org.basex.query.expr
Class Or

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.Or

public final class Or
extends Arr

Or 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
Or(Expr[] e)
          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.
 boolean indexAccessible(IndexContext ic)
          Checks if an index can be used for query evaluation.
 Expr indexEquivalent(IndexContext ic)
          Returns an equivalent expression which accesses an index structure.
 Return returned(QueryContext ctx)
          Indicates the return type of an expression.
 String toString()
           
 
Methods inherited from class org.basex.query.expr.Arr
duplicates, plan, removable, remove, uses
 
Methods inherited from class org.basex.query.expr.Expr
addText, checkCtx, checkDbl, checkItr, e, ebv, i, iter, 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

Or

public Or(Expr[] e)
Constructor.

Parameters:
e - expression list
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

indexAccessible

public boolean indexAccessible(IndexContext ic)
                        throws QueryException
Description copied from class: Expr
Checks if an index can be used for query evaluation.

Overrides:
indexAccessible in class Expr
Parameters:
ic - index context
Returns:
true if an index can be used
Throws:
QueryException - query exception

indexEquivalent

public Expr indexEquivalent(IndexContext ic)
                     throws QueryException
Description copied from class: Expr
Returns an equivalent expression which accesses an index structure. Must be called if Expr.indexAccessible(org.basex.query.IndexContext) is implemented for an expression.

Overrides:
indexEquivalent in class Arr
Parameters:
ic - index context
Returns:
Equivalent index-expression or null
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