001/* 002// This software is subject to the terms of the Eclipse Public License v1.0 003// Agreement, available at the following URL: 004// http://www.eclipse.org/legal/epl-v10.html. 005// You must accept the terms of that agreement to use this software. 006// 007// Copyright (C) 2006-2011 Pentaho 008// All Rights Reserved. 009*/ 010package mondrian.olap.fun; 011 012import mondrian.calc.*; 013import mondrian.calc.impl.AbstractDoubleCalc; 014import mondrian.calc.impl.ValueCalc; 015import mondrian.mdx.ResolvedFunCall; 016import mondrian.olap.*; 017 018/** 019 * Definition of the <code>Var</code> MDX builtin function 020 * (and its synonym <code>Variance</code>). 021 * 022 * @author jhyde 023 * @since Mar 23, 2006 024 */ 025class VarFunDef extends AbstractAggregateFunDef { 026 static final Resolver VarResolver = 027 new ReflectiveMultiResolver( 028 "Var", 029 "Var(<Set>[, <Numeric Expression>])", 030 "Returns the variance of a numeric expression evaluated over a set (unbiased).", 031 new String[]{"fnx", "fnxn"}, 032 VarFunDef.class); 033 034 static final Resolver VarianceResolver = 035 new ReflectiveMultiResolver( 036 "Variance", 037 "Variance(<Set>[, <Numeric Expression>])", 038 "Alias for Var.", 039 new String[]{"fnx", "fnxn"}, 040 VarFunDef.class); 041 042 public VarFunDef(FunDef dummyFunDef) { 043 super(dummyFunDef); 044 } 045 046 public Calc compileCall(ResolvedFunCall call, ExpCompiler compiler) { 047 final ListCalc listCalc = 048 compiler.compileList(call.getArg(0)); 049 final Calc calc = 050 call.getArgCount() > 1 051 ? compiler.compileScalar(call.getArg(1), true) 052 : new ValueCalc(call); 053 return new AbstractDoubleCalc(call, new Calc[] {listCalc, calc}) { 054 public double evaluateDouble(Evaluator evaluator) { 055 final int savepoint = evaluator.savepoint(); 056 try { 057 evaluator.setNonEmpty(false); 058 TupleList list = evaluateCurrentList(listCalc, evaluator); 059 final double var = 060 (Double) var( 061 evaluator, list, calc, false); 062 return var; 063 } finally { 064 evaluator.restore(savepoint); 065 } 066 } 067 068 public boolean dependsOn(Hierarchy hierarchy) { 069 return anyDependsButFirst(getCalcs(), hierarchy); 070 } 071 }; 072 } 073} 074 075// End VarFunDef.java