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
015package org.apache.tapestry.contrib.table.model.sql;
016
017import java.sql.ResultSet;
018import java.sql.SQLException;
019import java.util.Iterator;
020
021import org.apache.commons.logging.Log;
022import org.apache.commons.logging.LogFactory;
023
024/**
025 * 
026 * @author mindbridge
027 */
028public 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}