empire-db-struts2/src/main/java/org/apache/empire/struts2/actionsupport/ReaderListActionSupport.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.empire.struts2.actionsupport;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.empire.db.DBCommandExpr;
import org.apache.empire.db.DBReader;


/**
 * ReaderListActionSupport
 * <p>
 * This class provides functions for handling list output from a database query through a DBReader object.
 * </p> 
 * @author Rainer
 */
public class ReaderListActionSupport extends ListActionSupport
{
    @SuppressWarnings("hiding")
    protected static Logger log = LoggerFactory.getLogger(RecordActionSupport.class);
    
    protected DBReader  reader;

    public ReaderListActionSupport(ActionBase action, String propertyName)
    {
        super(action, propertyName);
    }
    
    public DBReader getReader()
    {
        return reader;
    }
    
    public void initReader(DBCommandExpr cmd, boolean scrollable)
    {
        // Make sure previous reader is closed
        if (reader!=null)
            reader.close();
        // Create a new reader
        reader = new DBReader();
        reader.open(cmd, scrollable, action.getConnection() );
        // Move to desired Position
        int first = this.getFirstItemIndex();
        if (first>0 && !reader.skipRows(first))
        {   // Page is not valid. Try again from beginning
            reader.close();
            setFirstItem(0);
            initReader(cmd);
        }
    }
    
    public void initReader(DBCommandExpr cmd)
    {
        initReader(cmd, false);
    }

}