protected final synchronized DocCollection getDocCollection() {
    if (docCollection == null) {
      ZkStateReader zkStateReader = getCloudSolrServer().getZkStateReader();
      docCollection = zkStateReader.getClusterState().getCollection(collection);

      // do basic checks once
      DocRouter docRouter = docCollection.getRouter();
      if (docRouter instanceof ImplicitDocRouter)
        throw new IllegalStateException(
            "Implicit document routing not supported by this Partitioner!");
      Collection<Slice> shards = getDocCollection().getSlices();
      if (shards == null || shards.size() == 0)
        throw new IllegalStateException(
            "Collection '" + collection + "' does not have any shards!");
    }
    return docCollection;
  }
  @Override
  public int getPartition(Object o) {

    Object docId = null;
    if (o instanceof SolrInputDocument) {
      SolrInputDocument doc = (SolrInputDocument) o;
      docId = doc.getFieldValue(idField);
      if (docId == null)
        throw new IllegalArgumentException(
            "SolrInputDocument must contain a non-null value for " + idField);
    } else {
      docId = o;
    }

    if (!(docId instanceof String))
      throw new IllegalArgumentException(
          "Only String document IDs are supported by this Partitioner!");

    DocCollection dc = getDocCollection();
    Slice slice = dc.getRouter().getTargetSlice((String) docId, null, null, null, dc);
    return getShardIndex(slice.getName(), dc);
  }
 public String getShardId(String docId) {
   DocCollection dc = getDocCollection();
   Slice slice = dc.getRouter().getTargetSlice(docId, null, null, null, dc);
   return slice.getName();
 }
  protected NamedList<Object> sendRequest(SolrRequest request)
      throws SolrServerException, IOException {
    connect();

    ClusterState clusterState = zkStateReader.getClusterState();

    boolean sendToLeaders = false;
    List<String> replicas = null;

    if (request instanceof IsUpdateRequest) {
      if (request instanceof UpdateRequest) {
        NamedList<Object> response = directUpdate((AbstractUpdateRequest) request, clusterState);
        if (response != null) {
          return response;
        }
      }
      sendToLeaders = true;
      replicas = new ArrayList<>();
    }

    SolrParams reqParams = request.getParams();
    if (reqParams == null) {
      reqParams = new ModifiableSolrParams();
    }
    List<String> theUrlList = new ArrayList<>();
    if (request.getPath().equals("/admin/collections")
        || request.getPath().equals("/admin/cores")) {
      Set<String> liveNodes = clusterState.getLiveNodes();
      for (String liveNode : liveNodes) {
        theUrlList.add(zkStateReader.getBaseUrlForNodeName(liveNode));
      }
    } else {
      String collection = reqParams.get(UpdateParams.COLLECTION, defaultCollection);

      if (collection == null) {
        throw new SolrServerException(
            "No collection param specified on request and no default collection has been set.");
      }

      Set<String> collectionsList = getCollectionList(clusterState, collection);
      if (collectionsList.size() == 0) {
        throw new SolrException(ErrorCode.BAD_REQUEST, "Could not find collection: " + collection);
      }

      String shardKeys = reqParams.get(ShardParams._ROUTE_);
      if (shardKeys == null) {
        shardKeys = reqParams.get(ShardParams.SHARD_KEYS); // deprecated
      }

      // TODO: not a big deal because of the caching, but we could avoid looking
      // at every shard
      // when getting leaders if we tweaked some things

      // Retrieve slices from the cloud state and, for each collection
      // specified,
      // add it to the Map of slices.
      Map<String, Slice> slices = new HashMap<>();
      for (String collectionName : collectionsList) {
        DocCollection col = getDocCollection(clusterState, collectionName);
        Collection<Slice> routeSlices = col.getRouter().getSearchSlices(shardKeys, reqParams, col);
        ClientUtils.addSlices(slices, collectionName, routeSlices, true);
      }
      Set<String> liveNodes = clusterState.getLiveNodes();

      List<String> leaderUrlList = null;
      List<String> urlList = null;
      List<String> replicasList = null;

      // build a map of unique nodes
      // TODO: allow filtering by group, role, etc
      Map<String, ZkNodeProps> nodes = new HashMap<>();
      List<String> urlList2 = new ArrayList<>();
      for (Slice slice : slices.values()) {
        for (ZkNodeProps nodeProps : slice.getReplicasMap().values()) {
          ZkCoreNodeProps coreNodeProps = new ZkCoreNodeProps(nodeProps);
          String node = coreNodeProps.getNodeName();
          if (!liveNodes.contains(coreNodeProps.getNodeName())
              || !coreNodeProps.getState().equals(ZkStateReader.ACTIVE)) continue;
          if (nodes.put(node, nodeProps) == null) {
            if (!sendToLeaders || (sendToLeaders && coreNodeProps.isLeader())) {
              String url;
              if (reqParams.get(UpdateParams.COLLECTION) == null) {
                url =
                    ZkCoreNodeProps.getCoreUrl(
                        nodeProps.getStr(ZkStateReader.BASE_URL_PROP), defaultCollection);
              } else {
                url = coreNodeProps.getCoreUrl();
              }
              urlList2.add(url);
            } else if (sendToLeaders) {
              String url;
              if (reqParams.get(UpdateParams.COLLECTION) == null) {
                url =
                    ZkCoreNodeProps.getCoreUrl(
                        nodeProps.getStr(ZkStateReader.BASE_URL_PROP), defaultCollection);
              } else {
                url = coreNodeProps.getCoreUrl();
              }
              replicas.add(url);
            }
          }
        }
      }

