Class UserFunction

  • All Implemented Interfaces:
    java.io.Serializable, javax.xml.transform.SourceLocator, LocationProvider, SaxonLocator, Container, InstructionInfo, org.xml.sax.Locator

    public class UserFunction
    extends Procedure
    This object represents the compiled form of a user-written function (the source can be either an XSLT stylesheet function or an XQuery function).

    It is assumed that type-checking, of both the arguments and the results, has been handled at compile time. That is, the expression supplied as the body of the function must be wrapped in code to check or convert the result to the required type, and calls on the function must be wrapped at compile time to check or convert the supplied arguments.

    See Also:
    Serialized Form
    • Field Detail

      • evaluationMode

        protected int evaluationMode
    • Constructor Detail

      • UserFunction

        public UserFunction()
        Create a user-defined function (the body must be added later)
    • Method Detail

      • setFunctionName

        public void setFunctionName​(StructuredQName name)
        Set the function name
        Parameters:
        name - the function name
      • getFunctionName

        public StructuredQName getFunctionName()
        Get the function name
        Returns:
        the function name, as a StructuredQName
      • getObjectName

        public StructuredQName getObjectName()
        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.
        Returns:
        the QName of the object declared or manipulated by this instruction or expression
      • computeEvaluationMode

        public void computeEvaluationMode()
        Determine the preferred evaluation mode for this function
      • isInlineable

        public java.lang.Boolean isInlineable()
        Ask whether the function can be inlined
        Returns:
        true (yes), false (no), or null (don't know)
      • setInlineable

        public void setInlineable​(boolean inlineable)
        Say whether this function can be inlined
        Parameters:
        inlineable - true or false
      • setParameterDefinitions

        public void setParameterDefinitions​(UserFunctionParameter[] params)
        Set the definitions of the declared parameters for this function
        Parameters:
        params - an array of parameter definitions
      • getParameterDefinitions

        public UserFunctionParameter[] getParameterDefinitions()
        Get the definitions of the declared parameters for this function
        Returns:
        an array of parameter definitions
      • setResultType

        public void setResultType​(SequenceType resultType)
        Set the declared result type of the function
        Parameters:
        resultType - the declared return type
      • setTailRecursive

        public void setTailRecursive​(boolean tailCalls,
                                     boolean recursiveTailCalls)
        Indicate whether the function contains a tail call
        Parameters:
        tailCalls - true if the function contains a tail call (on any function)
        recursiveTailCalls - true if the function contains a tail call (on itself)
      • containsTailCalls

        public boolean containsTailCalls()
        Determine whether the function contains tail calls (on this or other functions)
        Returns:
        true if the function contains tail calls
      • isTailRecursive

        public boolean isTailRecursive()
        Determine whether the function contains a tail call, calling itself
        Returns:
        true if the function contains a directly-recursive tail call
      • setUpdating

        public void setUpdating​(boolean isUpdating)
        Set whether this is an updating function (as defined in XQuery Update)
        Parameters:
        isUpdating - true if this is an updating function
      • isUpdating

        public boolean isUpdating()
        Ask whether this is an updating function (as defined in XQuery Update)
        Returns:
        true if this is an updating function
      • getResultType

        public SequenceType getResultType​(TypeHierarchy th)
        Get the type of value returned by this function
        Parameters:
        th - the type hierarchy cache
        Returns:
        the declared result type, or the inferred result type if this is more precise
      • getDeclaredResultType

        public SequenceType getDeclaredResultType()
        Get the declared result type
        Returns:
        the declared result type
      • getArgumentType

        public SequenceType getArgumentType​(int n)
        Get the required types of an argument to this function
        Parameters:
        n - identifies the argument in question, starting at 0
        Returns:
        a SequenceType object, indicating the required type of the argument
      • getEvaluationMode

        public int getEvaluationMode()
        Get the evaluation mode. The evaluation mode will be computed if this has not already been done
        Returns:
        the computed evaluation mode
      • getNumberOfArguments

        public int getNumberOfArguments()
        Get the arity of this function
        Returns:
        the number of arguments
      • isMemoFunction

        public boolean isMemoFunction()
        Ask whether this function is a memo function
        Returns:
        false (overridden in a subclass)
      • gatherDirectContributingCallees

