# Class NioReceiver

java.lang.Object
org.apache.catalina.tribes.transport.ReceiverBase
org.apache.catalina.tribes.transport.nio.NioReceiver

All Implemented Interfaces:
  `Runnable, ChannelReceiver, Heartbeat, ListenCallback, NioReceiverMBean, RxTaskPool.TaskCreator`

public class NioReceiver extends ReceiverBase implements Runnable, NioReceiverMBean
NIO-based receiver for cluster communication.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected final Deque<Runnable>`
  `events`
  Queue of events to be processed by the selector thread.
  `protected long`
  `lastCheck`
  Timestamp of the last socket timeout check.
  `protected static final StringManager`
  `sm`
  The string manager for this package.

  ### Fields inherited from class ReceiverBase

  `OPTION_DIRECT_BUFFER`

  ### Fields inherited from interface ChannelReceiver

  `MAX_UDP_SIZE`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `NioReceiver()`
  Default constructor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `addEvent(Runnable event)`
  Adds a runnable event to the selector's event queue.
  `protected void`
  `bind()`
  Binds the server socket and datagram channels to their respective ports.
  `static void`
  `cancelledKey(SelectionKey key)`
  Handles a cancelled selection key by closing associated channels and cleaning up resources.
  `AbstractRxTask`
  `createRxTask()`
  Creates a new receive task.
  `void`
  `events()`
  Processes all pending events in the event queue.
  `protected void`
  `listen()`
  Get data from channel and store in byte array send it to cluster
  `protected void`
  `readDataFromSocket(SelectionKey key)`
  Sample data handler method for a channel with data ready to read.
  `protected void`
  `registerChannel(Selector selector, SelectableChannel channel, int ops, Object attach)`
  Register the given channel with the given selector for the given operations of interest
  `void`
  `run()`
  Start thread and listen
  `protected void`
  `socketTimeouts()`
  Checks for socket timeouts and handles expired connections.
  `void`
  `start()`
  Starts the receiver by creating the executor service and registering with JMX.
  `void`
  `stop()`
  Stops the receiver by shutting down the executor and unregistering from JMX.
  `protected void`
  `stopListening()`
  Close Selector.

  ### Methods inherited from class ReceiverBase

  `bind, bindUdp, doListen, getActiveCount, getAddress, getAutoBind, getBind, getChannel, getCompletedTaskCount, getDirect, getExecutor, getHost, getListener, getMaxIdleTime, getMaxTasks, getMaxThreads, getMessageListener, getMinTasks, getMinThreads, getOoBInline, getPoolSize, getPort, getRxBufSize, getSecurePort, getSelectorTimeout, getSoKeepAlive, getSoLingerOn, getSoLingerTime, getSoReuseAddress, getSoTrafficClass, getTaskCount, getTaskPool, getTcpNoDelay, getTimeout, getTxBufSize, getUdpPort, getUdpRxBufSize, getUdpTxBufSize, getUseBufferPool, getWorkerThreadOptions, heartbeat, isDaemon, isListening, messageDataReceived, setAddress, setAutoBind, setBind, setChannel, setDaemon, setDirect, setExecutor, setHost, setListen, setListener, setMaxIdleTime, setMaxTasks, setMaxThreads, setMessageListener, setMinTasks, setMinThreads, setOoBInline, setPool, setPort, setRxBufSize, setSecurePort, setSelectorTimeout, setSoKeepAlive, setSoLingerOn, setSoLingerTime, setSoReuseAddress, setSoTrafficClass, setTcpNoDelay, setTimeout, setTxBufSize, setUdpPort, setUdpRxBufSize, setUdpTxBufSize, setUseBufferPool`

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

  ### Methods inherited from interface NioReceiverMBean

  `getActiveCount, getAddress, getAutoBind, getCompletedTaskCount, getDirect, getMaxIdleTime, getMaxThreads, getMinThreads, getOoBInline, getPoolSize, getPort, getRxBufSize, getSecurePort, getSelectorTimeout, getSoKeepAlive, getSoLingerOn, getSoLingerTime, getSoReuseAddress, getTaskCount, getTcpNoDelay, getTimeout, getTxBufSize, getUdpPort, getUdpRxBufSize, getUdpTxBufSize, getUseBufferPool, isListening`

- ## Field Details

  - ### sm

    protected static final StringManager sm
    The string manager for this package.

  - ### events

    protected final Deque<Runnable> events
    Queue of events to be processed by the selector thread.

  - ### lastCheck

    protected long lastCheck
    Timestamp of the last socket timeout check.

- ## Constructor Details

  - ### NioReceiver

    public NioReceiver()
    Default constructor.

- ## Method Details

  - ### stop

    public void stop()
    Description copied from class: `ReceiverBase`
    Stops the receiver by shutting down the executor and unregistering from JMX.
    Specified by:
      `stop` in interface `ChannelReceiver`
    Overrides:
      `stop` in class `ReceiverBase`

  - ### start

    public void start() throws IOException
    Description copied from class: `ReceiverBase`
    Starts the receiver by creating the executor service and registering with JMX.
    Specified by:
      `start` in interface `ChannelReceiver`
    Overrides:
      `start` in class `ReceiverBase`
    Throws:
      `IOException` - if an I/O error occurs during startup

  - ### createRxTask

    public AbstractRxTask createRxTask()
    Description copied from interface: `RxTaskPool.TaskCreator`
    Creates a new receive task.
    Specified by:
      `createRxTask` in interface `RxTaskPool.TaskCreator`
    Returns:
      a new receive task instance

  - ### bind

    protected void bind() throws IOException
    Binds the server socket and datagram channels to their respective ports.
    Throws:
      `IOException` - If binding fails

  - ### addEvent

    public void addEvent(Runnable event)
    Adds a runnable event to the selector's event queue.
    Parameters:
      `event` - The event to add

  - ### events

    public void events()
    Processes all pending events in the event queue.

  - ### cancelledKey

    public static void cancelledKey(SelectionKey key)
    Handles a cancelled selection key by closing associated channels and cleaning up resources.
    Parameters:
      `key` - The cancelled selection key

  - ### socketTimeouts

    protected void socketTimeouts()
    Checks for socket timeouts and handles expired connections.

  - ### listen

    protected void listen() throws Exception
    Get data from channel and store in byte array send it to cluster
    Throws:
      `IOException` - IO error
      `Exception`

  - ### stopListening

    protected void stopListening()
    Close Selector.
    See Also:
      - `ReceiverBase.stop()`

  - ### registerChannel

    protected void registerChannel(Selector selector, SelectableChannel channel, int ops, Object attach) throws Exception
    Register the given channel with the given selector for the given operations of interest
    Parameters:
      `selector` - The selector to use
      `channel` - The channel
      `ops` - The operations to register
      `attach` - Attachment object
    Throws:
      `Exception` - IO error with channel

  - ### run

    public void run()
    Start thread and listen
    Specified by:
      `run` in interface `Runnable`

  - ### readDataFromSocket

    protected void readDataFromSocket(SelectionKey key) throws Exception
    Sample data handler method for a channel with data ready to read.
    Parameters:
      `key` - A SelectionKey object associated with a channel determined by the selector to be ready for reading. If the channel returns an EOF condition, it is closed here, which automatically invalidates the associated key. The selector will then de-register the channel on the next select call.
    Throws:
      `Exception` - IO error with channel