Package net.sf.saxon.instruct

Class UserFunction

  • All Implemented Interfaces:
    java.io.Serializable, javax.xml.transform.SourceLocator, LocationProvider, Container, InstructionInfoProvider
    public final class UserFunction
extends Procedure
implements InstructionInfoProvider
    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

    • Constructor Detail

      • UserFunction

        public UserFunction()

      • UserFunction

        public UserFunction​(Expression body)

    • Method Detail

      • computeEvaluationMode

        public void computeEvaluationMode()

      • setResultType

        public void setResultType​(SequenceType resultType)

      • setTailRecursive

        public void setTailRecursive​(boolean tailCalls)

      • isTailRecursive

        public boolean isTailRecursive()

      • getResultType

        public SequenceType getResultType()
        Get the type of value returned by this function
        Returns:
        the declared result type, or the inferred result type if this is more precise

      • 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

      • getNumberOfArguments

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

      • setMemoFunction

        public void setMemoFunction​(boolean isMemo)
        Mark this function as a memo function (or not)
        Parameters:
        isMemo - true if this is a memo function

      • setFunctionNameCode

        public void setFunctionNameCode​(int nameCode)
        Set the namepool name code of the function
        Parameters:
        nameCode - represents the function name

      • getFunctionNameCode

        public int getFunctionNameCode()
        Get the namepool name code of the function
        Returns:
        a name code representing the function name

      • 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

      • 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

      • 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

      • getInstructionInfo

        public InstructionInfo getInstructionInfo()
        Get the InstructionInfo details about the construct. This information isn't used for tracing, but it is available when inspecting the context stack.
        Specified by:
        getInstructionInfo in interface InstructionInfoProvider