Package net.sf.saxon.om

Class NamePool

  • public final class NamePool
extends java.lang.Object
    A NamePool holds a collection of expanded names, each containing a namespace URI, and a local name.

    Each expanded name is allocated a unique 20-bit fingerprint. The fingerprint enables the URI and the local name to be determined. Some subsystems (notably the Tinytree) use the top 10 bits to represent the prefix, but the NamePool is no longer concerned with managing prefixes, and prefixes do not have global codes.

    The NamePool has been redesigned in Saxon 9.7 to make use of two Java ConcurrentHashMaps, one from QNames to integers, one from integers to QNames. This gives better scaleability in terms of multithreaded concurrency and in terms of the capacity of the NamePool and retention of performance as the size of the vocabulary increases.

    Fingerprints in the range 0 to 1023 are reserved for system use, and are allocated as constants mainly to names in the XSLT and XML Schema namespaces: constants representing these names are found in StandardNames.

    The fingerprint -1 is reserved to mean "not known" or inapplicable.

    Modified in 9.4 to remove namespace codes.

    Modified in 9.7 to remove URI codes.

    Modified in 9.8 to remove namecodes and all handling of prefixes.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  NamePool.NamePoolLimitException
      Unchecked Exception raised when some limit in the design of the name pool is exceeded

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static int FP_MASK
      FP_MASK is a mask used to obtain a fingerprint from a nameCode.
      static int USER_DEFINED_MASK  

    • Constructor Summary

      Constructors 
      Constructor Description
      NamePool()
      Create a NamePool

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int allocateClarkName​(java.lang.String expandedName)
      Allocate a fingerprint given a Clark Name
      int allocateFingerprint​(java.lang.String uri, java.lang.String local)
      Allocate a fingerprint from the pool, or a new Name if there is not a matching one there
      java.lang.String getClarkName​(int nameCode)
      Get the Clark form of a name, given its name code or fingerprint
      java.lang.String getDisplayName​(int nameCode)
      Get the display form of a name (the QName), given its name code or fingerprint
      java.lang.String getEQName​(int nameCode)
      Get the EQName form of a name, given its name code or fingerprint
      int getFingerprint​(java.lang.String uri, java.lang.String localName)
      Get a fingerprint for the name with a given uri and local name.
      java.lang.String getLocalName​(int nameCode)
      Get the local part of a name, given its name code or fingerprint
      StructuredQName getStructuredQName​(int fingerprint)
      Get a QName for a given fingerprint.
      StructuredQName getUnprefixedQName​(int nameCode)
      Get a QName for a given namecode.
      java.lang.String getURI​(int nameCode)
      Get the namespace-URI of a name, given its name code or fingerprint
      static boolean isPrefixed​(int nameCode)
      Determine whether a given namecode has a non-empty prefix (and therefore, in the case of attributes, whether the name is in a non-null namespace
      void suggestPrefix​(java.lang.String prefix, java.lang.String uri)
      Suggest a preferred prefix to be used with a given URI
      java.lang.String suggestPrefixForURI​(java.lang.String uri)
      Suggest a prefix for a given URI.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • FP_MASK

        public static final int FP_MASK
        FP_MASK is a mask used to obtain a fingerprint from a nameCode. Given a nameCode nc, the fingerprint is nc & NamePool.FP_MASK. (In practice, Saxon code often uses the literal constant 0xfffff, to extract the bottom 20 bits).

        The difference between a fingerprint and a nameCode is that a nameCode contains information about the prefix of a name, the fingerprint depends only on the namespace URI and local name. Note that the "null" nameCode (-1) does not produce the "null" fingerprint (also -1) when this mask is applied.

        See Also:
        Constant Field Values

    • Constructor Detail

      • NamePool

        public NamePool()
        Create a NamePool

    • Method Detail

      • suggestPrefix

        public void suggestPrefix​(java.lang.String prefix,
                          java.lang.String uri)
        Suggest a preferred prefix to be used with a given URI
        Parameters:
        uri - the URI
        prefix - the suggested prefix

      • getUnprefixedQName

        public StructuredQName getUnprefixedQName​(int nameCode)
        Get a QName for a given namecode.
        Parameters:
        nameCode - a code identifying an expanded QName, e.g. of an element or attribute
        Returns:
        a qName containing the URI and local name corresponding to the supplied name code. The prefix will be set to an empty string.

