code: public PurchaseHostReservationRequest withHostIdSet(String... hostIdSet) {
          if (this.hostIdSet == null) {
              setHostIdSet(new com.amazonaws.internal.SdkInternalList<String>(hostIdSet.length));
          }
          for (String ele : hostIdSet) {
              this.hostIdSet.add(ele);
          }
          return this;
      }
docs: <p>
  The IDs of the Dedicated Hosts with which the reservation will be associated.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setHostIdSet(java.util.Collection)} or {@link #withHostIdSet(java.util.Collection)} if you want to
  override the existing values.
  </p>
  
  @param hostIdSet
  The IDs of the Dedicated Hosts with which the reservation will be associated.
  @return Returns a reference to this object so that method calls can be chained together.