Class UserFunctionCall

All Implemented Interfaces:
Serializable, SourceLocator, Container, Expression, InstructionInfoProvider

public class UserFunctionCall extends FunctionCall implements InstructionInfoProvider
This class represents a call to a function defined in the stylesheet or query. It is used for all user-defined functions in XQuery, and for a limited class of user-defined functions in XSLT: those that can be reduced to the evaluation of a single expression.
See Also:
  • Constructor Details

    • UserFunctionCall

      public UserFunctionCall()
  • Method Details

    • setStaticType

      public void setStaticType(SequenceType type)
      Set the static type
    • setFunction

      public void setFunction(UserFunction compiledFunction, StaticContext env) throws XPathException
      Create the reference to the function to be called, and validate for consistency
      Throws:
      XPathException
    • checkFunctionCall

      public void checkFunctionCall(UserFunction compiledFunction, StaticContext env) throws XPathException
      Check the function call against the declared function signature
      Throws:
      XPathException
    • getFunction

      public UserFunction getFunction()
      Get the function that is being called by this function call
    • setConfirmed

      public void setConfirmed(boolean conf)
      Set this function as confirmed (the function being called is known to exist) or not
    • isConfirmed

      public boolean isConfirmed()
      Determine whether this function call is confirmed
    • getArguments

      public Expression[] getArguments()
      Get the arguments (the expressions supplied in the function call)
      Overrides:
      getArguments in class FunctionCall
    • checkArguments

      public void checkArguments(StaticContext env) throws XPathException
      Method called during the type checking phase
      Specified by:
      checkArguments in class FunctionCall
      Throws:
      XPathException
    • preEvaluate

      public Expression preEvaluate(StaticContext env)
      Pre-evaluate a function at compile time. This version of the method suppresses early evaluation by doing nothing.
      Overrides:
      preEvaluate in class FunctionCall
    • getItemType

      public ItemType getItemType(TypeHierarchy th)
      Determine the data type of the expression, if possible
      Specified by:
      getItemType in interface Expression
      Parameters:
      th -
      Returns:
      Type.ITEM (meaning not known in advance)
    • getIntrinsicDependencies

      public int getIntrinsicDependencies()
      Description copied from class: ComputedExpression
      Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".
      Overrides:
      getIntrinsicDependencies in class ComputedExpression
      Returns:
      a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
    • computeCardinality

      public int computeCardinality()
      Determine the cardinality of the result
      Specified by:
      computeCardinality in class ComputedExpression
    • simplify

      public Expression simplify(StaticContext env) throws XPathException
      Simplify the function call
      Specified by:
      simplify in interface Expression
      Overrides:
      simplify in class FunctionCall
      Parameters:
      env - the static context
      Returns:
      the simplified expression
      Throws:
      XPathException - if an error is discovered during expression rewriting
    • typeCheck

      public Expression typeCheck(StaticContext env, ItemType contextItemType) throws XPathException
      Description copied from class: FunctionCall
      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.
      Specified by:
      typeCheck in interface Expression
      Overrides:
      typeCheck in class FunctionCall
      Parameters:
      env - the static context of the expression
      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
    • optimize

      public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException
      Description copied from class: FunctionCall
      Perform optimisation of an expression and its subexpressions.

      This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

      Specified by:
      optimize in interface Expression
      Overrides:
      optimize in class FunctionCall
      Parameters:
      opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.
      env - the static context of the expression
      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
    • computeArgumentEvaluationModes

      public void computeArgumentEvaluationModes()
    • markTailFunctionCalls

      public boolean markTailFunctionCalls(int nameCode, int arity)
      Mark tail-recursive calls on stylesheet functions. This marks the function call as tailRecursive if if is a call to the containing function, and in this case it also returns "true" to the caller to indicate that a tail call was found.
      Overrides:
      markTailFunctionCalls in class ComputedExpression
      Returns:
      true if a tail recursive call was found and if this call accounts for the whole of the value.
    • getImplementationMethod

      public int getImplementationMethod()
      Description copied from class: ComputedExpression
      An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided directly. The other methods will always be available indirectly, using an implementation that relies on one of the other methods.
      Specified by:
      getImplementationMethod in interface Expression
      Overrides:
      getImplementationMethod in class ComputedExpression
    • evaluateItem

      public Item evaluateItem(XPathContext c) throws XPathException
      Call the function, returning the value as an item. This method will be used only when the cardinality is zero or one. If the function is tail recursive, it returns an Object representing the arguments to the next (recursive) call
      Specified by:
      evaluateItem in interface Expression
      Overrides:
      evaluateItem in class ComputedExpression
      Parameters:
      c - 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
    • iterate

      public SequenceIterator iterate(XPathContext c) throws XPathException
      Call the function, returning an iterator over the results. (But if the function is tail recursive, it returns an iterator over the arguments of the recursive call)
      Specified by:
      iterate in interface Expression
      Overrides:
      iterate in class ComputedExpression
      Parameters:
      c - 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
    • process

      public void process(XPathContext context) throws XPathException
      Process the function call in push mode
      Specified by:
      process in interface Expression
      Overrides:
      process in class ComputedExpression
      Parameters:
      context -
      Throws:
      XPathException
    • dynamicCall

      public ValueRepresentation dynamicCall(ValueRepresentation[] suppliedArguments, XPathContext context) throws XPathException
      Call the function dynamically. For this to be possible, the static arguments of the function call must have been set up as SuppliedParameterReference objects. The actual arguments are placed on the callee's stack, and the type conversion takes place "in situ".
      Throws:
      XPathException
    • display

      public void display(int level, PrintStream out, Configuration config)
      Description copied from interface: Expression
      Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
      Specified by:
      display in interface Expression
      Overrides:
      display in class FunctionCall
      Parameters:
      level - indentation level for this expression
      out - Output destination
      config -
    • getInstructionInfo

      public InstructionInfo getInstructionInfo()
      Get diagnostic information about this expression
      Specified by:
      getInstructionInfo in interface InstructionInfoProvider
      Overrides:
      getInstructionInfo in class ComputedExpression