      if (sendToLeaders) {
        leaderUrlList = urlList2;
        replicasList = replicas;
      } else {
        urlList = urlList2;
      }

      if (sendToLeaders) {
        theUrlList = new ArrayList<>(leaderUrlList.size());
        theUrlList.addAll(leaderUrlList);
      } else {
        theUrlList = new ArrayList<>(urlList.size());
        theUrlList.addAll(urlList);
      }
      if (theUrlList.isEmpty()) {
        throw new SolrException(
            SolrException.ErrorCode.INVALID_STATE, "Not enough nodes to handle the request");
      }

      Collections.shuffle(theUrlList, rand);
      if (sendToLeaders) {
        ArrayList<String> theReplicas = new ArrayList<>(replicasList.size());
        theReplicas.addAll(replicasList);
        Collections.shuffle(theReplicas, rand);
        theUrlList.addAll(theReplicas);
      }
    }

    LBHttpSolrServer.Req req = new LBHttpSolrServer.Req(request, theUrlList);
    LBHttpSolrServer.Rsp rsp = lbServer.request(req);
    return rsp.getResponse();
  }
  private NamedList<Object> directUpdate(AbstractUpdateRequest request, ClusterState clusterState)
      throws SolrServerException {
    UpdateRequest updateRequest = (UpdateRequest) request;
    ModifiableSolrParams params = (ModifiableSolrParams) request.getParams();
    ModifiableSolrParams routableParams = new ModifiableSolrParams();
    ModifiableSolrParams nonRoutableParams = new ModifiableSolrParams();

    if (params != null) {
      nonRoutableParams.add(params);
      routableParams.add(params);
      for (String param : NON_ROUTABLE_PARAMS) {
        routableParams.remove(param);
      }
    }

    String collection = nonRoutableParams.get(UpdateParams.COLLECTION, defaultCollection);
    if (collection == null) {
      throw new SolrServerException(
          "No collection param specified on request and no default collection has been set.");
    }

    // Check to see if the collection is an alias.
    Aliases aliases = zkStateReader.getAliases();
    if (aliases != null) {
      Map<String, String> collectionAliases = aliases.getCollectionAliasMap();
      if (collectionAliases != null && collectionAliases.containsKey(collection)) {
        collection = collectionAliases.get(collection);
      }
    }

    DocCollection col = getDocCollection(clusterState, collection);

    DocRouter router = col.getRouter();

    if (router instanceof ImplicitDocRouter) {
      // short circuit as optimization
      return null;
    }

    // Create the URL map, which is keyed on slice name.
    // The value is a list of URLs for each replica in the slice.
    // The first value in the list is the leader for the slice.
    Map<String, List<String>> urlMap = buildUrlMap(col);
    if (urlMap == null) {
      // we could not find a leader yet - use unoptimized general path
      return null;
    }

    NamedList<Throwable> exceptions = new NamedList<>();
    NamedList<NamedList> shardResponses = new NamedList<>();

    Map<String, LBHttpSolrServer.Req> routes =
        updateRequest.getRoutes(router, col, urlMap, routableParams, this.idField);
    if (routes == null) {
      return null;
    }

    long start = System.nanoTime();

    if (parallelUpdates) {
      final Map<String, Future<NamedList<?>>> responseFutures = new HashMap<>(routes.size());
      for (final Map.Entry<String, LBHttpSolrServer.Req> entry : routes.entrySet()) {
        final String url = entry.getKey();
        final LBHttpSolrServer.Req lbRequest = entry.getValue();
        responseFutures.put(
            url,
            threadPool.submit(
                new Callable<NamedList<?>>() {
                  @Override
                  public NamedList<?> call() throws Exception {
                    return lbServer.request(lbRequest).getResponse();
                  }
                }));
      }

      for (final Map.Entry<String, Future<NamedList<?>>> entry : responseFutures.entrySet()) {
        final String url = entry.getKey();
        final Future<NamedList<?>> responseFuture = entry.getValue();
        try {
          shardResponses.add(url, responseFuture.get());
        } catch (InterruptedException e) {
          Thread.currentThread().interrupt();
          throw new RuntimeException(e);
        } catch (ExecutionException e) {
          exceptions.add(url, e.getCause());
        }
      }

      if (exceptions.size() > 0) {
        throw new RouteException(ErrorCode.SERVER_ERROR, exceptions, routes);
      }
    } else {
      for (Map.Entry<String, LBHttpSolrServer.Req> entry : routes.entrySet()) {
        String url = entry.getKey();
        LBHttpSolrServer.Req lbRequest = entry.getValue();
        try {
          NamedList<Object> rsp = lbServer.request(lbRequest).getResponse();
          shardResponses.add(url, rsp);
        } catch (Exception e) {
          throw new SolrServerException(e);
        }
      }
    }

