org.basex.query.expr
Class Arr

java.lang.Object
  org.basex.query.ExprInfo
      org.basex.query.expr.Expr
          org.basex.query.expr.Arr

Direct Known Subclasses:

And, CFrag, Clc, CmpG, CmpN, CmpV, Except, Fun, FunCall, FunJava, If, InterSect, List, Or, Range, Transform, Union, Update

public abstract class Arr
extends Expr

Abstract array expression.

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

Expr[]

expr Expression list.

Method Summary

Expr	comp(QueryContext ctx) Optimizes and compiles the expression.
boolean	duplicates(QueryContext ctx) Returns true if the expression might yield duplicates and unsorted results.
Expr	indexEquivalent(IndexContext ic) Returns an equivalent expression which accesses an index structure.
void	plan(Serializer ser) Recursively sends the abstract syntax of this expression to the specified serializer.
boolean	removable(Var v, QueryContext ctx) Checks if the specified variable is removable.
Expr	remove(Var v) Removes the specified variable in a sub expression.
boolean	uses(Expr.Use u, QueryContext ctx) Indicates if an expression uses the specified type.

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

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

Methods inherited from class org.basex.query.ExprInfo

color, info, name, toString

Methods inherited from class java.lang.Object

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

Field Detail

expr

public Expr[] expr

Expression list.

Method Detail

comp

public Expr comp(QueryContext ctx)
          throws QueryException

Description copied from class: Expr

Optimizes and compiles the expression.

Specified by:

comp in class Expr

Parameters:

ctx - query context

Returns:

optimized Expression

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".

Specified by:

uses in class Expr

Parameters:

u - use type to be checked

ctx - query context

Returns:

result of check

removable

public boolean removable(Var v,
                         QueryContext ctx)

Description copied from class: Expr

Checks if the specified variable is removable.

Overrides:

removable in class Expr

Parameters:

v - variable to be removed

ctx - query context

Returns:

result of check

remove

public Expr remove(Var v)

Description copied from class: Expr

Removes the specified variable in a sub expression.

Overrides:

remove in class Expr

Parameters:

v - variable to be removed

Returns:

expression with removed variable

indexEquivalent

public Expr indexEquivalent(IndexContext ic)
                     throws QueryException

Description copied from class: Expr

Returns an equivalent expression which accesses an index structure. Must be called if Expr.indexAccessible(org.basex.query.IndexContext) is implemented for an expression.

Overrides:

indexEquivalent in class Expr

Parameters:

ic - index context

Returns:

Equivalent index-expression or null

Throws:

QueryException - query exception

duplicates

public boolean duplicates(QueryContext ctx)

Description copied from class: Expr

Returns true if the expression might yield duplicates and unsorted results.

Overrides:

duplicates in class Expr

Parameters:

ctx - query context

Returns:

result of check

plan

public void plan(Serializer ser)
          throws IOException

Description copied from class: ExprInfo

Recursively sends the abstract syntax of this expression to the specified serializer.

Specified by:

plan in class ExprInfo

Parameters:

ser - serializer

Throws:

IOException - I/O exception