org.basex.query.func
Class FNGen

java.lang.Object
  org.basex.query.ExprInfo
      org.basex.query.expr.Expr
          org.basex.query.expr.Arr
              org.basex.query.func.Fun
                  org.basex.query.func.FNGen

public final class FNGen
extends Fun

Generating functions.

Author:

Workgroup DBIS, University of Konstanz 2005-10, ISC License, Christian Gruen

Nested Class Summary

Nested classes/interfaces inherited from class org.basex.query.expr.Expr

Expr.Use

Field Summary

Fields inherited from class org.basex.query.func.Fun

func

Fields inherited from class org.basex.query.expr.Arr

expr

Constructor Summary

FNGen()

Method Summary

Item	atomic(QueryContext ctx) Evaluates the expression and returns the resulting item or a null reference.
Expr	c(QueryContext ctx) Compiles the function.
Iter	iter(QueryContext ctx) Evaluates the expression and returns an iterator on the resulting items.
boolean	uses(Expr.Use u, QueryContext ctx) Indicates if an expression uses the specified type.

Methods inherited from class org.basex.query.func.Fun

comp, info, init, plan, returned, toString

Methods inherited from class org.basex.query.expr.Arr

duplicates, indexEquivalent, removable, remove

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

addText, checkCtx, checkDbl, checkItr, e, ebv, i, indexAccessible, sameAs, size, test, v

Methods inherited from class org.basex.query.ExprInfo

color, name

Methods inherited from class java.lang.Object

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

Constructor Detail

FNGen

public FNGen()

Method Detail

iter

public Iter iter(QueryContext ctx)
          throws QueryException

Description copied from class: Expr

Evaluates the expression and returns an iterator on the resulting items. If this method is not overwritten, Expr.atomic(org.basex.query.QueryContext) must be implemented.

Overrides:

iter in class Expr

Parameters:

ctx - query context

Returns:

resulting item

Throws:

QueryException - query exception

atomic

public Item atomic(QueryContext ctx)
            throws QueryException

Description copied from class: Expr

Evaluates the expression and returns the resulting item or a null reference. If this method is not overwritten, Expr.iter(org.basex.query.QueryContext) must be implemented.

Overrides:

atomic in class Expr

Parameters:

ctx - query context

Returns:

iterator

Throws:

QueryException - query exception

c

public Expr c(QueryContext ctx)
       throws QueryException

Description copied from class: Fun

Compiles the function.

Overrides:

c in class Fun

Parameters:

ctx - query context

Returns:

evaluated item

Throws:

QueryException - query exception

uses

public boolean uses(Expr.Use u,
                    QueryContext ctx)

Description copied from class: Expr

Indicates if an expression uses the specified type. Called by the compiler to perform certain optimizations. true is returned by default and thus assumed as "worst-case".

Overrides:

uses in class Arr

Parameters:

u - use type to be checked

ctx - query context

Returns:

result of check