# Package org.apache.storm.utils

- Interface Summary
  Interface | Description
  --- | ---
  IPredicate<T> | This interface is implemented by classes, instances of which can be passed into certain Util functions which test some collection for elements matching the IPredicate.
  IVersionInfo | Implementation of VersionInfo that uses a properties file to get the VersionInfo.
  JCQueue.Consumer |
  JCQueue.ExitCondition |
  LruMap.CacheEvictionCallback<K,​V> |
  NimbusClient.WithNimbus | An interface to allow callbacks with a thrift nimbus client.
  RotatingMap.ExpiredCallback<K,​V> |
  ShellCommandRunner | Contains convenience functions for running shell commands for cases that are too simple to need a full `ShellUtils` implementation.
  ShellLogHandler | Handle logging from non-JVM processes.
  SupervisorIfaceFactory |
  TimeCacheMap.ExpiredCallback<K,​V> |

- Class Summary
  Class | Description
  --- | ---
  BatchHelper |
  BufferFileInputStream |
  BufferInputStream |
  ConfigUtils |
  CRC32OutputStream |
  CuratorUtils |
  DaemonConfigValidation |
  DaemonConfigValidation.NumaEntryValidator |
  DefaultShellLogHandler | Default implementation of `ShellLogHandler`.
  DRPCClient |
  DRPCClient.LocalOverride |
  EnumUtil |
  EquivalenceUtils |
  ExtendedThreadPoolExecutor |
  HadoopLoginUtil | UserGroupInformation#loginUserFromKeytab(String, String) changes the static fields of UserGroupInformation, especially the current logged-in user, and UserGroupInformation itself is not thread-safe.
  InprocMessaging |
  JCQueue |
  JCQueueMetrics |
  KeyedRoundRobinQueue<V> |
  ListDelegate |
  LocalState | A simple, durable, atomic K/V database.
  LruMap<A,​B> |
  Monitor |
  MutableInt |
  MutableLong |
  MutableObject |
  NimbusClient | Client used for connecting to nimbus.
  NimbusClient.Builder |
  NimbusClient.LocalOverride |
  ObjectReader |
  ReflectionUtils |
  RegisteredGlobalState | This class is used as part of testing Storm.
  RotatingMap<K,​V> | Expires keys that have not been updated in the configured number of seconds.
  SecurityUtils |
  ServerConfigUtils |
  ServerUtils |
  ServiceRegistry |
  ShellBoltMessageQueue | A data structure for ShellBolt which includes two queues (FIFO), which one is for task ids (unbounded), another one is for bolt msg (bounded).
  ShellCommandRunnerImpl |
  ShellProcess |
  ShellUtils |
  ShellUtils.ShellCommandExecutor | A simple shell command executor.
  SimpleVersion | Take a version string and parse out a Major.Minor version
  StormBoundedExponentialBackoffRetry |
  StormCommonInstaller |
  SupervisorClient | Client for interacting with Supervisor server, now we use supervisor server mainly for cases below.
  SupervisorClient.Builder |
  ThriftTopologyUtils |
  Time | This class implements time simulation support.
  Time.SimulatedTime |
  TimeCacheMap<K,​V> | Deprecated.
  TopologySpoutLag |
  TransferDrainer |
  TupleUtils |
  Utils |
  Utils.SmartThread | A thread that can answer if it is sleeping in the case of simulated time.
  Utils.UptimeComputer |
  VersionedStore |
  VersionInfo |
  WebAppUtils |
  WindowedTimeThrottler |
  WritableUtils |
  ZookeeperAuthInfo |
  ZookeeperServerCnxnFactory |

- Enum Summary
  Enum | Description
  --- | ---
  ShellUtils.OSType | OSType detection.

- Exception Summary
  Exception | Description
  --- | ---
  DisallowedStrategyException |
  NimbusLeaderNotFoundException | This exception class is used to signify a problem with nimbus leader identification.
  ShellUtils.ExitCodeException | This is an IOException with exit code added.
  WrappedAlreadyAliveException | Wraps the generated TException to allow getMessage() to return a valid string.
  WrappedAuthorizationException | Wraps the generated TException to allow getMessage() to return a valid string.
  WrappedDRPCExecutionException | Wraps the generated TException to allow getMessage() to return a valid string.
  WrappedHBExecutionException | Wraps the generated TException to allow getMessage() to return a valid string.
  WrappedIllegalStateException |
  WrappedInvalidTopologyException | Wraps the generated TException to allow getMessage() to return a valid string.
  WrappedKeyAlreadyExistsException | Wraps the generated TException to allow getMessage() to return a valid string.
  WrappedKeyNotFoundException | Wraps the generated TException to allow getMessage() to return a valid string.
  WrappedNotAliveException | Wraps the generated TException to allow getMessage() to return a valid string.