org.basex.query.expr
Class CFrag

java.lang.Object
  org.basex.query.ExprInfo
      org.basex.query.expr.Expr
          org.basex.query.expr.Arr
              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