code: public void setActivityIds(java.util.Collection<String> activityIds) {
          if (activityIds == null) {
              this.activityIds = null;
              return;
          }
  
          this.activityIds = new com.amazonaws.internal.SdkInternalList<String>(activityIds);
      }
docs: <p>
  The activity IDs of the desired scaling activities. You can specify up to 50 IDs. If you omit this parameter, all
  activities for the past six weeks are described. If unknown activities are requested, they are ignored with no
  error. If you specify an Auto Scaling group, the results are limited to that group.
  </p>
  
  @param activityIds
  The activity IDs of the desired scaling activities. You can specify up to 50 IDs. If you omit this
  parameter, all activities for the past six weeks are described. If unknown activities are requested, they
  are ignored with no error. If you specify an Auto Scaling group, the results are limited to that group.