Package net.sf.saxon.expr.instruct

Class MemoFunction

java.lang.Object

net.sf.saxon.expr.instruct.Actor

net.sf.saxon.expr.instruct.UserFunction

net.sf.saxon.expr.instruct.MemoFunction

All Implemented Interfaces:

javax.xml.transform.SourceLocator, Callable, ContextOriginator, ExpressionOwner, Locatable, Function, GroundedValue, Item, Sequence, Location, Traceable, TraceableComponent, org.xml.sax.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.

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.saxon.expr.instruct.UserFunction

UserFunction.Determinism

Field Summary

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

evaluator

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

body

Constructor Summary

Constructors

Constructor	Description
MemoFunction()

Method Summary

Modifier and Type	Method	Description
Sequence	call(XPathContext context, Sequence[] actualArgs)	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

acceptsNodesWithoutAtomization, atomize, call, callUpdating, containsTailCalls, deepEquals, effectiveBooleanValue, export, gatherProperties, getAnnotations, getArgumentType, getArity, getDeclaredResultType, getDeclaredStreamability, getDescription, getDeterminism, getEvaluator, getFunctionItemType, getFunctionName, getLength, getObjectName, getOperandRoles, getParameterDefinitions, getReferenceCount, getResultType, getSerialNumber, getSymbolicName, getTracingTag, getUnicodeStringValue, head, incrementReferenceCount, isArray, isExportable, isInlineable, isMap, isOverrideExtensionFunction, isTailRecursive, isTrustedResultType, isUpdating, itemAt, makeNewContext, markAsInlined, prepareForStreaming, process, reduce, setAnnotations, setDeclaredStreamability, setDeterminism, setEvaluator, setFunctionName, setInlineable, setOverrideExtensionFunction, setParameterDefinitions, setResultType, setTailRecursive, setUpdating, subsequence, typeCheck

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

allocateAllBindingSlots, allocateBindingSlotsRecursive, getBody, getChildExpression, getColumnNumber, getComponentName, getDeclaredVisibility, getDeclaringComponent, getLineNumber, getLocation, getPackageData, getProperty, getPublicId, getRetainedStaticContext, getStackFrameMap, getSystemId, makeDeclaringComponent, obtainDeclaringComponent, saveLocation, setBody, setChildExpression, setColumnNumber, setDeclaredVisibility, setDeclaringComponent, setLineNumber, setPackageData, setRetainedStaticContext, setStackFrameMap, setSystemId

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.om.Function

getGenre, isSequenceVariadic, toShortString

Methods inherited from interface net.sf.saxon.om.GroundedValue

asIterable, concatenate, containsNode, materialize

Methods inherited from interface net.sf.saxon.om.Item

getStringValue, isStreamed, iterate

Methods inherited from interface net.sf.saxon.expr.Locatable

getLocation

Methods inherited from interface net.sf.saxon.om.Sequence

makeRepeatable

Methods inherited from interface net.sf.saxon.trace.TraceableComponent

getBody, setBody

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 Sequence call(XPathContext context,
                     Sequence[] actualArgs)
              throws XPathException

Call this function to return a value.

Specified by:

call in interface Callable

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