Package net.sf.saxon.expr.elab

Class ItemElaborator

java.lang.Object
net.sf.saxon.expr.elab.Elaborator
net.sf.saxon.expr.elab.ItemElaborator
Direct Known Subclasses:
Abs.AbsElaborator, AccessorFn.AccessorFnElaborator, ArithmeticExpression.ArithmeticElaborator, AttributeGetter.AttributeGetterElaborator, BaseUri_1.BaseUriFnElaborator, CastExpression.CastExprElaborator, Ceiling.CeilingElaborator, ContextItemExpression.ContextItemElaborator, Count.CountFnElaborator, DateTimeConstructor.DateTimeFnElaborator, FirstItemExpression.FirstItemExprElaborator, Floor.FloorElaborator, IdentityComparison.IdentityComparisonElaborator, LastItemExpression.LastItemExprElaborator, NamespaceUriFn_1.NamespaceUriFnElaborator, NegateExpression.NegateElaborator, NodeName_1.NodeNameFnElaborator, Number_1.NumberFnElaborator, ParseQNameFn.QNameFnElaborator, PositionAndLast.Last.LastFnElaborator, PositionAndLast.Position.PositionFnElaborator, QNameFn.QNameFnElaborator, Root_1.RootFnElaborator, RootExpression.RootExprElaborator, Round.RoundElaborator, RoundHalfToEven.RoundHalfToEvenElaborator, SingletonIntersectExpression.SingletonIntersectElaborator, StringLength_1.StringLengthFnElaborator, SubscriptExpression.SubscriptExprElaborator, Substring.SubstringFnElaborator, Sum.SumFnElaborator, Translate.TranslateFnElaborator, ValueComparison.ValueComparisonElaborator
public abstract class ItemElaborator extends Elaborator
An ItemElaborator is an abstract superclass for use by expressions that deliver zero or one items as their result. A concrete subclass must implement the elaborateForItem() method; other evaluation methods are implemented (by default) by calling elaborateForItem().

  • Constructor Details

    • ItemElaborator

      public ItemElaborator()

  • Method Details

    • eagerly

      public SequenceEvaluator eagerly()
      Description copied from class: Elaborator
      Get a function that evaluates the underlying expression eagerly
      Overrides:
      eagerly in class Elaborator
      Returns:
      an evaluator for the expression that returns a GroundedValue. The class SequenceEvaluator is declared to return a Sequence not a GroundedValue; we can't specialize it because it's a limitation of C# delegates, but the result can safely be cast to GroundedValue.

    • elaborateForPull

      public PullEvaluator elaborateForPull()
      Description copied from class: Elaborator
      Get a function that evaluates the underlying expression in the form of a SequenceIterator
      Specified by:
      elaborateForPull in class Elaborator
      Returns:
      an evaluator for the expression that returns a SequenceIterator

    • elaborateForPush

      public PushEvaluator elaborateForPush()
      Description copied from class: Elaborator
      Get a function that evaluates the underlying expression in push mode, by writing events to an Outputter
      Specified by:
      elaborateForPush in class Elaborator
      Returns:
      an evaluator for the expression in push mode

    • elaborateForItem

      public abstract ItemEvaluator elaborateForItem()
      Description copied from class: Elaborator
      Get a function that evaluates the underlying expression in the form of a Item. This must only be called for expressions whose result has cardinality zero or one.
      Specified by:
      elaborateForItem in class Elaborator
      Returns:
      an evaluator for the expression that returns an Item, or null to represent an empty sequence.

    • elaborateForBoolean

      public BooleanEvaluator elaborateForBoolean()
      Description copied from class: Elaborator
      Get a function that evaluates the underlying expression in the form of a boolean, this being the effective boolean value of the expression.
      Specified by:
      elaborateForBoolean in class Elaborator
      Returns:
      an evaluator for the expression that returns a boolean.

    • elaborateForUnicodeString

      public UnicodeStringEvaluator elaborateForUnicodeString(boolean zeroLengthWhenAbsent)
      Description copied from class: Elaborator
      Get a function that evaluates the underlying expression in the form of a unicode string, this being the result of applying fn:string() to the result of the expression.
      Specified by:
      elaborateForUnicodeString in class Elaborator
      Parameters:
      zeroLengthWhenAbsent - if true, then when the result of the expression is an empty sequence, the result of the StringEvaluator should be a zero-length string. If false, the return value should be null. For an expression or function that never returns an empty sequence (for example, a call on string() or normalize-space()), the argument has no effect.
      Returns:
      an evaluator for the expression that returns a string.