org.basex.query.expr
Class CFrag

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.expr.CFrag
Direct Known Subclasses:
CAttr, CComm, CDoc, CElem, CPI, CText

public abstract class CFrag
extends Arr

Fragment constructor.

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.Arr
expr
 
Constructor Summary
CFrag(Expr... n)
          Constructor.
 
Method Summary
abstract  Nod atomic(QueryContext ctx)
          Evaluates the expression and returns the resulting item or a null reference.
 Return returned(QueryContext ctx)
          Indicates the return type of an expression.
 boolean uses(Expr.Use u, QueryContext ctx)
          Indicates if an expression uses the specified type.
 
Methods inherited from class org.basex.query.expr.Arr
comp, duplicates, indexEquivalent, plan, removable, remove
 
Methods inherited from class org.basex.query.expr.Expr
addText, checkCtx, checkDbl, checkItr, e, ebv, i, indexAccessible, iter, sameAs, size, test, v
 
Methods inherited from class org.basex.query.ExprInfo
color, info, name, toString
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

CFrag

public CFrag(Expr... n)
Constructor.

Parameters:
n - name
Method Detail

atomic

public abstract Nod 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 final 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

returned

public final 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