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: PrefixTerm.java 2780 2007-05-07 22:51:12Z mimil $
028     * ------------
029     * (C) Copyright 2006-2007, by Pentaho Corporation.
030     */
031    package org.jfree.formula.lvalues;
032    
033    import org.jfree.formula.operators.PrefixOperator;
034    import org.jfree.formula.EvaluationException;
035    
036    /**
037     * Creation-Date: 02.11.2006, 10:20:27
038     *
039     * @author Thomas Morgner
040     */
041    public class PrefixTerm extends AbstractLValue
042    {
043      private PrefixOperator operator;
044      private LValue value;
045    
046      public PrefixTerm(final PrefixOperator operator, final LValue value)
047      {
048        if (operator == null)
049        {
050          throw new NullPointerException();
051        }
052        if (value == null)
053        {
054          throw new NullPointerException();
055        }
056    
057        this.operator = operator;
058        this.value = value;
059      }
060    
061      public PrefixOperator getOperator()
062      {
063        return operator;
064      }
065    
066      public LValue getValue()
067      {
068        return value;
069      }
070    
071    
072      public TypeValuePair evaluate() throws EvaluationException
073      {
074        return operator.evaluate(getContext(), value.evaluate());
075      }
076    
077    
078      public String toString()
079      {
080        return "(" + operator + value + ")";
081      }
082    
083      /**
084       * Returns any dependent lvalues (parameters and operands, mostly).
085       *
086       * @return
087       */
088      public LValue[] getChildValues()
089      {
090        return new LValue[]{ value };
091      }
092    
093      /**
094       * Checks, whether the LValue is constant. Constant lvalues always return the
095       * same value.
096       *
097       * @return
098       */
099      public boolean isConstant()
100      {
101        return value.isConstant();
102      }
103    
104      public Object clone() throws CloneNotSupportedException
105      {
106        final PrefixTerm o = (PrefixTerm) super.clone();
107        o.value = (LValue) value.clone();
108        return o;
109      }
110    }