Class NumericPromoter

All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, InstructionInfo, Locator

public final class NumericPromoter extends UnaryExpression
A NumericPromoter performs numeric promotion on each item in a supplied sequence
See Also:
  • Constructor Details

    • NumericPromoter

      public NumericPromoter(Expression sequence, BuiltInAtomicType requiredType)
      Constructor
      Parameters:
      sequence - this must be a sequence of atomic values. This is not checked; a ClassCastException will occur if the precondition is not satisfied.
      requiredType - the item type to which all items in the sequence should be converted, using the rules for "cast as".
  • Method Details

    • simplify

      public Expression simplify(ExpressionVisitor visitor) throws XPathException
      Simplify an expression
      Overrides:
      simplify in class UnaryExpression
      Parameters:
      visitor - an expression visitor
      Returns:
      the simplified expression
      Throws:
      XPathException - if an error is discovered during expression rewriting
    • typeCheck

      public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
      Type-check the expression
      Overrides:
      typeCheck in class UnaryExpression
      Parameters:
      visitor - an expression visitor
      contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
      Returns:
      the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
      Throws:
      XPathException - if an error is discovered during this phase (typically a type error)
    • optimize

      public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
      Optimize the expression
      Overrides:
      optimize in class UnaryExpression
      Parameters:
      visitor - an expression visitor
      contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
      Returns:
      the original expression, rewritten if appropriate to optimize execution
      Throws:
      XPathException - if an error is discovered during this phase (typically a type error)
    • iterate

      public SequenceIterator iterate(XPathContext context) throws XPathException
      Iterate over the sequence of values
      Specified by:
      iterate in interface SequenceIterable
      Overrides:
      iterate in class Expression
      Parameters:
      context - supplies the context for evaluation
      Returns:
      a SequenceIterator that can be used to iterate over the result of the expression
      Throws:
      XPathException - if any dynamic error occurs evaluating the expression
    • copy

      public Expression copy()
      Copy an expression. This makes a deep copy.
      Specified by:
      copy in class Expression
      Returns:
      the copy of the original expression
    • evaluateItem

      public Item evaluateItem(XPathContext context) throws XPathException
      Evaluate as an Item. This should only be called if the expression has cardinality zero-or-one
      Specified by:
      evaluateItem in interface EvaluableItem
      Overrides:
      evaluateItem in class Expression
      Parameters:
      context - The context in which the expression is to be evaluated
      Returns:
      the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
      Throws:
      XPathException - if any dynamic error occurs evaluating the expression
    • getRequiredType

      public int getRequiredType()
      Get the required type. Always StandardNames.XS_DOUBLE or StandardNames.XS_FLOAT
      Returns:
      the fingerprint of the name of the required type
    • getItemType

      public ItemType getItemType(TypeHierarchy th)
      Determine the data type of the items returned by the expression, if possible
      Overrides:
      getItemType in class UnaryExpression
      Parameters:
      th - the type hierarchy cache
      Returns:
      a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known in advance)
    • equals

      public boolean equals(Object other)
      Is this expression the same as another expression?
      Overrides:
      equals in class UnaryExpression
    • explain

      public void explain(ExpressionPresenter out)
      Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
      Overrides:
      explain in class UnaryExpression
      Parameters:
      out - the expression presenter used to display the structure