net.sf.saxon.functions

Class Sum

java.lang.Object

net.sf.saxon.om.AbstractItem

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

net.sf.saxon.functions.FoldingFunction

net.sf.saxon.functions.Sum

All Implemented Interfaces:

Callable, Function, GroundedValue, Item, Sequence

public class Sum
extends FoldingFunction

Implementation of the fn:sum function

Constructor Summary

Constructors

Constructor and Description
Sum()

Method Summary

Modifier and Type	Method and Description
int	getCardinality(Expression[] arguments) Get the cardinality, given knowledge of the actual arguments
java.lang.String	getCompilerName() Get the (local) name of a class that can be used to generate bytecode for this system function
Fold	getFold(XPathContext context, Sequence... additionalArguments) Create the Fold object which actually performs the evaluation.
ItemType	getResultItemType(Expression[] args) Get the return type, given knowledge of the actual arguments
static AtomicValue	total(SequenceIterator in, XPathContext context, Location locator) Static method to compute a total, invoked from compiled bytecode

Methods inherited from class net.sf.saxon.functions.FoldingFunction

call, getStreamerName

Methods inherited from class net.sf.saxon.functions.SystemFunction

dependsOnContextItem, dynamicCall, equals, export, exportAdditionalArguments, exportAttributes, fixArguments, getArity, getContextNode, getDescription, getDetails, getErrorCodeForTypeErrors, getFunctionItemType, getFunctionName, getIntegerBounds, getNetCost, getOperandRoles, getRequiredType, getResultItemType, getRetainedStaticContext, getSpecialProperties, getStaticBaseUriString, importAttributes, isTrustedResultType, makeCall, makeFunction, makeFunctionCall, makeOptimizedFunctionCall, resultIfEmpty, setArity, setDetails, setRetainedStaticContext, supplyTypeInformation, typeCheckCaller

Methods inherited from class net.sf.saxon.functions.AbstractFunction

atomize, deepEquals, effectiveBooleanValue, getAnnotations, getStringValue, getStringValueCS, isArray, isMap, makeNewContext, simplify, typeCheck

Methods inherited from class net.sf.saxon.om.AbstractItem

getLength, head, isStreamed, itemAt, iterate, reduce, subsequence

Methods inherited from class java.lang.Object

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

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

iterate

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

head

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

getLength, head, itemAt, reduce, subsequence

Constructor Detail

Sum

public Sum()

Method Detail

getResultItemType

public ItemType getResultItemType(Expression[] args)

Description copied from class: SystemFunction

Get the return type, given knowledge of the actual arguments

Overrides:

getResultItemType in class SystemFunction

Parameters:

args - the actual arguments supplied

Returns:

the best available item type that the function will return

getCardinality

public int getCardinality(Expression[] arguments)

Description copied from class: SystemFunction

Get the cardinality, given knowledge of the actual arguments

Overrides:

getCardinality in class SystemFunction

Parameters:

arguments - the actual arguments supplied

Returns:

the most precise available cardinality that the function will return

getFold

public Fold getFold(XPathContext context,
                    Sequence... additionalArguments)
             throws XPathException

Create the Fold object which actually performs the evaluation.

Specified by:

getFold in class FoldingFunction

Parameters:

context - the dynamic evaluation context

additionalArguments - the values of all arguments other than the first.

Returns:

the Fold object used to compute the function

Throws:

XPathException - if a dynamic error occurs

total

public static AtomicValue total(SequenceIterator in,
                                XPathContext context,
                                Location locator)
                         throws XPathException

Static method to compute a total, invoked from compiled bytecode

Parameters:

in - the sequence of items to be summed

context - dynamic context for evaluation

locator - expression location for diagnostics

Returns:

null if the input is empty, otherwise the total as defined by the semantics of the sum() function

Throws:

XPathException - if a dynamic error occurs

getCompilerName

public java.lang.String getCompilerName()

Description copied from class: SystemFunction

Get the (local) name of a class that can be used to generate bytecode for this system function

Overrides:

getCompilerName in class SystemFunction

Returns:

the name of a bytecode generation class, or null if there is no bytecode support for this function