org.basex.query.expr
Class If

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.If

public final class If
extends Arr

If 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.Arr
expr
 
Constructor Summary
If(Expr e, Expr t, Expr s)
          Constructor.
 
Method Summary
 Expr comp(QueryContext ctx)
          Optimizes and compiles the expression.
 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.
 String toString()
           
 
Methods inherited from class org.basex.query.expr.Arr
duplicates, indexEquivalent, plan, removable, remove, uses
 
Methods inherited from class org.basex.query.expr.Expr
addText, atomic, checkCtx, checkDbl, checkItr, e, ebv, i, indexAccessible, 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

If

public If(Expr e,
          Expr t,
          Expr s)
Constructor.

Parameters:
e - expression
t - then clause
s - else clause
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

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

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

toString

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