// Copyright 2004, 2005 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.apache.tapestry.contrib.table.model.sql;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Iterator;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * @author mindbridge
 */
public class ResultSetIterator implements Iterator
{

    private static final Log LOG = LogFactory.getLog(ResultSetIterator.class);

    private ResultSet m_objResultSet;
    private boolean m_bFetched;
    private boolean m_bAvailable;

    public ResultSetIterator(ResultSet objResultSet)
    {
        m_objResultSet = objResultSet;
        m_bFetched = false;
    }

    /**
     * @see java.util.Iterator#hasNext()
     */
    public synchronized boolean hasNext()
    {
        if (getResultSet() == null) return false;

        if (!m_bFetched)
        {
            m_bFetched = true;

            try
            {
                m_bAvailable = !getResultSet().isLast();
            }
            catch (SQLException e)
            {
                LOG.warn("SQLException while testing for end of the ResultSet",
                        e);
                m_bAvailable = false;
            }

            if (!m_bAvailable) notifyEnd();
        }

        return m_bAvailable;
    }

    /**
     * @see java.util.Iterator#next()
     */
    public synchronized Object next()
    {
        ResultSet objResultSet = getResultSet();

        try
        {
            if (!objResultSet.next()) return null;
        }
        catch (SQLException e)
        {
            LOG.warn("SQLException while iterating over the ResultSet", e);
            return null;
        }

        m_bFetched = false;
        return objResultSet;
    }

    /**
     * @see java.util.Iterator#remove()
     */
    public void remove()
    {
        try
        {
            getResultSet().deleteRow();
        }
        catch (SQLException e)
        {
            LOG.error("Cannot delete record", e);
        }
    }

    /**
     * Returns the resultSet.
     * 
     * @return ResultSet
     */
    public ResultSet getResultSet()
    {
        return m_objResultSet;
    }

    protected void notifyEnd()
    {
    }

}