org.basex.query.xpath.expr
Class And

java.lang.Object
  org.basex.query.xpath.expr.Expr
      org.basex.query.xpath.expr.ArrayExpr
          org.basex.query.xpath.expr.And

public final class And
extends ArrayExpr

Logical AND Expression.

Author:

Workgroup DBIS, University of Konstanz 2005-07, ISC License, Tim Petrowsky

Field Summary

Fields inherited from class org.basex.query.xpath.expr.ArrayExpr

exprs

Constructor Summary

And(Expr[] e)
Constructor.

Method Summary

Expr	compile(XPContext ctx) Tries to optimize the Expression.
Bool	eval(XPContext ctx) Evaluates the expression with the specified context set.
Expr	indexEquivalent(XPContext ctx, Step curr) For predicate optimization.
int	indexSizes(XPContext ctx, Step curr, int min) For predicate optimization.

Methods inherited from class org.basex.query.xpath.expr.ArrayExpr

sameAs, toString, usesPos, usesSize

Methods inherited from class org.basex.query.xpath.expr.Expr

returnedValue

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

And

public And(Expr[] e)

Constructor.

Parameters:

e - expressions

Method Detail

compile

public Expr compile(XPContext ctx)
             throws EvalException

Description copied from class: Expr

Tries to optimize the Expression.

Specified by:

compile in class Expr

Parameters:

ctx - expression context

Returns:

optimized Expression

Throws:

EvalException - evaluation exception

eval

public Bool eval(XPContext ctx)
          throws EvalException

Description copied from class: Expr

Evaluates the expression with the specified context set. Additionally provides a context

Specified by:

eval in class Expr

Parameters:

ctx - query context

Returns:

resulting XPathValue

Throws:

EvalException - evaluation exception

indexEquivalent

public Expr indexEquivalent(XPContext ctx,
                            Step curr)
                     throws EvalException

Description copied from class: Expr

For predicate optimization. If possible return an expression yielding the same results using the index. This may not do any changes to the current expression.

Overrides:

indexEquivalent in class Expr

Parameters:

ctx - root

curr - the LocationStep this Expression is a predicate of

Returns:

Equivalent index-expression or null

Throws:

EvalException - evaluation exception

indexSizes

public int indexSizes(XPContext ctx,
                      Step curr,
                      int min)

Description copied from class: Expr

For predicate optimization. If possible return the number of entries an index returns. This may not do any changes to the current expression.

Overrides:

indexSizes in class Expr

Parameters:

ctx - root

curr - the LocationStep this Expression is a predicate of

min - current minimum size

Returns:

Equivalent index-expression or null