Class JdbcPkGenerator

    • Constructor Detail

      • JdbcPkGenerator

        public JdbcPkGenerator​(JdbcAdapter adapter)
    • Method Detail

      • createAutoPk

        public void createAutoPk​(DataNode node,
                                 List<DbEntity> dbEntities)
                          throws Exception
        Description copied from interface: PkGenerator
        Generates necessary database objects to provide automatic primary key support.
        Specified by:
        createAutoPk in interface PkGenerator
        Parameters:
        node - node that provides access to a DataSource.
        dbEntities - a list of entities that require primary key auto-generation support
        Throws:
        Exception
      • createAutoPkStatements

        public List<String> createAutoPkStatements​(List<DbEntity> dbEntities)
        Description copied from interface: PkGenerator
        Returns a list of SQL strings needed to generates database objects to provide automatic primary support for the list of entities. No actual database operations are performed.
        Specified by:
        createAutoPkStatements in interface PkGenerator
      • dropAutoPk

        public void dropAutoPk​(DataNode node,
                               List<DbEntity> dbEntities)
                        throws Exception
        Drops table named "AUTO_PK_SUPPORT" if it exists in the database.
        Specified by:
        dropAutoPk in interface PkGenerator
        Parameters:
        node - node that provides access to a DataSource.
        dbEntities - a list of entities whose primary key auto-generation support should be dropped.
        Throws:
        Exception
      • dropAutoPkStatements

        public List<String> dropAutoPkStatements​(List<DbEntity> dbEntities)
        Description copied from interface: PkGenerator
        Returns SQL string needed to drop database objects associated with automatic primary key generation. No actual database operations are performed.
        Specified by:
        dropAutoPkStatements in interface PkGenerator
      • pkTableCreateString

        protected String pkTableCreateString()
      • pkCreateString

        protected String pkCreateString​(String entName)
      • pkSelectString

        protected String pkSelectString​(String entName)
      • pkUpdateString

        protected String pkUpdateString​(String entName)
      • dropAutoPkString

        protected String dropAutoPkString()
      • autoPkTableExists

        protected boolean autoPkTableExists​(DataNode node)
                                     throws SQLException
        Checks if AUTO_PK_TABLE already exists in the database.
        Throws:
        SQLException
      • runUpdate

        public int runUpdate​(DataNode node,
                             String sql)
                      throws SQLException
        Runs JDBC update over a Connection obtained from DataNode. Returns a number of objects returned from update.
        Throws:
        SQLException - in case of query failure.
      • generatePk

        public Object generatePk​(DataNode node,
                                 DbAttribute pk)
                          throws Exception
        Generates a unique and non-repeating primary key for specified dbEntity.

        This implementation is naive since it does not lock the database rows when executing select and subsequent update. Adapter-specific implementations are more robust.

        Specified by:
        generatePk in interface PkGenerator
        Throws:
        Exception
        Since:
        3.0
      • longPkFromDatabase

        protected long longPkFromDatabase​(DataNode node,
                                          DbEntity entity)
                                   throws Exception
        Performs primary key generation ignoring cache. Generates a range of primary keys as specified by "pkCacheSize" bean property.

        This method is called internally from "generatePkForDbEntity" and then generated range of key values is saved in cache for performance. Subclasses that implement different primary key generation solutions should override this method, not "generatePkForDbEntity".

        Throws:
        Exception
        Since:
        3.0
      • getPkCacheSize

        public int getPkCacheSize()
        Returns a size of the entity primary key cache. Default value is 20. If cache size is set to a value less or equals than "one", no primary key caching is done.
      • setPkCacheSize

        public void setPkCacheSize​(int pkCacheSize)
        Sets the size of the entity primary key cache. If pkCacheSize parameter is less than 1, cache size is set to "one".

        Note that our tests show that setting primary key cache value to anything much bigger than 20 does not give any significant performance increase. Therefore it does not make sense to use bigger values, since this may potentially create big gaps in the database primary key sequences in cases like application crashes or restarts.

      • reset

        public void reset()
        Description copied from interface: PkGenerator
        Resets any cached primary keys forcing generator to go to the database next time id generation is requested. May not be applicable for all generator implementations.
        Specified by:
        reset in interface PkGenerator