001    /**
002     * =========================================
003     * LibFormula : a free Java formula library
004     * =========================================
005     *
006     * Project Info:  http://reporting.pentaho.org/libformula/
007     *
008     * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
009     *
010     * This library is free software; you can redistribute it and/or modify it under the terms
011     * of the GNU Lesser General Public License as published by the Free Software Foundation;
012     * either version 2.1 of the License, or (at your option) any later version.
013     *
014     * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
015     * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
016     * See the GNU Lesser General Public License for more details.
017     *
018     * You should have received a copy of the GNU Lesser General Public License along with this
019     * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
020     * Boston, MA 02111-1307, USA.
021     *
022     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
023     * in the United States and other countries.]
024     *
025     *
026     * ------------
027     * $Id: PowerOperator.java 2752 2007-04-10 14:10:41Z taqua $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    package org.jfree.formula.operators;
032    
033    import org.jfree.formula.EvaluationException;
034    
035    /**
036     * This has to be implemented manually if we want to support arbitary precision.
037     * Damn, do I have to implement the logarithm computation as well? For now:
038     * Ignore that and use doubles!
039     *
040     * @author Thomas Morgner
041     */
042    public class PowerOperator extends AbstractNumericOperator
043    {
044      public PowerOperator()
045      {
046      }
047    
048      protected Number evaluate(final Number number1, final Number number2) throws EvaluationException
049      {
050        final double result = Math.pow(number1.doubleValue(), number2.doubleValue());
051        return new Double(result);
052      }
053    
054      public int getLevel()
055      {
056        return 0;
057      }
058    
059      public String toString()
060      {
061        return "POW";
062      }
063    
064      public boolean isLeftOperation()
065      {
066        return false;
067      }
068    
069      /**
070       * Defines, whether the operation is associative. For associative operations,
071       * the evaluation order does not matter, if the operation appears more than
072       * once in an expression, and therefore we can optimize them a lot better than
073       * non-associative operations (ie. merge constant parts and precompute them
074       * once).
075       *
076       * @return true, if the operation is associative, false otherwise
077       */
078      public boolean isAssociative()
079      {
080        return false;
081      }
082    
083    }