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) 2006-2007 Pentaho 008// All Rights Reserved. 009*/ 010package mondrian.calc; 011 012import mondrian.olap.Evaluator; 013import mondrian.olap.Level; 014 015/** 016 * Expression which yields a {@link mondrian.olap.Level}. 017 * 018 * <p>When implementing this interface, it is convenient to extend 019 * {@link mondrian.calc.impl.AbstractLevelCalc}, but it is not required. 020 * 021 * @author jhyde 022 * @since Sep 26, 2005 023 */ 024public interface LevelCalc extends Calc { 025 /** 026 * Evaluates this expression to yield a level. 027 * 028 * <p>Never returns null. 029 * 030 * @param evaluator Evaluation context 031 * @return a level 032 */ 033 Level evaluateLevel(Evaluator evaluator); 034} 035 036// End LevelCalc.java