org.basex.query.item

Class FuncItem

java.lang.Object

org.basex.data.ExprInfo

org.basex.query.expr.Expr

org.basex.query.item.Value

org.basex.query.item.Item

org.basex.query.item.FItem

org.basex.query.item.FuncItem

All Implemented Interfaces:

java.lang.Iterable<Item>

public final class FuncItem
extends FItem

Function item.

Author:

BaseX Team 2005-12, BSD License, Leo Woerteler

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.item.Item

UNDEF

Fields inherited from class org.basex.query.item.Value

type

Constructor Summary

Constructors

Constructor and Description
FuncItem(QNm n, Var[] arg, Expr body, FuncType t, boolean cst) Constructor.
FuncItem(Var[] arg, Expr body, FuncType t, VarStack cl, boolean cst) Constructor for anonymous functions.

Method Summary

Methods

Modifier and Type	Method and Description
int	arity() Number of arguments this function item takes.
FItem	coerceTo(FuncType ft, QueryContext ctx, InputInfo ii) Coerces this function item to the given function type.
int	count(Var v) Counts how often the specified variable is used by an expression.
QNm	fName() Name of this function, null means anonymous function.
Item	invItem(QueryContext ctx, InputInfo ii, Value... args) Invokes this function item with the given arguments.
Iter	invIter(QueryContext ctx, InputInfo ii, Value... args) Invokes this function item with the given arguments.
Value	invValue(QueryContext ctx, InputInfo ii, Value... args) Invokes this function item with the given arguments.
void	plan(Serializer ser) Serializes the expression tree.
java.lang.String	toString()
boolean	uses(Expr.Use u) Indicates if an expression uses the specified type or operation.

Methods inherited from class org.basex.query.item.FItem

eq, string, toJava

Methods inherited from class org.basex.query.item.Item

bool, comparable, dbl, dec, diff, ebv, equiv, flt, hash, homogenous, input, isItem, item, itemAt, iter, iterable, itr, score, score, serialize, size, test, type, writeTo, xdmInfo

Methods inherited from class org.basex.query.item.Value

cache, comp, data, description, info, isValue, iter, iterator, removable, remove, value

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

addText, compEbv, hasFreeVars, indexAccessible, indexEquivalent, isEmpty, isFunction, isVacuous, markTailCalls, sameAs

Methods inherited from class java.lang.Object

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

Constructor Detail

FuncItem

public FuncItem(QNm n,
        Var[] arg,
        Expr body,
        FuncType t,
        boolean cst)

Constructor.

Parameters:

n - function name

arg - function arguments

body - function body

t - function type

cst - cast flag

FuncItem

public FuncItem(Var[] arg,
        Expr body,
        FuncType t,
        VarStack cl,
        boolean cst)

Constructor for anonymous functions.

Parameters:

arg - function arguments

body - function body

t - function type

cl - variables in the closure

cst - cast flag

Method Detail

arity

public int arity()

Description copied from class: FItem

Number of arguments this function item takes.

Specified by:

arity in class FItem

Returns:

function arity

fName

public QNm fName()

Description copied from class: FItem

Name of this function, null means anonymous function.

Specified by:

fName in class FItem

Returns:

name or null

invValue

public Value invValue(QueryContext ctx,
             InputInfo ii,
             Value... args)
               throws QueryException

Description copied from class: FItem

Invokes this function item with the given arguments.

Specified by:

invValue in class FItem

Parameters:

ctx - query context

ii - input info

args - arguments

Returns:

resulting iterator

Throws:

QueryException - query exception

invIter

public Iter invIter(QueryContext ctx,
           InputInfo ii,
           Value... args)
             throws QueryException

Description copied from class: FItem

Invokes this function item with the given arguments.

Overrides:

invIter in class FItem

Parameters:

ctx - query context

ii - input info

args - arguments

Returns:

resulting iterator

Throws:

QueryException - query exception

invItem

public Item invItem(QueryContext ctx,
           InputInfo ii,
           Value... args)
             throws QueryException

Description copied from class: FItem

Invokes this function item with the given arguments.

Overrides:

invItem in class FItem

Parameters:

ctx - query context

ii - input info

args - arguments

Returns:

resulting item

Throws:

QueryException - query exception

toString

public java.lang.String toString()

Specified by:

toString in class ExprInfo

uses

public boolean uses(Expr.Use u)

Description copied from class: Expr

Indicates if an expression uses the specified type or operation. This method is called by numerous Expr.comp(org.basex.query.QueryContext) methods to test the properties of sub-expressions. It will return true as soon as at least one test is successful.

Overrides:

uses in class Value

Parameters:

u - type/operation to be found

Returns:

result of check

count

public int count(Var v)

Description copied from class: Expr

Counts how often the specified variable is used by an expression. This method is called by:

• GFLWOR.comp(org.basex.query.QueryContext) to rewrite where clauses as predicates and remove statically bound or unused clauses
• GFLWOR.compHoist(org.basex.query.QueryContext) to hoist independent variables

Overrides:

count in class Value

Parameters:

v - variable to be checked

Returns:

number of occurrences

coerceTo

public FItem coerceTo(FuncType ft,
             QueryContext ctx,
             InputInfo ii)
               throws QueryException

Description copied from class: FItem

Coerces this function item to the given function type.

Specified by:

coerceTo in class FItem

Parameters:

ft - function type

ctx - query context

ii - input info

Returns:

coerced item

Throws:

QueryException - query exception

plan

public void plan(Serializer ser)
          throws java.io.IOException

Description copied from class: ExprInfo

Serializes the expression tree.

Specified by:

plan in class FItem

Parameters:

ser - serializer

Throws:

java.io.IOException - I/O exception