@Override
  public String toString() {
    Object[] locValues = getFieldValues();
    String[] names = getFieldNames();
    StringBuilder buf = new StringBuilder();
    buf.append("struct(");
    for (int i = 0; i < locValues.length; i++) {
      if (i > 0) {
        buf.append(",");
      }
      buf.append(names[i]);
      buf.append(":");
      buf.append(locValues[i]);
    }
    buf.append(")");
    return buf.toString();
  }
Helper method, Returns field values, in case of PdxInstance gets the domain objects.
geode-core/src/main/java/org/apache/geode/cache/query/internal/StructImpl.java