org.basex.query.xpath.func
Class Last

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