Class ASqlHandler

core/src/main/java/io/ddf/etl/ASqlHandler.java:32–223

/**
 */
public abstract class ASqlHandler extends ADDFFunctionalGroupHandler implements IHandleSql {

  public ASqlHandler(DDF theDDF) {
    super(theDDF);
  }

  /**
   * @brief Show tables in the database.
   * @return The table names.
   */
  public SqlResult showTables() throws DDFException {
    List<String> tableNames = new ArrayList<String>();
    for (DDF ddf : this.getManager().listDDFs()) {
      if (ddf.getName() != null) {
        tableNames.add(ddf.getName());
      }
    }
    List<Column> columnList = new ArrayList<Column>();
    columnList.add(new Column("table_name", Schema.ColumnType.STRING));
    Schema schema = new Schema("tables", columnList);
    return new SqlResult(schema, tableNames);
  }

  /**
   * @brief Get the column information of this table.
   * @param name The URI or the name of the ddf.
   * @param namespace The namespace.
   * @return The column information.
   * @throws DDFException
   */
  private SqlResult describeTable(String name, String namespace)
          throws DDFException {
    DDF ddf = null;
    try {
        ddf = this.getManager().getOrRestoreDDFUri(name);
    } catch (Exception e) {
        if (null == namespace) {
            throw new DDFException("ERROR: there is no ddf " + name);
        }
        try {
            mLog.info("trying to restore " + "ddf://" + namespace + "/" + name);
            ddf = this.getManager().getOrRestoreDDFUri("ddf://" + namespace + "/" + name);
        } catch (Exception e2) {
            throw new DDFException("ERROR: there is no ddf " + name);
        }
    }

    int colSize = ddf.getNumColumns();
    List<String> ret = new ArrayList<String>();
    for (int colIdx = 0; colIdx < colSize; ++colIdx) {
      Schema.Column col = ddf.getColumn(ddf.getColumnName(colIdx));
      ret.add(col.getName().concat("\t").concat(col.getType().toString()
              .toLowerCase()));
    }
    List<Column> columnList = new ArrayList<Column>();
    columnList.add(new Column("column_name", Schema.ColumnType.STRING));
    columnList.add(new Column("value_type", Schema.ColumnType.STRING));
    Schema schema = new Schema("table_info", columnList);