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,v 1.6 2007/04/01 18:49:25 taqua Exp $
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 String column = columns[i];
069 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 GroupByExpression co = (GroupByExpression) super.clone();
126 co.fields = (ArrayList) fields.clone();
127 co.fieldsCached = fieldsCached;
128 return co;
129 }
130 }