code: @Override
      protected void _from(ObjectInput in) throws IOException,
              ClassNotFoundException {
          // 1: read number of stmts
          final int stmts = in.readInt();
          statements = sizedArrayList(stmts);
          for (int i = 0; i < stmts; i++) {
              TableStatement ts = new TableStatement();
              // 1: read each table statement
              ts.readExternal(in);
              // 2: read the relevant document index
              final int did = in.readInt();
              // 3: read the statement
              final Statement statement = readStatement(in);
              addStatement(ts, statement, did);
          }
      }
docs: {@inheritDoc}