Class NumberFn

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

public class NumberFn extends SystemFunction
Implements the XPath number() function.
See Also:
  • Constructor Details

    • NumberFn

      public NumberFn()
  • Method Details

    • simplify

      public Expression simplify(ExpressionVisitor visitor) throws XPathException
      Simplify and validate. This is a pure function so it can be simplified in advance if the arguments are known
      Overrides:
      simplify in class FunctionCall
      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, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
      Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.
      Overrides:
      typeCheck in class FunctionCall
      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)
    • addDocToPathMap

      public PathMap.PathMapNodeSet addDocToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodes)
      Add a representation of a doc() call or similar function to a PathMap. This is a convenience method called by the addToPathMap() methods for doc(), document(), collection() and similar functions. These all create a new root expression in the path map.
      Overrides:
      addDocToPathMap in class SystemFunction
      Parameters:
      pathMap - the PathMap to which the expression should be added
      pathMapNodes - the node in the PathMap representing the focus at the point where this expression is called. Set to null if this expression appears at the top level.
      Returns:
      the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression
    • evaluateItem

      public Item evaluateItem(XPathContext context) throws XPathException
      Evaluate in a general context
      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
    • convert

      public static DoubleValue convert(AtomicValue value, Configuration config)
      Static method to perform the same conversion as the number() function. This is different from the convert(Type.DOUBLE) in that it produces NaN rather than an error for non-numeric operands.
      Parameters:
      value - the value to be converted
      config -
      Returns:
      the result of the conversion