com.firefly.db.jdbc.helper.DefaultBeanMapHandler Maven / Gradle / Ivy
package com.firefly.db.jdbc.helper;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.apache.commons.dbutils.RowProcessor;
import org.apache.commons.dbutils.handlers.AbstractKeyedHandler;
public class DefaultBeanMapHandler extends AbstractKeyedHandler {
/**
* The Class of beans produced by this handler.
*/
private final Class type;
/**
* The RowProcessor implementation to use when converting rows into Objects.
*/
private final RowProcessor convert;
/**
* The column index to retrieve key values from. Defaults to 1.
*/
private final int columnIndex;
/**
* The column name to retrieve key values from. Either columnName or
* columnIndex will be used but never both.
*/
private final String columnName;
/**
* Creates a new instance of BeanMapHandler. The value of the first column
* of each row will be a key in the Map.
*
* @param type
* The Class that objects returned from createRow()
* are created from.
* @param convert
* The RowProcessor implementation to use when
* converting rows into Beans
*@param columnName
* The values to use as keys in the Map are retrieved from the
* column with this name.
*/
public DefaultBeanMapHandler(Class type, RowProcessor convert, String columnName) {
this(type, convert, 1, columnName);
}
/**
* Private Helper
*
* @param convert
* The RowProcessor implementation to use when
* converting rows into Beans
* @param columnIndex
* The values to use as keys in the Map are retrieved from the
* column at this index.
* @param columnName
* The values to use as keys in the Map are retrieved from the
* column with this name.
*/
public DefaultBeanMapHandler(Class type, RowProcessor convert,
int columnIndex, String columnName) {
this.type = type;
this.convert = convert;
this.columnIndex = columnIndex;
this.columnName = columnName;
}
/**
* This factory method is called by handle() to retrieve the
* key value from the current ResultSet row.
* @param rs ResultSet to create a key from
*
* @return K from the configured key column name/index
*
* @throws SQLException if a database access error occurs
* @throws ClassCastException if the class datatype does not match the column type
*
* @see org.apache.commons.dbutils.handlers.AbstractKeyedHandler#createKey(ResultSet)
*/
// We assume that the user has picked the correct type to match the column
// so getObject will return the appropriate type and the cast will succeed.
@SuppressWarnings("unchecked")
@Override
protected K createKey(ResultSet rs) throws SQLException {
return (columnName == null) ?
(K) rs.getObject(columnIndex) :
(K) rs.getObject(columnName);
}
@Override
protected V createRow(ResultSet rs) throws SQLException {
return this.convert.toBean(rs, type);
}
}