/** Expand the current node and return the list of leaves (MaterialVO objects). */
 private ArrayList getComponents(DefaultMutableTreeNode node) {
   ArrayList list = new ArrayList();
   for (int i = 0; i < node.getChildCount(); i++)
     list.addAll(getComponents((DefaultMutableTreeNode) node.getChildAt(i)));
   if (node.isLeaf()) list.add(node.getUserObject());
   return list;
 }
  /**
   * Check if components required by specified products are available.
   *
   * @param products list of ProdOrderProductVO objects
   * @params compAltComps collection of <component item code,HashSet of alternative component item
   *     codes>; filled by this method (and given back by reference)
   * @return VOListResponse of ProdOrderComponentVO objects
   */
  public final Response checkComponentsAvailability(
      Connection conn,
      Hashtable compAltComps,
      ArrayList products,
      UserSessionParameters userSessionPars,
      HttpServletRequest request,
      HttpServletResponse response,
      HttpSession userSession,
      ServletContext context) {
    String serverLanguageId = ((JAIOUserSessionParameters) userSessionPars).getServerLanguageId();
    try {

      // retrieve internationalization settings (Resources object)...
      ServerResourcesFactory factory =
          (ServerResourcesFactory) context.getAttribute(Controller.RESOURCES_FACTORY);
      Resources resources = factory.getResources(userSessionPars.getLanguageId());

      if (products.size() == 0) {
        return new VOListResponse(new ArrayList(), false, 0);
      }

      // fill in comps hashtable with the collection of required components...
      ItemPK pk = null;
      ProdOrderProductVO prodVO = null;
      ArrayList components = null;
      MaterialVO compVO = null;
      Response res = null;
      ProdOrderComponentVO componentVO = null;
      Hashtable comps =
          new Hashtable(); // collection of <component item code,ProdOrderComponentVO object>
      for (int i = 0; i < products.size(); i++) {
        // retrieve bill of materials for each product...
        prodVO = (ProdOrderProductVO) products.get(i);
        pk = new ItemPK(prodVO.getCompanyCodeSys01DOC23(), prodVO.getItemCodeItm01DOC23());
        res =
            bean.getBillOfMaterials(
                conn, pk, userSessionPars, request, response, userSession, context);
        if (res.isError()) {
          return res;
        }

        // extract components only (leaf nodes)...
        components =
            getComponents(
                (DefaultMutableTreeNode) ((TreeModel) ((VOResponse) res).getVo()).getRoot());
        for (int j = 0; j < components.size(); j++) {
          compVO = (MaterialVO) components.get(j);
          componentVO = (ProdOrderComponentVO) comps.get(compVO.getItemCodeItm01ITM03());
          if (componentVO == null) {
            componentVO = new ProdOrderComponentVO();
            comps.put(compVO.getItemCodeItm01ITM03(), componentVO);
            componentVO.setAvailableQty(new BigDecimal(0));
            componentVO.setCompanyCodeSys01DOC24(compVO.getCompanyCodeSys01ITM03());
            componentVO.setDescriptionSYS10(compVO.getDescriptionSYS10());
            componentVO.setDocNumberDOC24(prodVO.getDocNumberDOC23());
            componentVO.setDocYearDOC24(prodVO.getDocYearDOC23());
            componentVO.setItemCodeItm01DOC24(compVO.getItemCodeItm01ITM03());
            componentVO.setMinSellingQtyUmCodeReg02ITM01(compVO.getMinSellingQtyUmCodeReg02ITM01());
            componentVO.setQtyDOC24(new BigDecimal(0));
          }
          componentVO.setQtyDOC24(
              componentVO.getQtyDOC24().add(compVO.getQtyITM03().multiply(prodVO.getQtyDOC23())));
        }
      }

      // check components availability in the specified warehouse...
      Enumeration en = comps.keys();
      GridParams gridParams = new GridParams();
      gridParams
          .getOtherGridParams()
          .put(ApplicationConsts.COMPANY_CODE_SYS01, prodVO.getCompanyCodeSys01DOC23());
      gridParams
          .getOtherGridParams()
          .put(ApplicationConsts.WAREHOUSE_CODE, prodVO.getWarehouseCodeWar01DOC22());
      gridParams.getOtherGridParams().put(ApplicationConsts.LOAD_ALL, Boolean.TRUE);
      ItemAvailabilityVO availVO = null;
      BigDecimal availability, altAvailability, delta;
      String itemCode = null;
      ArrayList list, availList;
      AltComponentVO altVO = null;
      ArrayList alternativeComps = new ArrayList();
      ArrayList compsToRemove = new ArrayList();
      ProdOrderComponentVO altComponentVO = null;
      HashSet altCodes = null; // list of alternative component item codes...
      BigDecimal altQty = null;
      while (en.hasMoreElements()) {
        itemCode = en.nextElement().toString();
        componentVO = (ProdOrderComponentVO) comps.get(itemCode);

