org.basex.query.expr
Class VarCall

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

public final class VarCall
extends Expr

Variable 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

Var	var Variable name.

Constructor Summary

VarCall(Var v)
Constructor.

Method Summary

String	color() Returns a color string for the expression.
Expr	comp(QueryContext ctx) Optimizes and compiles the expression.
String	info() Returns a string description of the expression.
Iter	iter(QueryContext ctx) Evaluates the expression and returns an iterator on the resulting items.
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.
Return	returned(QueryContext ctx) Indicates the return type of an expression.
String	toString()
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, duplicates, e, ebv, i, indexAccessible, indexEquivalent, sameAs, size, test, v

Methods inherited from class org.basex.query.ExprInfo

name

Methods inherited from class java.lang.Object

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

Field Detail

var

public Var var

Variable name.

Constructor Detail

VarCall

public VarCall(Var v)

Constructor.

Parameters:

v - variable

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

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

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

returned

public Return returned(QueryContext ctx)

Description copied from class: Expr

Indicates the return type of an expression. Called by the compiler to check if expressions can be reformulated. null is returned by default.

Overrides:

returned 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

color

public String color()

Description copied from class: ExprInfo

Returns a color string for the expression.

Overrides:

color in class ExprInfo

Returns:

color

info

public String info()

Description copied from class: ExprInfo

Returns a string description of the expression. Contrary to the ExprInfo.toString() method, arguments are not included in the output.

Overrides:

info in class ExprInfo

Returns:

result of check

toString

public String toString()

Specified by:

toString in class ExprInfo