      • getStructuredQName

        public StructuredQName getStructuredQName​(int fingerprint)
        Get a QName for a given fingerprint.
        Parameters:
        fingerprint - a code identifying an expanded QName, e.g. of an element or attribute
        Returns:
        a qName containing the URI and local name corresponding to the supplied fingerprint. There will be no prefix

      • isPrefixed

        public static boolean isPrefixed​(int nameCode)
        Determine whether a given namecode has a non-empty prefix (and therefore, in the case of attributes, whether the name is in a non-null namespace
        Parameters:
        nameCode - the name code to be tested
        Returns:
        true if the name has a non-empty prefix

      • suggestPrefixForURI

        public java.lang.String suggestPrefixForURI​(java.lang.String uri)
        Suggest a prefix for a given URI. If there are several, it's undefined which one is returned. If there are no prefixes registered for this URI, return null.
        Parameters:
        uri - the namespace URI
        Returns:
        a prefix that has previously been associated with this URI, if available; otherwise null

      • allocateFingerprint

        public int allocateFingerprint​(java.lang.String uri,
                               java.lang.String local)
        Allocate a fingerprint from the pool, or a new Name if there is not a matching one there
        Parameters:
        uri - the namespace URI. Use "" or null for the non-namespace.
        local - the local part of the name
        Returns:
        an integer (the "fingerprint") identifying the name within the namepool. The fingerprint omits information about the prefix, and is the same as the nameCode for the same name with a prefix equal to "".

      • getURI

        public java.lang.String getURI​(int nameCode)
        Get the namespace-URI of a name, given its name code or fingerprint
        Parameters:
        nameCode - the name code or fingerprint of a name
        Returns:
        the namespace URI corresponding to this name code. Returns "" for the no-namespace.
        Throws:
        java.lang.IllegalArgumentException - if the nameCode is not known to the NamePool.

      • getLocalName

        public java.lang.String getLocalName​(int nameCode)
        Get the local part of a name, given its name code or fingerprint
        Parameters:
        nameCode - the integer name code or fingerprint of the name
        Returns:
        the local part of the name represented by this name code or fingerprint

      • getDisplayName

        public java.lang.String getDisplayName​(int nameCode)
        Get the display form of a name (the QName), given its name code or fingerprint
        Parameters:
        nameCode - the integer name code or fingerprint of a name in the name pool
        Returns:
        the corresponding lexical QName (if a fingerprint was supplied, this will simply be the local name)

      • getClarkName

        public java.lang.String getClarkName​(int nameCode)
        Get the Clark form of a name, given its name code or fingerprint
        Parameters:
        nameCode - the integer name code or fingerprint of a name in the name pool
        Returns:
        the local name if the name is in the null namespace, or "{uri}local" otherwise. The name is always interned.

      • getEQName

        public java.lang.String getEQName​(int nameCode)
        Get the EQName form of a name, given its name code or fingerprint
        Parameters:
        nameCode - the integer name code or fingerprint of a name in the name pool
        Returns:
        the name in the form Q{}local for a name in no namespace, or Q{uri}local for a name in a namespace

      • allocateClarkName

        public int allocateClarkName​(java.lang.String expandedName)
        Allocate a fingerprint given a Clark Name
        Parameters:
        expandedName - the name in Clark notation, that is "localname" or "{uri}localName"
        Returns:
        the fingerprint of the name, which need not previously exist in the name pool

      • getFingerprint

        public int getFingerprint​(java.lang.String uri,
                          java.lang.String localName)
        Get a fingerprint for the name with a given uri and local name. These must be present in the NamePool. The fingerprint has the property that if two fingerprint are the same, the names are the same (ie. same local name and same URI).
        Parameters:
        uri - the namespace URI of the required QName
        localName - the local part of the required QName
        Returns:
        the integer fingerprint, or -1 if this is not found in the name pool