org.basex.query.expr

Class Union

java.lang.Object

org.basex.data.ExprInfo

org.basex.query.expr.Expr

org.basex.query.expr.ParseExpr

org.basex.query.expr.Arr

org.basex.query.expr.Union

public final class Union
extends Arr

Union expression.

Author:

BaseX Team 2005-12, BSD 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

Fields inherited from class org.basex.query.expr.ParseExpr

input, size, type

Constructor Summary

Constructors

Constructor and Description
Union(InputInfo ii, Expr... e) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
Expr	comp(QueryContext ctx) Compiles and optimizes the expression, assigns data types and cardinalities.
protected NodeCache	eval(Iter[] iter) Evaluates the specified iterators.
protected NodeIter	iter(Iter[] iter) Evaluates the specified iterators in an iterative manner.
NodeIter	iter(QueryContext ctx) Evaluates the expression and returns an iterator on the resulting items.
boolean	iterable() Returns true if the expression is iterable, i.e., if it does not contain any duplicates and if all results are sorted.
java.lang.String	toString()

Methods inherited from class org.basex.query.expr.Arr

allAreValues, count, indexEquivalent, plan, removable, remove, toString, uses

Methods inherited from class org.basex.query.expr.ParseExpr

checkBln, checkColl, checkCreate, checkCtx, checkDbl, checkDBNode, checkEStr, checkEStr, checkIO, checkItem, checkItr, checkItr, checkMap, checkNode, checkNoEmpty, checkStr, checkType, checkUp, checkUp, checkWrite, compBln, ebv, item, optPre, preEval, size, test, type, value

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

addText, compEbv, hasFreeVars, indexAccessible, isEmpty, isFunction, isItem, isVacuous, isValue, markTailCalls, sameAs

Methods inherited from class org.basex.data.ExprInfo

description, info

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Union

public Union(InputInfo ii,
     Expr... e)

Constructor.

Parameters:

ii - input info

e - expression list

Method Detail

comp

public Expr comp(QueryContext ctx)
          throws QueryException

Description copied from class: Expr

Compiles and optimizes the expression, assigns data types and cardinalities.

Parameters:

ctx - query context

Returns:

optimized expression

Throws:

QueryException - query exception

eval

protected NodeCache eval(Iter[] iter)
                  throws QueryException

Evaluates the specified iterators.

Parameters:

iter - iterators

Returns:

resulting iterator

Throws:

QueryException - query exception

iter

protected NodeIter iter(Iter[] iter)

Evaluates the specified iterators in an iterative manner.

Parameters:

iter - iterators

Returns:

resulting iterator

iter

public final NodeIter 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.item(org.basex.query.QueryContext, org.basex.util.InputInfo) must be implemented by an expression, as it may be called by this method.

Overrides:

iter in class ParseExpr

Parameters:

ctx - query context

Returns:

resulting item

Throws:

QueryException - query exception

iterable

public boolean iterable()

Description copied from class: Expr

Returns true if the expression is iterable, i.e., if it does not contain any duplicates and if all results are sorted. This method is called e.g. by AxisPath.

Overrides:

iterable in class Expr

Returns:

result of check

toString

public final java.lang.String toString()

Specified by:

toString in class ExprInfo