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     * @author mindbridge
026     */
027    public class ResultSetIterator implements Iterator
028    {
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("SQLException while testing for end of the ResultSet",
060                            e);
061                    m_bAvailable = false;
062                }
063    
064                if (!m_bAvailable) notifyEnd();
065            }
066    
067            return m_bAvailable;
068        }
069    
070        /**
071         * @see java.util.Iterator#next()
072         */
073        public synchronized Object next()
074        {
075            ResultSet objResultSet = getResultSet();
076    
077            try
078            {
079                if (!objResultSet.next()) return null;
080            }
081            catch (SQLException e)
082            {
083                LOG.warn("SQLException while iterating over the ResultSet", e);
084                return null;
085            }
086    
087            m_bFetched = false;
088            return objResultSet;
089        }
090    
091        /**
092         * @see java.util.Iterator#remove()
093         */
094        public void remove()
095        {
096            try
097            {
098                getResultSet().deleteRow();
099            }
100            catch (SQLException e)
101            {
102                LOG.error("Cannot delete record", e);
103            }
104        }
105    
106        /**
107         * Returns the resultSet.
108         * 
109         * @return ResultSet
110         */
111        public ResultSet getResultSet()
112        {
113            return m_objResultSet;
114        }
115    
116        protected void notifyEnd()
117        {
118        }
119    
120    }