org.basex.query.xpath.func
Class Position

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

public final class Position
extends Func

Constructor for position() function.

Author:

Workgroup DBIS, University of Konstanz 2005-07, ISC License, Tim Petrowsky

Field Summary

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

desc

Constructor Summary

Position(Expr[] arg)
Function Constructor.

Method Summary

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

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

compile, evalArgs, toString, usesSize

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

indexEquivalent, indexSizes, returnedValue, sameAs

Methods inherited from class java.lang.Object

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

Constructor Detail

Position

public Position(Expr[] arg)

Function Constructor.

Parameters:

arg - expression array

Method Detail

checkArguments

public boolean checkArguments()

Description copied from class: Func

Checks validity/number of arguments.

Specified by:

checkArguments in class Func

Returns:

result of comparison

eval

public Num eval(XPContext ctx)
         throws EvalException

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:

EvalException - evaluation exception

usesPos

public boolean usesPos()

Description copied from class: Expr

Checks whether this Expression (or its children) make use of the position parameter. If not this allows some nice optimizations.

Overrides:

usesPos in class Func

Returns:

whether position is used