Package net.sf.saxon.trans

Class KeyIndex

java.lang.Object
net.sf.saxon.trans.KeyIndex
public class KeyIndex extends Object
A key index is an index maintained to support xsl:key key definitions, including both user-defined keys and keys added by the optimizer. Each key index supports one key definition (a set of xsl:key declarations with the same name) applied to one document tree.

The index can support a mixture of atomic keys of different types; there is no error caused by comparing values of different types. This relies on the fact that XPathComparable values are identical for comparable values (e.g. integers and doubles), and distinct otherwise.

With the XSLT xsl:key construct, untypedAtomic values are treated as strings. However, this structure is also used to support internally-generated keys with general comparison semantics, where untyped values are converted to the type of the other operand. To enable this to work, we maintain a list of all untypedAtomic keys present in the index; and if a search is made for some type like xs:date, we then go through this list converting each untypedAtomic value to a date and indexing it as such. In principle this can happen for an arbitrary number of data types, though it is unlikely in practice because not many types have overlapping lexical spaces.

  • Constructor Details

    • KeyIndex

      public KeyIndex(boolean isRangeKey)

  • Method Details

    • getUnderlyingMap

      public Map<AtomicMatchKey,Object> getUnderlyingMap()
      Get the underlying map
      Returns:
      the underlying map. The "Object" in the map entry is either a NodeInfo or a List<NodeInfo>

    • isCreatedInThisThread

      public boolean isCreatedInThisThread()
      Ask if the index was created in the current thread
      Returns:
      true if this index was created in this thread

    • getStatus

      public KeyIndex.Status getStatus()
      Ask if the index is under construction
      Returns:
      true if the index is still under construction

    • setStatus

      public void setStatus(KeyIndex.Status status)
      Say whether the index is under construction
      Parameters:
      status - the status of the index, for example KeyIndex.Status.UNDER_CONSTRUCTION

    • buildIndex

      public void buildIndex(KeyDefinitionSet keySet, TreeInfo doc, XPathContext context) throws XPathException
      Build the index for a particular document for a named key
      Parameters:
      keySet - The set of key definitions with this name
      doc - The source document in question
      context - The dynamic context
      Throws:
      XPathException - if a dynamic error is encountered

    • reindexUntypedValues

      public void reindexUntypedValues(BuiltInAtomicType type) throws XPathException
      Re-index untyped atomic values after conversion to a specific type. This happens when the "convertUntypedToOther" option is set (typically because this index is used to support a general comparison), and the sought value is of a type other that string or untyped atomic. We go through the index finding all untyped atomic values, converting each one to the sought type, and adding it to the index under this type.
      Parameters:
      type - the type to which untyped atomic values should be converted
      Throws:
      XPathException - if conversion of any untyped atomic value to the requested key type fails

    • isEmpty

      public boolean isEmpty()
      Ask whether the index is empty
      Returns:
      true if the index is empty

    • getNodes

      public SequenceIterator getNodes(AtomicValue soughtValue) throws XPathException
      Get the nodes with a given key value
      Parameters:
      soughtValue - The required key value
      Returns:
      an iterator over the selected nodes, always in document order with no duplicates
      Throws:
      XPathException - if a dynamic error is encountered

    • getComposite

      public SequenceIterator getComposite(SequenceIterator soughtValue) throws XPathException
      Get the nodes with a given composite key value
      Parameters:
      soughtValue - The required composite key value
      Returns:
      a list of the selected nodes, always in document order with no duplicates, or null to represent an empty list
      Throws:
      XPathException - if a dynamic error is encountered