org.basex.query.expr
Class Case

java.lang.Object
  extended by org.basex.query.ExprInfo
      extended by org.basex.query.expr.Expr
          extended by org.basex.query.expr.Single
              extended by 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