org.basex.query.expr
Class Case

java.lang.Object
  org.basex.query.ExprInfo
      org.basex.query.expr.Expr
          org.basex.query.expr.Single
              org.basex.query.expr.Case

public final class Case
extends Single

Case 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

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

expr

Constructor Summary

Case(Var v, Expr r)
Constructor.

Method Summary

Case	comp(QueryContext ctx) Optimizes and compiles the expression.
Case	comp(QueryContext ctx, Item it) Compiles the expression.
void	plan(Serializer ser) Recursively sends the abstract syntax of this expression to the specified serializer.
Case	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, iter, removable, sameAs, size, test, v

Methods inherited from class org.basex.query.ExprInfo

color, info, name

Methods inherited from class java.lang.Object

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

Constructor Detail

Case

public Case(Var v,
            Expr r)

Constructor.

Parameters:

v - variable

r - return expression

Method Detail

comp

public Case comp(QueryContext ctx)
          throws QueryException

Description copied from class: Expr

Optimizes and compiles the expression.

Overrides:

comp in class Single

Parameters:

ctx - query context

Returns:

optimized Expression

Throws:

QueryException - query exception

comp

public Case comp(QueryContext ctx,
                 Item it)
          throws QueryException

Compiles the expression.

Parameters:

ctx - query context

it - item to be bound

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".

Overrides:

uses in class Single

Parameters:

u - use type to be checked

ctx - query context

Returns:

result of check

remove

public Case remove(Var v)

Description copied from class: Expr

Removes the specified variable in a sub expression.

Overrides:

remove in class Single

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.

Overrides:

plan in class Single

Parameters:

ser - serializer

Throws:

IOException - I/O exception

toString

public String toString()

Specified by:

toString in class ExprInfo