Method call

src/HBaseClient.java:1133–1156

(final ArrayList<Object> arg)

    return Deferred.group(d).addCallback(
      new Callback<Object, ArrayList<Object>>() {
        public Object call(final ArrayList<Object> arg) {
          // Normally, now that we've shutdown() every client, all our caches should
          // be empty since each shutdown() generates a DISCONNECTED event, which
          // causes RegionClientPipeline to call removeClientFromCache().
          HashMap<String, RegionClient> logme = null;
          synchronized (ip2client) {
            if (!ip2client.isEmpty()) {
              logme = new HashMap<String, RegionClient>(ip2client);
            }
          }
          if (logme != null) {
            // Putting this logging statement inside the synchronized block
            // can lead to a deadlock, since HashMap.toString() is going to
            // call RegionClient.toString() on each entry, and this locks the
            // client briefly.  Other parts of the code lock clients first and
            // the ip2client HashMap second, so this can easily deadlock.
            LOG.error("Some clients are left in the client cache and haven't"
                      + " been cleaned up: " + logme);
            logme = null;
            return disconnectEverything();  // Try again.
          }
          zkclient.disconnectZK();
          return arg;
        }
        public String toString() {
          return "wait " + size + " RegionClient.shutdown()";
        }