org.treetank.service.xml.xpath.functions.sequences

Class FNSum

java.lang.Object

org.treetank.axis.AbsAxis

org.treetank.service.xml.xpath.expr.AbsExpression

org.treetank.service.xml.xpath.functions.AbsFunction

org.treetank.service.xml.xpath.functions.sequences.FNSum

All Implemented Interfaces:

Iterable<Long>, Iterator<Long>

public class FNSum
extends AbsFunction

FNSum

IAxis that represents the function fn:sum specified in XQuery 1.0 and XPath 2.0 Functions and Operators.

The function returns the sum of all input item values.

Constructor Summary

Constructors

Constructor and Description
FNSum(INodeReadTrx rtx, List<AbsAxis> args, int min, int max, int returnType) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
protected byte[]	computeResult() Computes the result value of the function.

Methods inherited from class org.treetank.service.xml.xpath.functions.AbsFunction

evaluate, getArgs, reset, varifyParam

Methods inherited from class org.treetank.service.xml.xpath.expr.AbsExpression

hasNext

Methods inherited from class org.treetank.axis.AbsAxis

addAtomicToItemList, close, getItemList, getNode, getStartKey, isSelfIncluded, iterator, moveTo, next, remove, resetToLastKey, resetToStartKey

Methods inherited from class java.lang.Object

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

Constructor Detail

FNSum

public FNSum(INodeReadTrx rtx,
     List<AbsAxis> args,
     int min,
     int max,
     int returnType)
      throws TTXPathException

Constructor. Initializes internal state and do a statical analysis concerning the function's arguments.

Parameters:

rtx - Transaction to operate on

args - List of function arguments

min - min number of allowed function arguments

max - max number of allowed function arguments

returnType - the type that the function's result will have

Throws:

TTXPathException - if function check fails

Method Detail

computeResult

protected byte[] computeResult()

Computes the result value of the function. This implementation is acts as a hook operation and needs to be overridden by the concrete function classes, otherwise an exception is thrown.

Specified by:

computeResult in class AbsFunction

Returns:

value of the result