code: public boolean containsEntityEntry(String entityName) {
          if (StringUtils.isBlank(entityName)) {
              throw new IllegalArgumentException("entityName cannot be null or empty.");
          }
          return entries.containsKey(entityName);
      }
docs: /* (non-Javadoc)
  @see com.google.code.siren4j.converter.ResourceRegistry#containsEntityEntry(java.lang.String)