code: @Override
      public Set<JobKey> getJobKeys(GroupMatcher<JobKey> matcher, JedisCluster jedis) {
          Set<JobKey> jobKeys = new HashSet<>();
          if (matcher.getCompareWithOperator() == StringMatcher.StringOperatorName.EQUALS) {
              final String jobGroupSetKey = redisSchema.jobGroupSetKey(new JobKey("", matcher.getCompareToValue()));
              final Set<String> jobs = jedis.smembers(jobGroupSetKey);
              if (jobs != null) {
                  for (final String job : jobs) {
                      jobKeys.add(redisSchema.jobKey(job));
                  }
              }
          } else {
              List<Set<String>> jobGroups = new ArrayList<>();
              for (final String jobGroupSetKey : jedis.smembers(redisSchema.jobGroupsSet())) {
                  if (matcher.getCompareWithOperator().evaluate(redisSchema.jobGroup(jobGroupSetKey), matcher.getCompareToValue())) {
                      jobGroups.add(jedis.smembers(jobGroupSetKey));
                  }
              }
              for (Set<String> jobGroup : jobGroups) {
                  if (jobGroup != null) {
                      for (final String job : jobGroup) {
                          jobKeys.add(redisSchema.jobKey(job));
                      }
                  }
              }
          }
          return jobKeys;
      }
docs: Get the keys of all of the <code>{@link Job}</code> s that have the given group name.
  
  @param matcher the matcher with which to compare group names
  @param jedis   a thread-safe Redis connection
  @return the set of all JobKeys which have the given group name