Package org.basex.query.value.item

Class FuncItem

java.lang.Object

org.basex.query.expr.ExprInfo

org.basex.query.expr.Expr

org.basex.query.value.Value

org.basex.query.value.item.Item

org.basex.query.value.item.FItem

org.basex.query.value.item.FuncItem

All Implemented Interfaces:

Iterable<Item>, XQFunction, XQFunctionExpr, Scope

public final class FuncItem
extends FItem
implements Scope

Function item.

Author:

BaseX Team 2005-21, BSD License, Leo Woerteler

Field Summary

Fields

Modifier and Type	Field	Description
final StaticContext	sc	Static context.

Fields inherited from class org.basex.query.value.item.Item

UNDEF

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

type

Constructor Summary

Constructors

Constructor	Description
FuncItem(StaticContext sc, AnnList anns, QNm name, Var[] params, FuncType type, Expr expr, int stackSize, InputInfo info)	Constructor.
FuncItem(StaticContext sc, AnnList anns, QNm name, Var[] params, FuncType type, Expr expr, QueryFocus focus, int stackSize, InputInfo info)	Constructor.

Method Summary

Modifier and Type	Method	Description
boolean	accept(ASTVisitor visitor)	Traverses this expression, notifying the visitor of declared and used variables, and checking the tree for other recursive properties.
int	arity()	Number of arguments this function takes.
Item	atomItem(QueryContext qc, InputInfo ii)	Evaluates the expression and returns the resulting, atomized item, or Empty.VALUE if the expression yields an empty sequence.
Value	atomValue(QueryContext qc, InputInfo ii)	Evaluates the expression and returns the atomized items.
FuncItem	coerceTo(FuncType ft, QueryContext qc, InputInfo ii, boolean optimize)	Coerces this function item to the given function type.
void	comp(CompileContext cc)	Compiles the expression contained in this scope.
boolean	compiled()	Checks if this scope has already been compiled.
boolean	deep(Item item, Collation coll, InputInfo ii)	Performs a deep comparison of two items.
String	description()	Returns a string description of the expression.
boolean	equals(Object obj)	This function is e.g.
QNm	funcName()	Name of this function, null means anonymous function.
Expr	inline(Expr[] exprs, CompileContext cc)	Tries to inline this function with the given arguments.
Value	invokeInternal(QueryContext qc, InputInfo ii, Value[] args)	Internally invokes this function with the given arguments.
Item	materialize(QueryContext qc, boolean copy)	Returns a materialized, context-independent version of this item.
QNm	paramName(int ps)	Name of the parameter at the given position.
void	plan(QueryPlan plan)	Creates a query plan.
void	plan(QueryString qs)	Creates a query string.
int	stackFrameSize()	Size of this function's stack frame.
String	toErrorString()	Returns a string representation of the expression that can be embedded in error messages.
Object	toJava()	Returns a Java representation of the value.
boolean	vacuousBody()	Checks if this function returns vacuous results (see Expr.vacuous()).
boolean	visit(ASTVisitor visitor)	Traverses this scope with the given ASTVisitor.

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

annotations, eq, funcType, refineType, sameKey, string

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

atomSize, bool, cache, comparable, dbl, ddo, dec, diff, ebv, equiv, flt, hash, input, instanceOf, item, itemAt, iter, itr, persistent, reverse, score, seqType, size, subsequence, test, typeId, xdmInfo

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

checkUp, compile, copy, count, exprSize, has, inline, inlineable, isEmpty, isItem, iter, iterator, materialize, serialize, serialize, serialize, value

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

arg, args, atomIter, data, data, hasFreeVars, indexAccessible, isSimple, markTailCalls, mergeEbv, optimize, simplifyFor, typeCheck, uses, vacuous, visitAll

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

toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface org.basex.query.func.XQFunction

invoke, invokeTail

Field Details

sc

public final StaticContext sc

Static context.

Constructor Details

FuncItem

public FuncItem(StaticContext sc,
 AnnList anns,
 QNm name,
 Var[] params,
 FuncType type,
 Expr expr,
 int stackSize,
 InputInfo info)

Constructor.

Parameters:

sc - static context

anns - function annotations

name - function name (may be null)

params - formal parameters

type - function type

expr - function body

stackSize - stack-frame size

info - input info

FuncItem

public FuncItem(StaticContext sc,
 AnnList anns,
 QNm name,
 Var[] params,
 FuncType type,
 Expr expr,
 QueryFocus focus,
 int stackSize,
 InputInfo info)

Constructor.

Parameters:

sc - static context

anns - function annotations

name - function name (may be null)

params - formal parameters

type - function type

expr - function body

focus - query focus (may be null)

stackSize - stack-frame size

info - input info

Method Details

arity

public int arity()

Description copied from interface: XQFunctionExpr

Number of arguments this function takes.

Specified by:

arity in interface XQFunctionExpr

Returns:

function arity

funcName

public QNm funcName()

Description copied from interface: XQFunctionExpr

Name of this function, null means anonymous function.

Specified by:

funcName in interface XQFunctionExpr

Returns:

name or null

paramName

public QNm paramName(int ps)

Description copied from interface: XQFunctionExpr

Name of the parameter at the given position.

Specified by:

paramName in interface XQFunctionExpr

Parameters:

ps - position of the parameter

Returns:

name of the parameter

invokeInternal

public Value invokeInternal(QueryContext qc,
 InputInfo ii,
 Value[] args)
                     throws QueryException

Description copied from interface: XQFunction

Internally invokes this function with the given arguments.

