org.basex.query.xpath.expr
Class Union

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

public final class Union
extends ArrayExpr

XPath Union Expression. This expresses the union of two node sets.

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

Union(Expr[] e)
Constructor.

Method Summary

Expr	compile(XPContext ctx) Tries to optimize the Expression.
NodeSet	eval(XPContext ctx) Evaluates the expression with the specified context set.

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

sameAs, toString, usesPos, usesSize

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

indexEquivalent, indexSizes, returnedValue

Methods inherited from class java.lang.Object

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

Constructor Detail

Union

public Union(Expr[] e)

Constructor.

Parameters:

e - operands joined with the union operator

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 NodeSet 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