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  package org.apache.cayenne.dba;
  
  import java.util.List;
  
  import org.apache.cayenne.access.DataNode;
  import org.apache.cayenne.map.DbAttribute;
  import org.apache.cayenne.map.DbEntity;
  
  /**
   * Defines methods to support automatic primary key generation.
   */
  public interface PkGenerator {
  
  
      /**
       * Generates necessary database objects to provide automatic primary key support.
       *
       * @param node       node that provides access to a DataSource.
       * @param dbEntities a list of entities that require primary key auto-generation
       *                   support
       */
      void createAutoPk(DataNode node, List<DbEntity> dbEntities) throws Exception;
  
      /**
       * 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.
       */
      List<String> createAutoPkStatements(List<DbEntity> dbEntities);
  
      /**
       * Drops any common database objects associated with automatic primary key generation
       * process. This may be lookup tables, special stored procedures or sequences.
       *
       * @param node       node that provides access to a DataSource.
       * @param dbEntities a list of entities whose primary key auto-generation support
       *                   should be dropped.
       */
      void dropAutoPk(DataNode node, List<DbEntity> dbEntities) throws Exception;
  
      /**
       * Returns SQL string needed to drop database objects associated with automatic
       * primary key generation. No actual database operations are performed.
       */
      List<String> dropAutoPkStatements(List<DbEntity> dbEntities);
  
      /**
       * Generates a unique and non-repeating primary key for specified PK attribute.
       *
       * @since 3.0
       */
      Object generatePk(DataNode dataNode, DbAttribute pk) throws Exception;
  
      /**
       * Install the adapter associated with current PkGenerator
       *
       * @since 4.1
       */
      void setAdapter(DbAdapter q);
  
      /**
       * Get an adapter associated with current PkGenerator
       *
       * @since 4.1
       */
      DbAdapter getAdapter();
  
      /**
       * 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.
       */
      void reset();
  }
  