Specified by:

invokeInternal in interface XQFunction

Parameters:

qc - query context

ii - input info

args - arguments

Returns:

resulting value

Throws:

QueryException - query exception

stackFrameSize

public int stackFrameSize()

Description copied from interface: XQFunction

Size of this function's stack frame.

Specified by:

stackFrameSize in interface XQFunction

Returns:

stack frame size

coerceTo

public FuncItem coerceTo(FuncType ft,
 QueryContext qc,
 InputInfo ii,
 boolean optimize)
                  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

qc - query context

ii - input info

optimize - optimize resulting item

Returns:

coerced item

Throws:

QueryException - query exception

accept

public boolean accept(ASTVisitor visitor)

Description copied from class: Expr

Traverses this expression, notifying the visitor of declared and used variables, and checking the tree for other recursive properties.

Overrides:

accept in class Value

Parameters:

visitor - visitor

Returns:

if the walk should be continued

visit

public boolean visit(ASTVisitor visitor)

Description copied from interface: Scope

Traverses this scope with the given ASTVisitor.

Specified by:

visit in interface Scope

Parameters:

visitor - visitor

Returns:

continue flag

comp

public void comp(CompileContext cc)

Description copied from interface: Scope

Compiles the expression contained in this scope.

Specified by:

comp in interface Scope

Parameters:

cc - compilation context

compiled

public boolean compiled()

Description copied from interface: Scope

Checks if this scope has already been compiled.

Specified by:

compiled in interface Scope

Returns:

result of check

toJava

public Object toJava()

Description copied from class: Value

Returns a Java representation of the value.

Specified by:

toJava in class Value

Returns:

Java object

inline

public Expr inline(Expr[] exprs,
 CompileContext cc)
            throws QueryException

Description copied from interface: XQFunctionExpr

Tries to inline this function with the given arguments.

Specified by:

inline in interface XQFunctionExpr

Parameters:

exprs - arguments

cc - compilation context

Returns:

the expression to inline if successful, null otherwise

Throws:

QueryException - query exception

atomValue

public Value atomValue(QueryContext qc,
 InputInfo ii)
                throws QueryException

Description copied from class: Item

Evaluates the expression and returns the atomized items. Overwritten by XQArray, FuncItem and ANode.

Overrides:

atomValue in class Item

Parameters:

qc - query context

ii - input info (only required by Seq instances, which have no input info)

Returns:

atomized item

Throws:

QueryException - query exception

atomItem

public Item atomItem(QueryContext qc,
 InputInfo ii)
              throws QueryException

Description copied from class: Item

Evaluates the expression and returns the resulting, atomized item, or Empty.VALUE if the expression yields an empty sequence. Overwritten by XQArray, FuncItem and ANode.

Overrides:

atomItem in class Item

Parameters:

qc - query context

ii - input info (only required by Seq instances, which have no input info)

Returns:

item or Empty.VALUE

Throws:

QueryException - query exception

materialize

public Item materialize(QueryContext qc,
 boolean copy)

Description copied from class: Item

Returns a materialized, context-independent version of this item.

Overrides:

materialize in class Item

Parameters:

qc - query context (if null, process cannot be interrupted)

copy - create full copy

Returns:

item copy, or null) if the item cannot be materialized

deep

public boolean deep(Item item,
 Collation coll,
 InputInfo ii)
             throws QueryException

Description copied from class: FItem

Performs a deep comparison of two items.

Specified by:

deep in class FItem

Parameters:

item - item to be compared

coll - collation (can be null)

ii - input info

Returns:

result of check

Throws:

QueryException - query exception

vacuousBody

public boolean vacuousBody()

Description copied from interface: XQFunctionExpr

Checks if this function returns vacuous results (see Expr.vacuous()).

Specified by:

vacuousBody in interface XQFunctionExpr

Returns:

result of check

equals

public boolean equals(Object obj)

Description copied from class: Expr

This function is e.g. called by:

• If.optimize(CompileContext), Switch.optimize(CompileContext), Typeswitch.optimize(CompileContext), in order to discard identical expressions.
• CmpR.mergeEbv(Expr, boolean, CompileContext) or CmpSR.mergeEbv(Expr, boolean, CompileContext), in order to merge expressions with identical input.
• CmpG.optimize(CompileContext) or CmpV.optimize(CompileContext), in order to pre-evaluate equality tests.
• CmpG.optimize(CompileContext) or Pos.get(Expr, CmpV.OpV, InputInfo, CompileContext), in order to compare the start and end value.
• PathCache, in order to find identical root values at runtime.

Specified by:

equals in class Expr

description

public String description()

Description copied from class: ExprInfo

Returns a string description of the expression. This method is only called by error messages. Contrary to the ExprInfo.toString() method, arguments are not included in the output.

Overrides:

description in class Item

Returns:

result of check

plan

public void plan(QueryPlan plan)

Description copied from class: ExprInfo

Creates a query plan.

Overrides:

plan in class Item

Parameters:

plan - expression plan

toErrorString

public String toErrorString()

Description copied from class: ExprInfo

Returns a string representation of the expression that can be embedded in error messages. Defaults to ExprInfo.toString().

Overrides:

toErrorString in class ExprInfo

Returns:

class name

plan

public void plan(QueryString qs)

Description copied from class: ExprInfo

Creates a query string.

Specified by:

plan in class ExprInfo

Parameters:

qs - query string builder