Class EmptyNodeSet

java.lang.Object
com.icl.saxon.expr.Expression
com.icl.saxon.expr.Value
com.icl.saxon.expr.NodeSetValue
com.icl.saxon.expr.EmptyNodeSet
public final class EmptyNodeSet extends NodeSetValue
A node-set value no nodes

  • Constructor Details

    • EmptyNodeSet

      public EmptyNodeSet()

  • Method Details

    • evaluate

      public Value evaluate(Context context)
      Evaluate the Node Set. This guarantees to return the result in sorted order.
      Overrides:
      evaluate in class NodeSetValue
      Parameters:
      context - The context for evaluation (not used)
      Returns:
      the value, unchanged

    • evaluateAsNodeSet

      public NodeSetValue evaluateAsNodeSet(Context context)
      Evaluate an expression as a NodeSet.
      Overrides:
      evaluateAsNodeSet in class NodeSetValue
      Parameters:
      context - The context in which the expression is to be evaluated
      Returns:
      the value of the expression, evaluated in the current context

    • setSorted

      public void setSorted(boolean isSorted)
      Set a flag to indicate whether the nodes are sorted. Used when the creator of the node-set knows that they are already in document order.
      Specified by:
      setSorted in class NodeSetValue
      Parameters:
      isSorted - true if the caller wishes to assert that the nodes are in document order and do not need to be further sorted

    • isSorted

      public boolean isSorted()
      Test whether the value is known to be sorted
      Specified by:
      isSorted in class NodeSetValue
      Returns:
      true if the value is known to be sorted in document order, false if it is not known whether it is sorted.

    • isContextDocumentNodeSet

      public boolean isContextDocumentNodeSet()
      Determine, in the case of an expression whose data type is Value.NODESET, whether all the nodes in the node-set are guaranteed to come from the same document as the context node. Used for optimization.
      Overrides:
      isContextDocumentNodeSet in class Expression

    • asString

      public String asString()
      Convert to string value
      Specified by:
      asString in class NodeSetValue
      Returns:
      an empty string

    • asBoolean

      public boolean asBoolean()
      Evaluate as a boolean.
      Specified by:
      asBoolean in class NodeSetValue
      Returns:
      false

    • getCount

      public int getCount()
      Count the nodes in the node-set.
      Specified by:
      getCount in class NodeSetValue
      Returns:
      zero

    • sort

      public NodeSetValue sort()
      Sort the nodes into document order. This does nothing if the nodes are already known to be sorted; to force a sort, call setSorted(false)
      Specified by:
      sort in class NodeSetValue
      Returns:
      the same NodeSetValue, after sorting. (Historic)

    • getFirst

      public NodeInfo getFirst()
      Get the first node in the nodeset (in document order)
      Specified by:
      getFirst in class NodeSetValue
      Returns:
      null

    • equals

      public boolean equals(Value other)
      Test whether this nodeset "equals" another Value
      Overrides:
      equals in class NodeSetValue
      Returns:
      a boolean giving the value of the expression, evaluated in the current context

    • notEquals

      public boolean notEquals(Value other)
      Test whether this nodeset "not-equals" another Value
      Overrides:
      notEquals in class NodeSetValue
      Returns:
      a boolean giving the value of the expression, evaluated in the current context

    • enumerate

      public NodeEnumeration enumerate()
      Return an enumeration of this nodeset value.
      Specified by:
      enumerate in class NodeSetValue