package liquibase.sqlgenerator.core;
   
   import liquibase.database.Database;
   import liquibase.database.core.PostgresDatabase;
   import liquibase.exception.ValidationErrors;
   import liquibase.sql.Sql;
   import liquibase.sql.UnparsedSql;
   import liquibase.sqlgenerator.SqlGenerator;
   import liquibase.sqlgenerator.SqlGeneratorChain;
  import liquibase.statement.core.DropSequenceStatement;
  
  public class DropSequenceGenerator extends AbstractSqlGenerator<DropSequenceStatement> {
  
      @Override
      public boolean supports(DropSequenceStatement statement, Database database) {
          return database.supportsSequences();
      }
  
      public ValidationErrors validate(DropSequenceStatement dropSequenceStatement, Database database,
              SqlGeneratorChain sqlGeneratorChain) {
          ValidationErrors validationErrors = new ValidationErrors();
          validationErrors.checkRequiredField("sequenceName", dropSequenceStatement.getSequenceName());
          return validationErrors;
      }
  
      public Sql[] generateSql(DropSequenceStatement statement, Database database, SqlGeneratorChain sqlGeneratorChain) {
          String sql = "DROP SEQUENCE "
                  + database.escapeSequenceName(statement.getSchemaName(), statement.getSequenceName());
          if (database instanceof PostgresDatabase) {
              sql += " CASCADE";
          }
  
          return new Sql[] { new UnparsedSql(sql) };
      }
  }