org.basex.query.func

Class FNSimple

java.lang.Object

org.basex.data.ExprInfo

org.basex.query.expr.Expr

org.basex.query.expr.ParseExpr

org.basex.query.expr.Arr

org.basex.query.func.StandardFunc

org.basex.query.func.FNSimple

public final class FNSimple
extends StandardFunc

Simple functions.

Author:

BaseX Team 2005-12, BSD 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.expr.Arr

expr

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

input, size, type

Constructor Summary

Constructors

Constructor and Description
FNSimple(InputInfo ii, Function f, Expr... e) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
Expr	cmp(QueryContext ctx) Performs function specific compilations.
Expr	compEbv(QueryContext ctx) This method is called at compile time by expressions that perform effective boolean value tests (e.g.
Item	item(QueryContext ctx, InputInfo ii) Evaluates the expression and returns the resulting item or a null reference, if the expression yields an empty sequence.
Iter	iter(QueryContext ctx) Evaluates the expression and returns an iterator on the resulting items.
Value	value(QueryContext ctx) Evaluates the expression and returns the resulting value.

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

atom, comp, description, isFunction, plan, toString

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

allAreValues, count, indexEquivalent, removable, remove, toString, uses

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

checkBln, checkColl, checkCreate, checkCtx, checkDbl, checkDBNode, checkEStr, checkEStr, checkIO, checkItem, checkItr, checkItr, checkMap, checkNode, checkNoEmpty, checkStr, checkType, checkUp, checkUp, checkWrite, compBln, ebv, optPre, preEval, size, test, type

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

addText, hasFreeVars, indexAccessible, isEmpty, isItem, isVacuous, isValue, iterable, markTailCalls, sameAs

Methods inherited from class org.basex.data.ExprInfo

info

Methods inherited from class java.lang.Object

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

Constructor Detail

FNSimple

public FNSimple(InputInfo ii,
        Function f,
        Expr... e)

Constructor.

Parameters:

ii - input info

f - function definition

e - arguments

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.item(org.basex.query.QueryContext, org.basex.util.InputInfo) must be implemented by an expression, as it may be called by this method.

Overrides:

iter in class ParseExpr

Parameters:

ctx - query context

Returns:

resulting item

Throws:

QueryException - query exception

value

public Value value(QueryContext ctx)
            throws QueryException

Description copied from class: Expr

Evaluates the expression and returns the resulting value.

Overrides:

value in class ParseExpr

Parameters:

ctx - query context

Returns:

iterator

Throws:

QueryException - query exception

item

public Item item(QueryContext ctx,
        InputInfo ii)
          throws QueryException

Description copied from class: Expr

Evaluates the expression and returns the resulting item or a null reference, if the expression yields an empty sequence. If this method is not overwritten, Expr.iter(org.basex.query.QueryContext) must be implemented by an expression, as it may be called by this method.

Overrides:

item in class ParseExpr

Parameters:

ctx - query context

ii - input info

Returns:

iterator

Throws:

QueryException - query exception

cmp

public Expr cmp(QueryContext ctx)

Description copied from class: StandardFunc

Performs function specific compilations.

Parameters:

ctx - query context

Returns:

evaluated item

compEbv

public Expr compEbv(QueryContext ctx)

Description copied from class: Expr

This method is called at compile time by expressions that perform effective boolean value tests (e.g. If or Preds). If the arguments of the called expression return a boolean anyway, the expression will be simplified.

Example in CmpV: if($x eq true()) is rewritten to if($x), if $x will always yield a single boolean.

Overrides:

compEbv in class Expr

Parameters:

ctx - query context

Returns:

optimized expression