org.basex.query.expr
Class Root

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

public final class Root
extends Simple

Root node.

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
 
Constructor Summary
Root()
           
 
Method Summary
 Iter iter(QueryContext ctx)
          Evaluates the expression and returns an iterator on the resulting items.
 Return returned(QueryContext ctx)
          Indicates the return type of an expression.
 Nod root(Item i)
          Returns the root node of the specified item.
 boolean sameAs(Expr cmp)
          Checks the current and specified expression for equality.
 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.Simple
color, comp, plan
 
Methods inherited from class org.basex.query.expr.Expr
addText, atomic, checkCtx, checkDbl, checkItr, duplicates, e, ebv, i, indexAccessible, indexEquivalent, removable, remove, size, test, v
 
Methods inherited from class org.basex.query.ExprInfo
info, name
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

Root

public Root()
Method Detail

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

root

public Nod root(Item i)
Returns the root node of the specified item.

Parameters:
i - input node
Returns:
root node

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 Simple
Parameters:
u - use type to be checked
ctx - query context
Returns:
result of check

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

sameAs

public boolean sameAs(Expr cmp)
Description copied from class: Expr
Checks the current and specified expression for equality.

Overrides:
sameAs in class Expr
Parameters:
cmp - expression to be compared
Returns:
result of check

toString

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