Class UserFunction

java.lang.Object
net.sf.saxon.instruct.Procedure
net.sf.saxon.instruct.UserFunction
All Implemented Interfaces:
Serializable, 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:
  • Constructor Details

    • UserFunction

      public UserFunction()
    • UserFunction

      public UserFunction(Expression body)
  • Method Details

    • computeEvaluationMode

      public void computeEvaluationMode()
    • setParameterDefinitions

      public void setParameterDefinitions(UserFunctionParameter[] params)
    • getParameterDefinitions

      public UserFunctionParameter[] getParameterDefinitions()
    • 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