/*
* This software is subject to the terms of the Eclipse Public License v1.0
* Agreement, available at the following URL:
* http://www.eclipse.org/legal/epl-v10.html.
* You must accept the terms of that agreement to use this software.
*
* Copyright (c) 2002-2013 Pentaho Corporation.. All rights reserved.
*/
package mondrian.mdx;
import mondrian.calc.*;
import mondrian.calc.impl.AbstractIterCalc;
import mondrian.olap.*;
import mondrian.olap.type.Type;
import java.util.List;
/**
* Usage of a {@link mondrian.olap.NamedSet} in an MDX expression.
*
* @author jhyde
* @since Sep 26, 2005
*/
public class NamedSetExpr extends ExpBase implements Exp {
private final NamedSet namedSet;
/**
* Creates a usage of a named set.
*
* @param namedSet namedSet
* @pre NamedSet != null
*/
public NamedSetExpr(NamedSet namedSet) {
Util.assertPrecondition(namedSet != null, "namedSet != null");
this.namedSet = namedSet;
}
/**
* Returns the named set.
*
* @post return != null
*/
public NamedSet getNamedSet() {
return namedSet;
}
public String toString() {
return namedSet.getUniqueName();
}
public NamedSetExpr clone() {
return new NamedSetExpr(namedSet);
}
public int getCategory() {
return Category.Set;
}
public Exp accept(Validator validator) {
// A set is sometimes used in more than one cube. So, clone the
// expression and re-validate every time it is used.
//
// But keep the expression wrapped in a NamedSet, so that the
// expression is evaluated once per query. (We don't want the
// expression to be evaluated context-sensitive.)
NamedSet namedSet2 = namedSet.validate(validator);
if (namedSet2 == namedSet) {
return this;
}
return new NamedSetExpr(namedSet2);
}
public Calc accept(ExpCompiler compiler) {
// This is a deliberate breach of the usual rules for interpreting
// acceptable result styles. Usually the caller gets to call the shots:
// the callee iterates over the acceptable styles and implements in the
// first style it is able to. But in this case, we return iterable if
// the caller can handle it, even if it isn't the caller's first choice.
// This is because the .current and .currentOrdinal functions only
// work correctly on iterators.
final List<ResultStyle> styleList =
compiler.getAcceptableResultStyles();
if (!styleList.contains(ResultStyle.ITERABLE)
&& !styleList.contains(ResultStyle.ANY))
{
return null;
}
return new AbstractIterCalc(
this,
new Calc[]{/* todo: compile namedSet.getExp() */})
{
public TupleIterable evaluateIterable(
Evaluator evaluator)
{
final Evaluator.NamedSetEvaluator eval = getEval(evaluator);
return eval.evaluateTupleIterable(evaluator);
}
public boolean dependsOn(Hierarchy hierarchy) {
// Given that a named set is never re-evaluated within the
// scope of a query, effectively it's independent of all
// dimensions.
return false;
}
};
}
public Evaluator.NamedSetEvaluator getEval(Evaluator evaluator) {
return evaluator.getNamedSetEvaluator(namedSet, true);
}
public Object accept(MdxVisitor visitor) {
Object o = visitor.visit(this);
if (visitor.shouldVisitChildren()) {
namedSet.getExp().accept(visitor);
}
return o;
}
public Type getType() {
return namedSet.getType();
}
}
// End NamedSetExpr.java