net.orpiske.ssps.common.db.MultiRsHandler.java Source code

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Here is the source code for net.orpiske.ssps.common.db.MultiRsHandler.java

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/**
   Copyright 2012 Otavio Rodolfo Piske
    
   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 net.orpiske.ssps.common.db;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

import net.orpiske.ssps.common.utils.NameConverter;

import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.dbutils.handlers.AbstractListHandler;

/**
 * Handles the result of a query
 * 
 * @author Otavio R. Piske <angusyoung@gmail.com>
 * @param <T> The type of the DTO
 */
public class MultiRsHandler<T> extends AbstractListHandler<T> {

    private Class<T> clazz;

    /**
     * Constructor
     * @param clazz The class of the DTO to handle
     */
    public MultiRsHandler(Class<T> clazz) {
        this.clazz = clazz;
    }

    /* (non-Javadoc)
     * @see org.apache.commons.dbutils.handlers.AbstractListHandler#handleRow(java.sql.ResultSet)
     */
    @Override
    protected T handleRow(ResultSet rs) throws SQLException {
        T dto;

        try {
            dto = clazz.newInstance();
        } catch (InstantiationException e1) {
            throw new SQLException("Unable to instantiate DTO class: " + e1.getMessage(), e1);
        } catch (IllegalAccessException e1) {
            throw new SQLException("Illegal to instantiate DTO class: " + e1.getMessage(), e1);
        }

        ResultSetMetaData meta = rs.getMetaData();

        for (int i = 1; i <= meta.getColumnCount(); i++) {
            Object value = rs.getObject(i);
            String name = meta.getColumnName(i);

            try {
                /*
                 * We convert the column name to a more appropriate and java like name 
                 * because some columns are usually named as some_thing whereas Java 
                 * properties are named someThing. This call does this conversion.
                 */
                String javaProperty = NameConverter.sqlToProperty(name);

                PropertyUtils.setSimpleProperty(dto, javaProperty, value);
            } catch (Exception e) {
                throw new SQLException("Unable to set property " + name + " for bean" + dto.getClass(), e);
            }
        }

        return dto;
    }
}