3.4.3. The Persistence Interface

The Persistence interface is designed to be an entry point to the data storage functionality provided by the ORM layer.

The interface has the following methods:

  • createTransaction(), getTransaction() – obtain the interface for managing transactions. The methods can accept a data store name. If it is not provided, the main data store is assumed.

  • callInTransaction(), runInTransaction() - execute an action in a new transaction with or without return value. The methods can accept a data store name. If it is not provided, the main data store is assumed.

  • isInTransaction() – checks if there is an active transaction the moment.

  • getEntityManager() – returns an EntityManager instance bound to the current transaction. The method can accept a data store name. If it is not provided, the main data store is assumed.

  • isSoftDeletion() – allows you to determine if the soft deletion mode is active.

  • setSoftDeletion() – enables or disables the soft deletion mode. Setting this property affects all newly created EntityManager instances. Soft deletion is enabled by default.

  • getDbTypeConverter() – returns the DbTypeConverter instance for the main database or for an additional data store.

  • getDataSource() – returns the javax.sql.DataSource instance for the main database or for an additional data store.

    For all javax.sql.Connection objects obtained through getDataSource().getConnection() method the close() method should be called in the finally section after using the connection. Otherwise, the connection will not be returned to the pool. Over time, the pool will overflow and the application will not be able to execute database queries.

  • getTools() – returns an instance of the PersistenceTools interface (see below).