code: public ImageIcon getCacheValue(Object objKey)
      {
          if (m_hmCache == null)
              return null;
          if (objKey == null)
              return null;
          Class<?> classKey = this.getField().getDataClass();
          objKey = this.convertKey(objKey, classKey);
          return (ImageIcon)m_hmCache.get(objKey);
      }
docs: Get the cache value.
  @param objKey The raw key value.
  @return The value associated with this key.