lutece-dao

DAO & Home Patterns — Lutece 8

Before writing DAO or Home code, consult ~/.lutece-references/lutece-core/ and ~/.lutece-references/lutece-form-plugin-forms/ using Read, Grep and Glob.

DAO Class Structure

@ApplicationScoped
@Named( "myplugin.entityDAO" )
public class EntityDAO implements IEntityDAO
{
    private static final String SQL_QUERY_NEWPK = "SELECT max( id_entity ) FROM myplugin_entity";
    private static final String SQL_QUERY_SELECT = "SELECT id_entity, title, description FROM myplugin_entity WHERE id_entity = ?";
    private static final String SQL_QUERY_INSERT = "INSERT INTO myplugin_entity ( id_entity, title, description ) VALUES ( ?, ?, ? )";
    private static final String SQL_QUERY_UPDATE = "UPDATE myplugin_entity SET title = ?, description = ? WHERE id_entity = ?";
    private static final String SQL_QUERY_DELETE = "DELETE FROM myplugin_entity WHERE id_entity = ?";
    private static final String SQL_QUERY_SELECTALL = "SELECT id_entity, title, description FROM myplugin_entity";
    // ...
}

SQL Constant Naming

Constant	Usage
SQL_QUERY_NEWPK	SELECT max(id_xxx) FROM table
SQL_QUERY_SELECT	Single row by PK
SQL_QUERY_INSERT	Insert row
SQL_QUERY_UPDATE	Update row by PK
SQL_QUERY_DELETE	Delete row by PK
SQL_QUERY_SELECTALL	All rows
SQL_QUERY_SELECT_BY_*	Custom finders
SQL_QUERY_COUNT_*	Count queries

DAOUtil Lifecycle

Always use try-with-resources (auto-closes):

INSERT / UPDATE / DELETE

public void insert( Entity entity, Plugin plugin )
{
    try ( DAOUtil daoUtil = new DAOUtil( SQL_QUERY_INSERT, plugin ) )
    {
        int nIndex = 1;
        daoUtil.setInt( nIndex++, entity.getId( ) );
        daoUtil.setString( nIndex++, entity.getTitle( ) );
        daoUtil.setString( nIndex++, entity.getDescription( ) );
        daoUtil.executeUpdate( );
    }
}

SELECT (single row)

public Entity load( int nKey, Plugin plugin )
{
    Entity entity = null;
    try ( DAOUtil daoUtil = new DAOUtil( SQL_QUERY_SELECT, plugin ) )
    {
        daoUtil.setInt( 1, nKey );
        daoUtil.executeQuery( );

        if ( daoUtil.next( ) )
        {
            int nIndex = 1;
            entity = new Entity( );
            entity.setId( daoUtil.getInt( nIndex++ ) );
            entity.setTitle( daoUtil.getString( nIndex++ ) );
            entity.setDescription( daoUtil.getString( nIndex++ ) );
        }
    }
    return entity;
}

SELECT (collection)

public List<Entity> selectAll( Plugin plugin )
{
    List<Entity> listEntities = new ArrayList<>( );
    try ( DAOUtil daoUtil = new DAOUtil( SQL_QUERY_SELECTALL, plugin ) )
    {
        daoUtil.executeQuery( );

        while ( daoUtil.next( ) )
        {
            int nIndex = 1;
            Entity entity = new Entity( );
            entity.setId( daoUtil.getInt( nIndex++ ) );
            entity.setTitle( daoUtil.getString( nIndex++ ) );
            entity.setDescription( daoUtil.getString( nIndex++ ) );
            listEntities.add( entity );
        }
    }
    return listEntities;
}

DAOUtil Parameter Types

Parameters and results are 1-indexed. Use nIndex++ for sequential access.

Type	Setter	Getter
int	setInt( n, val )	getInt( n )
String	setString( n, val )	getString( n )
long	setLong( n, val )	getLong( n )
boolean	setBoolean( n, val )	getBoolean( n )
double	setDouble( n, val )	getDouble( n )
Timestamp	setTimestamp( n, val )	getTimestamp( n )
Date	setDate( n, val )	getDate( n )

Interface Pattern

Every DAO has an interface:

public interface IEntityDAO
{
    void insert( Entity entity, Plugin plugin );
    Entity load( int nKey, Plugin plugin );
    void store( Entity entity, Plugin plugin );
    void delete( int nKey, Plugin plugin );
    List<Entity> selectAll( Plugin plugin );
    ReferenceList selectReferenceList( Plugin plugin );
}

Home — Static Facade

public final class EntityHome
{
    private static IEntityDAO _dao = CDI.current( ).select( IEntityDAO.class ).get( );
    private static Plugin _plugin = PluginService.getPlugin( "myplugin" );

    private EntityHome( ) { }

    public static Entity create( Entity entity )
    {
        _dao.insert( entity, _plugin );
        return entity;
    }

    public static Entity update( Entity entity )
    {
        _dao.store( entity, _plugin );
        return entity;
    }

    public static void remove( int nKey )
    {
        _dao.delete( nKey, _plugin );
    }

    public static Entity findByPrimaryKey( int nKey )
    {
        return _dao.load( nKey, _plugin );
    }

    public static List<Entity> findAll( )
    {
        return _dao.selectAll( _plugin );
    }

    public static ReferenceList findReferenceList( )
    {
        return _dao.selectReferenceList( _plugin );
    }
}

Collection Types

Return type	When
List<Entity>	Standard list of entities
ReferenceList	Key-value pairs for dropdowns (<select>)
Optional<Entity>	Optional single result (modern style)

Reference Sources

Need	File to consult
Core DAO patterns	~/.lutece-references/lutece-core/src/java/**/business/
Core Home patterns	~/.lutece-references/lutece-core/src/java/**/business/
DAOUtil source	~/.lutece-references/lutece-core/src/java/**/util/sql/DAOUtil.java
Forms plugin DAO examples	~/.lutece-references/lutece-form-plugin-forms/src/java/**/business/