    UpdateRequest nonRoutableRequest = null;
    List<String> deleteQuery = updateRequest.getDeleteQuery();
    if (deleteQuery != null && deleteQuery.size() > 0) {
      UpdateRequest deleteQueryRequest = new UpdateRequest();
      deleteQueryRequest.setDeleteQuery(deleteQuery);
      nonRoutableRequest = deleteQueryRequest;
    }

    Set<String> paramNames = nonRoutableParams.getParameterNames();

    Set<String> intersection = new HashSet<>(paramNames);
    intersection.retainAll(NON_ROUTABLE_PARAMS);

    if (nonRoutableRequest != null || intersection.size() > 0) {
      if (nonRoutableRequest == null) {
        nonRoutableRequest = new UpdateRequest();
      }
      nonRoutableRequest.setParams(nonRoutableParams);
      List<String> urlList = new ArrayList<>();
      urlList.addAll(routes.keySet());
      Collections.shuffle(urlList, rand);
      LBHttpSolrServer.Req req = new LBHttpSolrServer.Req(nonRoutableRequest, urlList);
      try {
        LBHttpSolrServer.Rsp rsp = lbServer.request(req);
        shardResponses.add(urlList.get(0), rsp.getResponse());
      } catch (Exception e) {
        throw new SolrException(ErrorCode.SERVER_ERROR, urlList.get(0), e);
      }
    }

    long end = System.nanoTime();

    RouteResponse rr = condenseResponse(shardResponses, (long) ((end - start) / 1000000));
    rr.setRouteResponses(shardResponses);
    rr.setRoutes(routes);
    return rr;
  }
  public int createSubRequests(ResponseBuilder rb) throws IOException {
    SolrParams params = rb.req.getParams();
    String id1[] = params.getParams("id");
    String ids[] = params.getParams("ids");

    if (id1 == null && ids == null) {
      return ResponseBuilder.STAGE_DONE;
    }

    List<String> allIds = new ArrayList<String>();
    if (id1 != null) {
      for (String s : id1) {
        allIds.add(s);
      }
    }
    if (ids != null) {
      for (String s : ids) {
        allIds.addAll(StrUtils.splitSmart(s, ",", true));
      }
    }

    // TODO: handle collection=...?

    ZkController zkController =
        rb.req.getCore().getCoreDescriptor().getCoreContainer().getZkController();

    // if shards=... then use that
    if (zkController != null && params.get("shards") == null) {
      CloudDescriptor cloudDescriptor = rb.req.getCore().getCoreDescriptor().getCloudDescriptor();

      String collection = cloudDescriptor.getCollectionName();
      ClusterState clusterState = zkController.getClusterState();
      DocCollection coll = clusterState.getCollection(collection);

      Map<String, List<String>> sliceToId = new HashMap<String, List<String>>();
      for (String id : allIds) {
        Slice slice = coll.getRouter().getTargetSlice(id, null, params, coll);

        List<String> idsForShard = sliceToId.get(slice.getName());
        if (idsForShard == null) {
          idsForShard = new ArrayList<String>(2);
          sliceToId.put(slice.getName(), idsForShard);
        }
        idsForShard.add(id);
      }

      for (Map.Entry<String, List<String>> entry : sliceToId.entrySet()) {
        String shard = entry.getKey();
        String shardIdList = StrUtils.join(entry.getValue(), ',');

        ShardRequest sreq = new ShardRequest();

        sreq.purpose = 1;
        // sreq.shards = new String[]{shard};    // TODO: would be nice if this would work...
        sreq.shards = sliceToShards(rb, collection, shard);
        sreq.actualShards = sreq.shards;
        sreq.params = new ModifiableSolrParams();
        sreq.params.set(
            ShardParams.SHARDS_QT,
            "/get"); // TODO: how to avoid hardcoding this and hit the same handler?
        sreq.params.set("distrib", false);
        sreq.params.set("ids", shardIdList);

        rb.addRequest(this, sreq);
      }
    } else {
      String shardIdList = StrUtils.join(allIds, ',');
      ShardRequest sreq = new ShardRequest();

      sreq.purpose = 1;
      sreq.shards = null; // ALL
      sreq.actualShards = sreq.shards;
      sreq.params = new ModifiableSolrParams();
      sreq.params.set(
          ShardParams.SHARDS_QT,
          "/get"); // TODO: how to avoid hardcoding this and hit the same handler?
      sreq.params.set("distrib", false);
      sreq.params.set("ids", shardIdList);

      rb.addRequest(this, sreq);
    }

    return ResponseBuilder.STAGE_DONE;
  }