riot.system.PrefixMapBase
org.apache.jena.riot.system.PrefixMapStd
All Implemented Interfaces:
PrefixMap
public class PrefixMapStd extends PrefixMapBase
In-memory implementation of a PrefixMap.

This also provides fast URI to prefix name calculation suitable for output. For output, calculating possible prefix names from a URI happens on every URI so this operations needs to be efficient. Normally, a prefix map is "prefix to URI" and the abbreviation is a reverse lookup, which is a scan of the value of the map. This class keeps a reverse lookup map of URI to prefix which combined with a fast, approximate for determining the split point exploiting the most common use cases, provides efficient abbreviation.

Usage for abbreviation: call PrefixMapFactory.createForOutput(PrefixMap) which copies the argument prefix map into an instance of this class, setting up the reverse lookup. This copy is cheaper than repeated reverse lookups would be.

  • Constructor Details

    • PrefixMapStd

      public PrefixMapStd()
      Creates a new empty prefix mapping

    • PrefixMapStd

      public PrefixMapStd(PrefixMap prefixMap)
      Creates a new prefix mapping copied from an existing map
      Parameters:
      prefixMap - Prefix Map

  • Method Details

    • getMapping

      public Map<String,String> getMapping()
      Description copied from interface: PrefixMap
      Return the underlying mapping, this is generally unsafe to modify and implementations may opt to return an unmodifiable view of the mapping if they wish.
      Returns:
      Underlying mapping
      See Also:

    • get

      public String get(String prefix)
      Description copied from interface: PrefixMap
      Return the URI for the prefix, or null if there is no entry for this prefix.

    • add

      public void add(String prefix, String iri)
      Description copied from interface: PrefixMap
      Add a prefix, overwrites any existing association
      Parameters:
      prefix - Prefix
      iri - Namespace IRI

    • delete

      public void delete(String prefix)
      Description copied from interface: PrefixMap
      Delete a prefix
      Parameters:
      prefix - Prefix to delete

    • clear

      public void clear()
      Description copied from interface: PrefixMap
      Clear all prefixes.

    • containsPrefix

      public boolean containsPrefix(String prefix)
      Description copied from interface: PrefixMap
      Gets whether the map contains a given prefix
      Parameters:
      prefix - Prefix
      Returns:
      True if the prefix is contained in the map, false otherwise

    • abbreviate

      public String abbreviate(String uriStr)
      Description copied from interface: PrefixMap
      Abbreviate an IRI or return null
      Specified by:
      abbreviate in interface PrefixMap
      Overrides:
      abbreviate in class PrefixMapBase
      Parameters:
      uriStr - URI to abbreviate
      Returns:
      URI in prefixed name form if possible, null otherwise

    • abbrev

      public org.apache.jena.atlas.lib.Pair<String,String> abbrev(String uriStr)
      Description copied from interface: PrefixMap
      Abbreviate an IRI and return a pair of prefix and local parts, or null.
      Specified by:
      abbrev in interface PrefixMap
      Overrides:
      abbrev in class PrefixMapBase
      Parameters:
      uriStr - URI string to abbreviate
      Returns:
      Pair of prefix and local name
      See Also:

    • isEmpty

      public boolean isEmpty()
      Description copied from interface: PrefixMap
      Return whether the prefix map is empty or not.

    • size

      public int size()
      Description copied from interface: PrefixMap
      Return the number of entries in the prefix map.