package liquibase.ext.spatial.sqlgenerator;
   
   import java.util.ArrayList;
   import java.util.Arrays;
   import java.util.List;
   
   import liquibase.database.Database;
   import liquibase.database.core.OracleDatabase;
   import liquibase.exception.ValidationErrors;
  import liquibase.sql.Sql;
  import liquibase.sql.UnparsedSql;
  import liquibase.sqlgenerator.SqlGeneratorChain;
  import liquibase.sqlgenerator.core.AbstractSqlGenerator;
  import liquibase.statement.core.DropTableStatement;
  import liquibase.structure.core.Table;
  import liquibase.structure.core.View;
  
  /**
   * <code>DropSpatialTableGeneratorOracle</code> generates the SQL statement for cleaning up any
   * metadata prior to dropping the table.
   */
  public class DropSpatialTableGeneratorOracle extends AbstractSqlGenerator<DropTableStatement> {
     @Override
     public boolean supports(final DropTableStatement statement, final Database database) {
        return database instanceof OracleDatabase;
     }
  
     @Override
     public int getPriority() {
        return super.getPriority() + 1;
     }
  
     @Override
     public ValidationErrors validate(final DropTableStatement statement, final Database database,
           final SqlGeneratorChain sqlGeneratorChain) {
        return sqlGeneratorChain.validate(statement, database);
     }
  
     @Override
     public Sql[] generateSql(final DropTableStatement statement, final Database database,
           final SqlGeneratorChain sqlGeneratorChain) {
        final StringBuilder sql = new StringBuilder();
        sql.append("DELETE FROM user_sdo_geom_metadata ");
        sql.append("WHERE table_name = '").append(
              database.correctObjectName(statement.getTableName(), Table.class));
        sql.append("'");
        final UnparsedSql deleteMetadata = new UnparsedSql(sql.toString(),
              new View().setName("user_sdo_geom_metadata"));
  
        // First delete the record then perform the standard behavior.
        final List<Sql> list = new ArrayList<Sql>();
        list.add(deleteMetadata);
        list.addAll(Arrays.asList(sqlGeneratorChain.generateSql(statement, database)));
        return list.toArray(new Sql[list.size()]);
     }
  }