org.basex.query.xpath.func
Class Last

java.lang.Object
  org.basex.query.ExprInfo
      org.basex.query.xpath.expr.Expr
          org.basex.query.xpath.func.Func
              org.basex.query.xpath.func.Last

public final class Last
extends Func

Constructor for last() function.

Author:

Workgroup DBIS, University of Konstanz 2005-08, ISC License, Tim Petrowsky

Field Summary

Fields inherited from class org.basex.query.xpath.func.Func

desc

Constructor Summary

Last(Expr[] arg)
Function Constructor.

Method Summary

boolean	checkArguments() Checks validity/number of arguments.
Dbl	eval(XPContext ctx) Evaluates the expression with the specified context set.
boolean	usesSize() Checks whether this Expression (or its children) make use of the setsize parameter.

Methods inherited from class org.basex.query.xpath.func.Func

comp, evalArgs, plan, toString, usesPos

Methods inherited from class org.basex.query.xpath.expr.Expr

indexEquivalent, indexSizes, returnedValue, sameAs

Methods inherited from class org.basex.query.ExprInfo

color, info, name

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Last

public Last(Expr[] arg)

Function Constructor.

Parameters:

arg - expression array

Method Detail

eval

public Dbl eval(XPContext ctx)
         throws QueryException

Description copied from class: Expr

Evaluates the expression with the specified context set. Additionally provides a context

Specified by:

eval in class Expr

Parameters:

ctx - query context

Returns:

resulting XPathValue

Throws:

QueryException - evaluation exception

checkArguments

public boolean checkArguments()

Description copied from class: Func

Checks validity/number of arguments.

Specified by:

checkArguments in class Func

Returns:

result of comparison

usesSize

public boolean usesSize()

Description copied from class: Expr

Checks whether this Expression (or its children) make use of the setsize parameter. If not this allows early predicate evaluation.

Overrides:

usesSize in class Func

Returns:

whether setsize is used