com.saxonica.expr
Class MemoFunction

java.lang.Object
  net.sf.saxon.expr.instruct.Procedure
      net.sf.saxon.expr.instruct.UserFunction
          com.saxonica.expr.MemoFunction

All Implemented Interfaces:

Serializable, SourceLocator, LocationProvider, SaxonLocator, Container, InstructionInfo, Locator

public class MemoFunction
extends UserFunction

A user-defined function that is declared as a memo function, meaning that it remembers results of previous calls.

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.expr.instruct.UserFunction

evaluationMode

Fields inherited from class net.sf.saxon.expr.instruct.Procedure

body

Constructor Summary

MemoFunction()

Method Summary

ValueRepresentation	call(ValueRepresentation[] actualArgs, XPathContextMajor context) Call this function to return a value.
void	computeEvaluationMode() Determine the preferred evaluation mode for this function
boolean	isMemoFunction() Ask whether this function is a memo function

Methods inherited from class net.sf.saxon.expr.instruct.UserFunction

call, callUpdating, containsTailCalls, gatherDirectContributingCallees, getArgumentType, getConstructType, getDeclaredResultType, getEvaluationMode, getFunctionName, getNumberOfArguments, getObjectName, getParameterDefinitions, getResultType, isInlineable, isTailRecursive, isUpdating, iterateEvents, process, setFunctionName, setInlineable, setParameterDefinitions, setResultType, setTailRecursive, setUpdating

Methods inherited from class net.sf.saxon.expr.instruct.Procedure

getBody, getColumnNumber, getColumnNumber, getContainerGranularity, getExecutable, getHostLanguage, getLineNumber, getLineNumber, getLocationProvider, getProperties, getProperty, getPublicId, getStackFrameMap, getSystemId, getSystemId, setBody, setExecutable, setHostLanguage, setLineNumber, setStackFrameMap, setSystemId

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MemoFunction

public MemoFunction()

Method Detail

computeEvaluationMode

public void computeEvaluationMode()

Determine the preferred evaluation mode for this function

Overrides:

computeEvaluationMode in class UserFunction

isMemoFunction

public boolean isMemoFunction()

Ask whether this function is a memo function

Overrides:

isMemoFunction in class UserFunction

Returns:

true if this function is marked as a memo function

call

public ValueRepresentation call(ValueRepresentation[] actualArgs,
                                XPathContextMajor context)
                         throws XPathException

Call this function to return a value.

Overrides:

call in class UserFunction

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