org.apache.commons.dbutils.handlers

Class BeanMapHandler<K,V>

java.lang.Object

org.apache.commons.dbutils.handlers.AbstractKeyedHandler<K,V>

org.apache.commons.dbutils.handlers.BeanMapHandler<K,V>

Type Parameters:

K - the type of keys maintained by the returned map

V - the type of the bean

All Implemented Interfaces:

ResultSetHandler<Map<K,V>>

public class BeanMapHandler<K,V>
extends AbstractKeyedHandler<K,V>

ResultSetHandler implementation that returns a Map of Beans. ResultSet rows are converted into Beans which are then stored in a Map under the given key.

If you had a Person table with a primary key column called ID, you could retrieve rows from the table like this:

 ResultSetHandler<Map<Long, Person>> h = new BeanMapHandler<Long, Person>(Person.class, "id");
 Map<Long, Person> found = queryRunner.query("select id, name, age from person", h);
 Person jane = found.get(1L); // jane's id is 1
 String janesName = jane.getName();
 Integer janesAge = jane.getAge();
 

Note that the "id" passed to BeanMapHandler can be in any case. The data type returned for id is dependent upon how your JDBC driver converts SQL column types from the Person table into Java types. The "name" and "age" columns are converted according to their property descriptors by DbUtils. </p>

This class is thread safe. </p>

Since:

1.5

See Also:

ResultSetHandler

Constructor Summary

Constructors

Constructor and Description
BeanMapHandler(Class<V> type) Creates a new instance of BeanMapHandler.
BeanMapHandler(Class<V> type, int columnIndex) Creates a new instance of BeanMapHandler.
BeanMapHandler(Class<V> type, RowProcessor convert) Creates a new instance of BeanMapHandler.
BeanMapHandler(Class<V> type, String columnName) Creates a new instance of BeanMapHandler.

Method Summary

Modifier and Type	Method and Description
protected K	createKey(ResultSet resultSet) This factory method is called by handle() to retrieve the key value from the current ResultSet row.
protected V	createRow(ResultSet resultSet) This factory method is called by handle() to store the current ResultSet row in some object.

Methods inherited from class org.apache.commons.dbutils.handlers.AbstractKeyedHandler

createMap, handle

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BeanMapHandler

public BeanMapHandler(Class<V> type)

Creates a new instance of BeanMapHandler. The value of the first column of each row will be a key in the Map.

Parameters:

type - The Class that objects returned from createRow() are created from.

BeanMapHandler

public BeanMapHandler(Class<V> type,
                      int columnIndex)

Creates a new instance of BeanMapHandler.

Parameters:

type - The Class that objects returned from createRow() are created from.

columnIndex - The values to use as keys in the Map are retrieved from the column at this index.

BeanMapHandler

public BeanMapHandler(Class<V> type,
                      RowProcessor convert)

Creates a new instance of BeanMapHandler. The value of the first column of each row will be a key in the Map.

Parameters:

type - The Class that objects returned from createRow() are created from.

convert - The RowProcessor implementation to use when converting rows into Beans

BeanMapHandler

public BeanMapHandler(Class<V> type,
                      String columnName)

Creates a new instance of BeanMapHandler.

Parameters:

type - The Class that objects returned from createRow() are created from.

columnName - The values to use as keys in the Map are retrieved from the column with this name.

Method Detail

createKey

protected K createKey(ResultSet resultSet)
               throws SQLException

This factory method is called by handle() to retrieve the key value from the current ResultSet row.

Specified by:

createKey in class AbstractKeyedHandler<K,V>

Parameters:

resultSet - ResultSet to create a key from

Returns:

K from the configured key column name/index

Throws:

SQLException - if a database access error occurs

ClassCastException - if the class datatype does not match the column type

See Also:

AbstractKeyedHandler.createKey(ResultSet)

createRow

protected V createRow(ResultSet resultSet)
               throws SQLException

Description copied from class: AbstractKeyedHandler

This factory method is called by handle() to store the current ResultSet row in some object.

Specified by:

createRow in class AbstractKeyedHandler<K,V>

Parameters:

resultSet - ResultSet to create a row from

Returns:

V object created from the current row

Throws:

SQLException - if a database access error occurs