001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.contrib.table.model.sql;
016    
017    import java.sql.ResultSet;
018    import java.sql.SQLException;
019    import java.util.Iterator;
020    
021    import org.apache.commons.logging.Log;
022    import org.apache.commons.logging.LogFactory;
023    
024    /**
025     * 
026     * @author mindbridge
027     */
028    public class ResultSetIterator implements Iterator
029    {
030            private static final Log LOG = LogFactory.getLog(ResultSetIterator.class);
031    
032            private ResultSet m_objResultSet;
033            private boolean m_bFetched;
034            private boolean m_bAvailable;
035    
036            public ResultSetIterator(ResultSet objResultSet)
037            {
038                    m_objResultSet = objResultSet;
039                    m_bFetched = false;
040            }
041    
042            /**
043             * @see java.util.Iterator#hasNext()
044             */
045            public synchronized boolean hasNext()
046            {
047            if (getResultSet() == null) return false;
048            
049                    if (!m_bFetched)
050                    {
051                            m_bFetched = true;
052    
053                            try
054                            {
055                                    m_bAvailable = !getResultSet().isLast();
056                            }
057                            catch (SQLException e)
058                            {
059                                    LOG.warn(
060                                            "SQLException while testing for end of the ResultSet",
061                                            e);
062                                    m_bAvailable = false;
063                            }
064    
065                            if (!m_bAvailable)
066                                    notifyEnd();
067                    }
068    
069                    return m_bAvailable;
070            }
071    
072            /**
073             * @see java.util.Iterator#next()
074             */
075            public synchronized Object next()
076            {
077                    ResultSet objResultSet = getResultSet();
078    
079                    try
080                    {
081                            if (!objResultSet.next())
082                                    return null;
083                    }
084                    catch (SQLException e)
085                    {
086                            LOG.warn("SQLException while iterating over the ResultSet", e);
087                            return null;
088                    }
089    
090                    m_bFetched = false;
091                    return objResultSet;
092            }
093    
094            /**
095             * @see java.util.Iterator#remove()
096             */
097            public void remove()
098            {
099                    try
100                    {
101                            getResultSet().deleteRow();
102                    }
103                    catch (SQLException e)
104                    {
105                            LOG.error("Cannot delete record", e);
106                    }
107            }
108    
109            /**
110             * Returns the resultSet.
111             * @return ResultSet
112             */
113            public ResultSet getResultSet()
114            {
115                    return m_objResultSet;
116            }
117    
118            protected void notifyEnd()
119            {
120            }
121    
122    }