package liquibase.sqlgenerator.core;

 import liquibase.database.Database;

 import liquibase.database.core.PostgresDatabase;

 import liquibase.exception.DatabaseException;

 import liquibase.exception.UnexpectedLiquibaseException;

 import liquibase.exception.ValidationErrors;

 import liquibase.sql.Sql;

 import liquibase.sql.UnparsedSql;

 import liquibase.sqlgenerator.SqlGenerator;

 import liquibase.sqlgenerator.SqlGeneratorChain;

 import liquibase.statement.core.SelectSequencesStatement;

 public class SelectSequencesGeneratorPostgres extends AbstractSqlGenerator<SelectSequencesStatement> {

     @Override

     public int getPriority() {

         return PRIORITY_DATABASE;

     }

     @Override

     public boolean supports(SelectSequencesStatement statement, Database database) {

         return database instanceof PostgresDatabase;

     }

     public ValidationErrors validate(SelectSequencesStatement statement, Database database,

             SqlGeneratorChain sqlGeneratorChain) {

         return new ValidationErrors();

     }

     public Sql[] generateSql(SelectSequencesStatement statement, Database database, SqlGeneratorChain sqlGeneratorChain) {

         try {

             String schema = statement.getSchemaName();

             return new Sql[] { new UnparsedSql(

                     "SELECT relname AS SEQUENCE_NAME FROM pg_class, pg_namespace "

                             + "WHERE relkind='S' "

                             + "AND pg_class.relnamespace = pg_namespace.oid "

                             + "AND nspname = '"

                             + database.convertRequestedSchemaToSchema(schema)

                             + "' "

                             + "AND 'nextval(''"

                             + (schema == null ? "" : schema + ".")

                             + "'||relname||'''::regclass)' not in (select adsrc from pg_attrdef where adsrc is not null) "

                             + "AND 'nextval(''"

                             + (schema == null ? "" : schema + ".")

                             + "\"'||relname||'\"''::regclass)' not in (select adsrc from pg_attrdef where adsrc is not null) "

                             + "AND 'nextval('''||relname||'''::regclass)' not in (select adsrc from pg_attrdef where adsrc is not null)") };

         } catch (DatabaseException e) {

             throw new UnexpectedLiquibaseException(e);

         }

     }

 }