Package mondrian.spi

Interface DialectFactory

All Known Implementing Classes:
JdbcDialectFactory
public interface DialectFactory
Factory that creates Dialect objects.

If you create a class that implements Dialect, you may optionally provide a factory by creating a constant field in that class. For example:

 public class MyDialect implements Dialect {
     public static final DialectFactory FACTORY =
         new JdbcDialectFactory(MyDialect.class, null);

     public MyDialect(Connection connection) {
         ...
     }

     ...
 }

(The field must be public, static, final, named "FACTORY", of type DialectFactory or a subclass, and its value must not be null.)

Explicitly providing a factory gives you more control about how dialects are produced.

If you do not provide such a field, Mondrian requires that the dialect has a public constructor that takes a Connection as a parameter, and automatically creates a factory that calls the class's public constructor.

However, an explicit DialectFactory is superior:

  1. When a dialect cannot handle a given connection, a dialect factory can return null, whereas a dialect's constructor can only throw an exception.
  2. A dialect factory can maintain a pool or cache of dialect objects.

If your dialect is a subclass of JdbcDialectImpl you may wish to use a dialect factory that is a subclass of JdbcDialectFactory.

Since:
Jan 13, 2009
Author:
jhyde

  • Method Details

    • createDialect

      Dialect createDialect(DataSource dataSource, Connection connection)
      Creates a Dialect.

      If the dialect cannot handle this connection, returns null.

      Parameters:
      dataSource - JDBC data source
      connection - JDBC connection
      Returns:
      dialect for this connection, or null if this factory's dialect is not appropriate for the connection
      Throws:
      RuntimeException - if underlying systems give an error