        public void gatherDirectContributingCallees​(java.util.Set<UserFunction> result)
        Gather the direct contributing callees of this function. A callee is a function that this one calls. A contributing callee is a function whose output is added directly to the output of this function without further processing (other than by attaching it to a parent element or document node). A direct contributing callee is a function that is called directly, rather than indirectly.
        Parameters:
        result - the list into which the callees are gathered.
      • call

        public ValueRepresentation call​(ValueRepresentation[] actualArgs,
                                        XPathContextMajor context)
                                 throws XPathException
        Call this function to return a value.
        Parameters:
        actualArgs - the arguments supplied to the function. These must have the correct types required by the function signature (it is the caller's responsibility to check this). It is acceptable to supply a Closure to represent a value whose evaluation will be delayed until it is needed. The array must be the correct size to match the number of arguments: again, it is the caller's responsibility to check this.
        context - This provides the run-time context for evaluating the function. It is the caller's responsibility to allocate a "clean" context for the function to use; the context that is provided will be overwritten by the function.
        Returns:
        a Value representing the result of the function.
        Throws:
        XPathException - if a dynamic error occurs while evaluating the function
      • process

        public void process​(ValueRepresentation[] actualArgs,
                            XPathContextMajor context)
                     throws XPathException
        Call this function in "push" mode, writing the results to the current output destination.
        Parameters:
        actualArgs - the arguments supplied to the function. These must have the correct types required by the function signature (it is the caller's responsibility to check this). It is acceptable to supply a Closure to represent a value whose evaluation will be delayed until it is needed. The array must be the correct size to match the number of arguments: again, it is the caller's responsibility to check this.
        context - This provides the run-time context for evaluating the function. It is the caller's responsibility to allocate a "clean" context for the function to use; the context that is provided will be overwritten by the function.
        Throws:
        XPathException - if a dynamic error occurs while evaluating the function
      • iterateEvents

        public EventIterator iterateEvents​(ValueRepresentation[] actualArgs,
                                           XPathContextMajor context)
                                    throws XPathException
        Call this function in "pull" mode, returning the results as a sequence of PullEvents.
        Parameters:
        actualArgs - the arguments supplied to the function. These must have the correct types required by the function signature (it is the caller's responsibility to check this). It is acceptable to supply a Closure to represent a value whose evaluation will be delayed until it is needed. The array must be the correct size to match the number of arguments: again, it is the caller's responsibility to check this.
        context - This provides the run-time context for evaluating the function. It is the caller's responsibility to allocate a "clean" context for the function to use; the context that is provided will be overwritten by the function.
        Returns:
        an iterator over the results of the function call
        Throws:
        XPathException - if a dynamic error occurs while evaluating the function
      • call

        public ValueRepresentation call​(ValueRepresentation[] actualArgs,
                                        Controller controller)
                                 throws XPathException
        Call this function. This method allows an XQuery function to be called directly from a Java application. It creates the environment needed to achieve this
        Parameters:
        actualArgs - the arguments supplied to the function. These must have the correct types required by the function signature (it is the caller's responsibility to check this). It is acceptable to supply a Closure to represent a value whose evaluation will be delayed until it is needed. The array must be the correct size to match the number of arguments: again, it is the caller's responsibility to check this.
        controller - This provides the run-time context for evaluating the function. A Controller may be obtained by calling XQueryExpression.newController(). This may be used for a series of calls on functions defined in the same module as the XQueryExpression.
        Returns:
        a Value representing the result of the function.
        Throws:
        XPathException - if a dynamic error occurs while evaluating the function.
      • callUpdating

        public void callUpdating​(ValueRepresentation[] actualArgs,
                                 XPathContextMajor context,
                                 PendingUpdateList pul)
                          throws XPathException
        Call an updating function.
        Parameters:
        actualArgs - the arguments supplied to the function. These must have the correct types required by the function signature (it is the caller's responsibility to check this). It is acceptable to supply a Closure to represent a value whose evaluation will be delayed until it is needed. The array must be the correct size to match the number of arguments: again, it is the caller's responsibility to check this.
        context - the dynamic evaluation context
        pul - the pending updates list, to which the function's update actions are to be added.
        Throws:
        XPathException - if a dynamic error occurs while evaluating the function.
      • getConstructType

        public int getConstructType()
        Get the type of construct. This will either be the fingerprint of a standard XSLT instruction name (values in StandardNames: all less than 1024) or it will be a constant in class Location.
        Returns:
        an integer identifying the kind of construct