Package org.dspace.core

Interface DBConnection<T>

  • Type Parameters:
    T - type of the persistence provider's session object.
    All Known Implementing Classes:
    HibernateDBConnection
    public interface DBConnection<T>
    Interface representing a persistence provider "session". Implementations will wrap something like a JPA EntityManager or a Hibernate Session. The terms "database" and "connection" are historic and have no direct relationship to a JDBC Connection or even a connection pool.

    This class should only be accessed by an enclosing Context object.

    Note that the user's HTTPSession is an unrelated concept.

    Author:
    kevinvandevelde at atmire.com

    • Method Detail

      • getSession

        T getSession()
      throws SQLException
        Access to the underlying persistence provider's session object.
        Returns:
        the provider's session object for this connection.
        Throws:
        SQLException - passed through.

      • isTransActionAlive

        boolean isTransActionAlive()
        Returns:
        true if this session has an uncommitted transaction.

      • isSessionAlive

        boolean isSessionAlive()
        Returns:
        true if the session is open, false if it has been closed.

      • closeDBConnection

        void closeDBConnection()
                throws SQLException
        Close this session: close DBMS connection(s) and clean up resources.
        Throws:
        SQLException - passed through.

      • shutdown

        void shutdown()
        Close all sessions. Release all associated resources (cache, DBMS connections, etc.) To be used only when exiting the application.

      • getType

        String getType()
        Some description of the DBMS used to persist entities.
        Returns:
        Brand, version, dialect, etc. Implementation specific.

      • getDataSource

        DataSource getDataSource()
        The JDBC DataSource used by this session. Think carefully before using.
        Returns:
        the source of DBMS connections.

      • getDatabaseConfig

        DatabaseConfigVO getDatabaseConfig()
                            throws SQLException
        Identify certain characteristics of the DBMS being used to support persistence.
        Returns:
        a collection of DBMS, database and connection information.
        Throws:
        SQLException - passed through.

      • setConnectionMode

        void setConnectionMode​(boolean batchOptimized,
                       boolean readOnlyOptimized)
                throws SQLException
        Configure the connection for special uses.
        Parameters:
        batchOptimized - if true, optimize for batch use. Typically this means suppressing automatic flushing of updates, thus requiring manual flushing at appropriate points in the process.
        readOnlyOptimized - if true, optimize for read-only use. Typically this suppresses all updating.
        Throws:
        SQLException

      • isOptimizedForBatchProcessing

        boolean isOptimizedForBatchProcessing()
        Has this session been configured for large batches? Typically this means that automatic flushing of updates to the database is suppressed, and thus one must take care to flush manually (or commit) at appropriate times.
        Returns:
        true if configured for batch.

      • getCacheSize

        long getCacheSize()
           throws SQLException
        How many entities are cached in this session?
        Returns:
        number of cached entities.
        Throws:
        SQLException - passed through.

      • reloadEntity

        <E extends ReloadableEntity> E reloadEntity​(E entity)
                                     throws SQLException
        Reload a DSpace object from the database. This will make sure the object is valid and stored in the cache. The returned object should be used henceforth instead of the passed object.
        Type Parameters:
        E - type of entity
        Parameters:
        entity - The DSpace object to reload
        Returns:
        the reloaded entity.
        Throws:
        SQLException - passed through.

      • uncacheEntity

        <E extends ReloadableEntity> void uncacheEntity​(E entity)
                                         throws SQLException
        Remove a DSpace object from the session cache when batch processing a large number of objects.

        Objects removed from cache are not saved in any way. Therefore, if you have modified an object, you should be sure to commit() changes before calling this method.

        Type Parameters:
        E - Type of entity
        Parameters:
        entity - The DSpace object to decache.
        Throws:
        SQLException - passed through.

      • flushSession

        void flushSession()
           throws SQLException
        Do a manual flush. This synchronizes the in-memory state of the Session with the database (write changes to the database)
        Throws:
        SQLException - passed through.