        gridParams
            .getOtherGridParams()
            .put(
                ApplicationConsts.ITEM_PK, new ItemPK(prodVO.getCompanyCodeSys01DOC23(), itemCode));
        res =
            avail.executeCommand(
                gridParams, userSessionPars, request, response, userSession, context);
        if (res.isError()) return res;

        availList = ((VOListResponse) res).getRows();
        componentVO.setAvailabilities(availList);
        availability = new BigDecimal(0);
        for (int i = 0; i < availList.size(); i++) {
          availVO = (ItemAvailabilityVO) availList.get(i);
          availability = availability.add(availVO.getAvailableQtyWAR03());
        }
        componentVO.setAvailableQty(availability);

        if (componentVO.getQtyDOC24().doubleValue() > componentVO.getAvailableQty().doubleValue()) {
          // check if there exist some alternative component...
          res =
              altComps.executeCommand(
                  gridParams, userSessionPars, request, response, userSession, context);
          if (res.isError()) return res;
          list = ((VOListResponse) res).getRows();
          for (int i = 0; i < list.size(); i++) {
            altVO = (AltComponentVO) list.get(i);
            gridParams
                .getOtherGridParams()
                .put(
                    ApplicationConsts.ITEM_PK,
                    new ItemPK(prodVO.getCompanyCodeSys01DOC23(), altVO.getItemCodeItm01ITM04()));
            res =
                avail.executeCommand(
                    gridParams, userSessionPars, request, response, userSession, context);
            if (res.isError()) return res;
            availList = ((VOListResponse) res).getRows();
            altAvailability = new BigDecimal(0);
            for (int j = 0; j < availList.size(); j++) {
              availVO = (ItemAvailabilityVO) availList.get(j);
              altAvailability = altAvailability.add(availVO.getAvailableQtyWAR03());
            }
            if (altAvailability.doubleValue() > 0) {
              altComponentVO = new ProdOrderComponentVO();
              altComponentVO.setAvailabilities(availList);
              altComponentVO.setAvailableQty(altAvailability);
              altComponentVO.setCompanyCodeSys01DOC24(altVO.getCompanyCodeSys01ITM04());
              altComponentVO.setDescriptionSYS10(altVO.getDescriptionSYS10());
              altComponentVO.setDocNumberDOC24(prodVO.getDocNumberDOC23());
              altComponentVO.setDocYearDOC24(prodVO.getDocYearDOC23());
              altComponentVO.setItemCodeItm01DOC24(altVO.getItemCodeItm01ITM04());
              altComponentVO.setMinSellingQtyUmCodeReg02ITM01(
                  altVO.getMinSellingQtyUmCodeReg02ITM01());
              altQty =
                  conv.convertQty(
                      altVO.getMinSellingQtyUmCodeReg02ITM01(),
                      componentVO.getMinSellingQtyUmCodeReg02ITM01(),
                      altAvailability,
                      userSessionPars,
                      request,
                      response,
                      userSession,
                      context);
              if (componentVO.getQtyDOC24().subtract(availability).doubleValue()
                  > altQty.doubleValue()) {
                delta = altQty;
                altComponentVO.setQtyDOC24(altAvailability);
              } else {
                delta = componentVO.getQtyDOC24();
                altComponentVO.setQtyDOC24(
                    conv.convertQty(
                        componentVO.getMinSellingQtyUmCodeReg02ITM01(),
                        altVO.getMinSellingQtyUmCodeReg02ITM01(),
                        delta,
                        userSessionPars,
                        request,
                        response,
                        userSession,
                        context));
              }
              componentVO.setQtyDOC24(componentVO.getQtyDOC24().subtract(delta));
              alternativeComps.add(altComponentVO);

              altCodes = (HashSet) compAltComps.get(itemCode);
              if (altCodes == null) {
                altCodes = new HashSet();
                compAltComps.put(itemCode, altCodes);
              }
              altCodes.add(altVO.getItemCodeItm01ITM04());

              if (componentVO.getQtyDOC24().doubleValue() == 0) {
                compsToRemove.add(componentVO);
                break;
              }
              if (componentVO.getQtyDOC24().subtract(availability).doubleValue() == 0) break;
            }
          }
        }
      }

      list = new ArrayList(comps.values());
      list.addAll(alternativeComps);
      list.removeAll(compsToRemove);
      return new VOListResponse(list, false, list.size());
    } catch (Throwable ex) {
      Logger.error(
          userSessionPars.getUsername(),
          this.getClass().getName(),
          "checkComponentsAvailability",
          "Error while retrieving components availability for the specified production order",
          ex);
      return new ErrorResponse(ex.getMessage());
    }
  }