Package net.sf.saxon.expr

Class UserFunctionCall

java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.expr.UserFunctionCall
All Implemented Interfaces:
ComponentInvocation, ContextOriginator, ExportAgent, Locatable, UserFunctionResolvable, IdentityComparable, Traceable
public class UserFunctionCall extends FunctionCall implements UserFunctionResolvable, ComponentInvocation, ContextOriginator
This class represents a call to a user-defined function in the stylesheet or query.

  • Field Details

  • Constructor Details

    • UserFunctionCall

      public UserFunctionCall()
      Create a function call to a user-written function in a query or stylesheet

    • UserFunctionCall

      public UserFunctionCall(UnboundFunctionLibrary.UnboundFunctionCallDetails details)
      Create an unbound function call (typically, a forwards reference in XQuery)

  • Method Details

    • isBeingInlined

      public boolean isBeingInlined()

    • setBeingInlined

      public void setBeingInlined(boolean beingInlined)

    • copyFrom

      public void copyFrom(UserFunctionCall ufc2)
      Copy details from another user function call

    • setFunctionName

      public final void setFunctionName(StructuredQName name)
      Set the name of the function being called
      Parameters:
      name - the name of the function

    • setStaticType

      public void setStaticType(SequenceType type)
      Set the static type
      Parameters:
      type - the static type of the result of the function call

    • setFunction

      public void setFunction(UserFunction compiledFunction)
      Create the reference to the function to be called
      Specified by:
      setFunction in interface UserFunctionResolvable
      Parameters:
      compiledFunction - the function being called

    • setBindingSlot

      public void setBindingSlot(int slot)
      Set the binding slot to be used. This is the offset within the binding vector of the containing component where the actual target template is to be found. The target function is not held directly in the UserFunctionCall expression itself because it can be overridden in a using package.
      Specified by:
      setBindingSlot in interface ComponentInvocation
      Parameters:
      slot - the offset in the binding vector of the containing package where the target template can be found.

    • getBindingSlot

      public int getBindingSlot()
      Get the binding slot to be used. This is the offset within the binding vector of the containing component where the actual target template is to be found.
      Specified by:
      getBindingSlot in interface ComponentInvocation
      Returns:
      the offset in the binding vector of the containing package where the target template can be found.

    • getFunction

      public UserFunction getFunction()
      Get the function that is being called by this function call. This is the provisional binding: the actual function might be an override of this one.
      Returns:
      the function being called

    • getFixedTarget

      public Component getFixedTarget()
      Description copied from interface: ComponentInvocation
      Get the target component if this is known in advance, that is, if the target component is private or final, or in some other cases such as xsl:original. Otherwise, return null.
      Specified by:
      getFixedTarget in interface ComponentInvocation
      Returns:
      the bound component if the binding has been fixed

    • getUnboundCallDetails

      public UnboundFunctionLibrary.UnboundFunctionCallDetails getUnboundCallDetails()

    • isTailCall

      public boolean isTailCall()
      Determine whether this is a tail call (not necessarily a recursive tail call)
      Returns:
      true if this function call is a tail call

    • isRecursiveTailCall

      public boolean isRecursiveTailCall()

    • getFunctionName

      public final StructuredQName getFunctionName()
      Get the qualified of the function being called
      Specified by:
      getFunctionName in class FunctionCall
      Returns:
      the qualified name

    • getSymbolicName

      public SymbolicName getSymbolicName()
      Description copied from interface: ComponentInvocation
      Get the symbolic name of the component that this invocation references
      Specified by:
      getSymbolicName in interface ComponentInvocation
      Returns:
      the symbolic name of the target component, or null if there is no component referenced

    • getTarget

      public Component getTarget()

    • allocateArgumentEvaluators

      public void allocateArgumentEvaluators()

    • getArgumentEvaluators

      public SequenceEvaluator[] getArgumentEvaluators()

    • preEvaluate

      public Expression preEvaluate(ExpressionVisitor visitor)
      Pre-evaluate a function at compile time. This version of the method suppresses early evaluation by doing nothing.
      Overrides:
      preEvaluate in class FunctionCall
      Parameters:
      visitor - an expression visitor
      Returns:
      the result of the early evaluation, or the original expression, or potentially a simplified expression

    • getItemType

      public ItemType getItemType()
      Determine the data type of the expression, if possible
      Specified by:
      getItemType in class Expression
      Returns:
      Type.ITEM (meaning not known in advance)

    • getStaticUType

      public UType getStaticUType(UType contextItemType)
      Get the static type of the expression as a UType, following precisely the type inference rules defined in the XSLT 3.0 specification.
      Overrides:
      getStaticUType in class Expression
      Parameters:
      contextItemType - the static type of the context item
      Returns:
      the static item type of the expression according to the XSLT 3.0 defined rules

    • getIntrinsicDependencies

      public int getIntrinsicDependencies()
      Description copied from class: Expression
      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 Expression
      Returns:
      an integer containing bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

