org.basex.query.up
Class Transform

java.lang.Object
  extended by org.basex.query.ExprInfo
      extended by org.basex.query.expr.Expr
          extended by org.basex.query.expr.Arr
              extended by org.basex.query.up.Transform

public final class Transform
extends Arr

Transform expression.

Author:
Workgroup DBIS, University of Konstanz 2005-10, ISC License, Lukas Kircher

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.Arr
expr
 
Constructor Summary
Transform(Let[] c, Expr m, Expr r)
          Constructor.
 
Method Summary
 Item atomic(QueryContext ctx)
          Evaluates the expression and returns the resulting item or a null reference.
 Expr comp(QueryContext ctx)
          Optimizes and compiles the expression.
 void plan(Serializer ser)
          Recursively sends the abstract syntax of this expression to the specified serializer.
 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.Arr
duplicates, indexEquivalent, removable, remove
 
Methods inherited from class org.basex.query.expr.Expr
addText, checkCtx, checkDbl, checkItr, e, ebv, i, indexAccessible, iter, returned, 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

Transform

public Transform(Let[] c,
                 Expr m,
                 Expr r)
Constructor.

Parameters:
c - copy expressions
m - modify expression
r - return expression
Method Detail

comp

public Expr comp(QueryContext ctx)
          throws QueryException
Description copied from class: Expr
Optimizes and compiles the expression.

Overrides:
comp in class Arr
Parameters:
ctx - query context
Returns:
optimized Expression
Throws:
QueryException - query exception

atomic

public Item atomic(QueryContext ctx)
            throws QueryException
Description copied from class: Expr
Evaluates the expression and returns the resulting item or a null reference. If this method is not overwritten, Expr.iter(org.basex.query.QueryContext) must be implemented.

Overrides:
atomic in class Expr
Parameters:
ctx - query context
Returns:
iterator
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 Arr
Parameters:
u - use type to be checked
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 Arr
Parameters:
ser - serializer
Throws:
IOException - I/O exception

toString

public String toString()
Specified by:
toString in class ExprInfo