001    /**
002     * ========================================
003     * JFreeReport : a free Java report library
004     * ========================================
005     *
006     * Project Info:  http://reporting.pentaho.org/
007     *
008     * (C) Copyright 2000-2007, by Object Refinery Limited, 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     * $Id: GroupByExpression.java 3525 2007-10-16 11:43:48Z tmorgner $
027     * ------------
028     * (C) Copyright 2000-2005, by Object Refinery Limited.
029     * (C) Copyright 2005-2007, by Pentaho Corporation.
030     */
031    package org.jfree.report.expressions.sys;
032    
033    import java.util.ArrayList;
034    import java.util.Arrays;
035    
036    import org.jfree.report.DataFlags;
037    import org.jfree.report.DataRow;
038    import org.jfree.report.DataSourceException;
039    import org.jfree.report.expressions.AbstractExpression;
040    
041    /**
042     * Creation-Date: 08.10.2006, 16:28:37
043     *
044     * @author Thomas Morgner
045     */
046    public class GroupByExpression extends AbstractExpression
047    {
048      private ArrayList fields;
049      private transient String[] fieldsCached;
050    
051      public GroupByExpression()
052      {
053        this.fields = new ArrayList();
054      }
055    
056      /**
057       * Return the current expression value. <P> The value depends (obviously) on
058       * the expression implementation.
059       *
060       * @return the value of the function.
061       */
062      public Object computeValue() throws DataSourceException
063      {
064        final DataRow dr = getDataRow();
065        final String[] columns = getField();
066        for (int i = 0; i < columns.length; i++)
067        {
068          final String column = columns[i];
069          final DataFlags df = dr.getFlags(column);
070          if (df == null)
071          {
072            // invalid column or invalid implementation ...
073            continue;
074          }
075          if (df.isChanged())
076          {
077            //Log.debug ("Field: " + df.getName() + " has changed to " + df.getValue());
078            return Boolean.TRUE;
079          }
080        }
081        return Boolean.FALSE;
082      }
083    
084      public void setField (final int index, final String field)
085      {
086        if (fields.size() == index)
087        {
088          fields.add(field);
089        }
090        else
091        {
092          fields.set(index, field);
093        }
094        fieldsCached = null;
095      }
096    
097      public String getField (final int index)
098      {
099        return (String) fields.get(index);
100      }
101    
102      public int getFieldCount ()
103      {
104        return fields.size();
105      }
106    
107      public String[] getField ()
108      {
109        if (fieldsCached == null)
110        {
111          fieldsCached = (String[]) fields.toArray(new String[fields.size()]);
112        }
113        return (String[]) fieldsCached.clone();
114      }
115    
116      public void setField (final String[] fields)
117      {
118        this.fields.clear();
119        this.fields.addAll(Arrays.asList(fields));
120        this.fieldsCached = (String[]) fields.clone();
121      }
122    
123      public Object clone() throws CloneNotSupportedException
124      {
125        final GroupByExpression co = (GroupByExpression) super.clone();
126        co.fields = (ArrayList) fields.clone();
127        co.fieldsCached = fieldsCached;
128        return co;
129      }
130    }