code: public ServiceInstanceQuery getContainQueryCriterion(String key){
          QueryCriterion c = new ContainQueryCriterion(key);
          addQueryCriterion(c);
          return this;
      }
docs: Get a metadata contain QueryCriterion.
  
  Add a QueryCriterion to check ServiceInstance has the
  the specified metadata.
  
  @param key
  the metadata key.
  @return
  the ServiceInstanceQuery.