    • isUpdatingExpression

      public boolean isUpdatingExpression()
      Determine whether this is an updating expression as defined in the XQuery update specification
      Overrides:
      isUpdatingExpression in class Expression
      Returns:
      true if this is an updating expression

    • computeSpecialProperties

      protected int computeSpecialProperties()
      Compute the special properties of this expression. These properties are denoted by a bit-significant integer, possible values are in class StaticProperty. The "special" properties are properties other than cardinality and dependencies, and most of them relate to properties of node sequences, for example whether the nodes are in document order.
      Overrides:
      computeSpecialProperties in class Expression
      Returns:
      the special properties, as a bit-significant integer

    • copy

      public Expression copy(RebindingMap rebindings)
      Copy an expression. This makes a deep copy.
      Specified by:
      copy in class Expression
      Parameters:
      rebindings - variable bindings that need to be changed
      Returns:
      the copy of the original expression

    • computeCardinality

      protected int computeCardinality()
      Determine the cardinality of the result
      Specified by:
      computeCardinality in class Expression
      Returns:
      the computed cardinality, as one of the values StaticProperty.ALLOWS_ZERO_OR_ONE, StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE, StaticProperty.ALLOWS_ZERO_OR_MORE. May also return StaticProperty.ALLOWS_ZERO if the result is known to be an empty sequence, or StaticProperty.ALLOWS_MANY if if is known to return a sequence of length two or more.

    • typeCheck

      public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) 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.
      Overrides:
      typeCheck in class FunctionCall
      Parameters:
      visitor - an expression visitor
      contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.
      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, ContextItemStaticInfo 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.

      Overrides:
      optimize 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 if appropriate to optimize execution
      Throws:
      XPathException - if an error is discovered during this phase (typically a type error)

    • resetLocalStaticProperties

      public void resetLocalStaticProperties()
      Reset the static properties of the expression to -1, so that they have to be recomputed next time they are used.
      Overrides:
      resetLocalStaticProperties in class Expression

    • addToPathMap

      public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
      Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.

      The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.

      Overrides:
      addToPathMap in class Expression
      Parameters:
      pathMap - the PathMap to which the expression should be added
      pathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be added
      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. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.

    • markTailFunctionCalls

      public int markTailFunctionCalls(StructuredQName qName, 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 Expression
      Parameters:
      qName - the name of the function
      arity - the arity (number of parameters) of the function
      Returns:
      NOT_TAIL_CALL if no tail call was found; FOREIGN_TAIL_CALL if a tail call on a different function was found; SELF_TAIL_CALL 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: FunctionCall
      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.
      Overrides:
      getImplementationMethod in class FunctionCall
      Returns:
      the implementation method, for example Expression.ITERATE_METHOD or Expression.EVALUATE_METHOD or Expression.PROCESS_METHOD

    • 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
      Overrides:
      evaluateItem in class FunctionCall
      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)
      Overrides:
      iterate in class FunctionCall
      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(Outputter output, XPathContext context) throws XPathException
      Process the function call in push mode
      Overrides:
      process in class Expression
      Parameters:
      output - the destination for the result
      context - the XPath dynamic context
      Throws:
      XPathException - if a dynamic error occurs

    • getTargetComponent

      public Component getTargetComponent(XPathContext context)

    • getTargetFunction

      public UserFunction getTargetFunction(XPathContext context)
      Description copied from class: FunctionCall
      Get the target function to be called
      Specified by:
      getTargetFunction in class FunctionCall
      Parameters:
      context - the dynamic evaluation context
      Returns:
      the target function

    • evaluateArguments

      public Sequence[] evaluateArguments(XPathContext c, boolean streamed) throws XPathException
      Throws:
      XPathException

    • export

      public void export(ExpressionPresenter out) throws XPathException
      Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
      Specified by:
      export in interface ExportAgent
      Overrides:
      export in class FunctionCall
      Parameters:
      out - the expression presenter used to display the structure
      Throws:
      XPathException - if the export fails, for example if an expression is found that won't work in the target environment.

    • getExpressionName

      public String getExpressionName()
      Get a name identifying the kind of expression, in terms meaningful to a user.
      Overrides:
      getExpressionName in class FunctionCall
      Returns:
      a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.

    • getProperty

      public Object getProperty(String name)
      Overrides:
      getProperty in class Expression

    • getObjectName

      public StructuredQName getObjectName()
      Description copied from interface: Traceable
      Get a name identifying the object of the expression, for example a function name, template name, variable name, key name, element name, etc. This is used only where the name is known statically.
      Specified by:
      getObjectName in interface Traceable
      Overrides:
      getObjectName in class Expression
      Returns:
      the QName of the object declared or manipulated by this instruction or expression

    • getElaborator

      public Elaborator getElaborator()
      Description copied from class: Expression
      Make an elaborator for this expression
      Overrides:
      getElaborator in class Expression
      Returns:
      an appropriate Elaborator