NIOServerCnxnFactory (Apache ZooKeeper

java.lang.Object
- org.apache.zookeeper.server.ServerCnxnFactory
- - org.apache.zookeeper.server.NIOServerCnxnFactory

```
public class NIOServerCnxnFactory
extends ServerCnxnFactory
```
NIOServerCnxnFactory implements a multi-threaded ServerCnxnFactory using NIO non-blocking socket calls. Communication between threads is handled via queues. - 1 accept thread, which accepts new connections and assigns to a selector thread - 1-N selector threads, each of which selects on 1/N of the connections. The reason the factory supports more than one selector thread is that with large numbers of connections, select() itself can become a performance bottleneck. - 0-M socket I/O worker threads, which perform basic socket reads and writes. If configured with 0 worker threads, the selector threads do the socket I/O directly. - 1 connection expiration thread, which closes idle connections; this is necessary to expire connections on which no session is established. Typical (default) thread counts are: on a 32 core machine, 1 accept thread, 1 connection expiration thread, 4 selector threads, and 64 worker threads.

Field Summary

Fields
Modifier and Type	Field and Description
`protected int`	`maxClientCnxns`
`protected WorkerService`	`workerPool`
`static String`	`ZOOKEEPER_NIO_DIRECT_BUFFER_BYTES` Default: 64kB
`static String`	`ZOOKEEPER_NIO_NUM_SELECTOR_THREADS` With 500 connections to an observer with watchers firing on each, is unable to exceed 1GigE rates with only 1 selector.
`static String`	`ZOOKEEPER_NIO_NUM_WORKER_THREADS` Default: 2 * numCores
`static String`	`ZOOKEEPER_NIO_SESSIONLESS_CNXN_TIMEOUT` Default sessionless connection timeout in ms: 10000 (10s)
`static String`	`ZOOKEEPER_NIO_SHUTDOWN_TIMEOUT` Default worker pool shutdown timeout in ms: 5000 (5s)

Fields inherited from class org.apache.zookeeper.server.ServerCnxnFactory
cnxns, login, saslServerCallbackHandler, secure, zkServer, ZOOKEEPER_SERVER_CNXN_FACTORY

Constructor Summary

Constructors
Constructor and Description
`NIOServerCnxnFactory()` Construct a new server connection factory which will accept an unlimited number of concurrent connections from each client (up to the file descriptor limits of the operating system).

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addSession(long sessionId, NIOServerCnxn cnxn)`
`void`	`closeAll()` clear all the connections in the selector
`boolean`	`closeSession(long sessionId)`
`void`	`configure(InetSocketAddress addr, int maxcc, boolean secure)`
`protected NIOServerCnxn`	`createConnection(SocketChannel sock, SelectionKey sk, org.apache.zookeeper.server.NIOServerCnxnFactory.SelectorThread selectorThread)`
`void`	`dumpConnections(PrintWriter pwriter)`
`Iterable<Map<String,Object>>`	`getAllConnectionInfo(boolean brief)`
`Iterable<ServerCnxn>`	`getConnections()`
`static ByteBuffer`	`getDirectBuffer()`
`InetSocketAddress`	`getLocalAddress()`
`int`	`getLocalPort()`
`int`	`getMaxClientCnxnsPerHost()` Maximum number of connections allowed from particular host (ip)
`void`	`join()`
`void`	`reconfigure(InetSocketAddress addr)`
`boolean`	`removeCnxn(NIOServerCnxn cnxn)` De-registers the connection from the various mappings maintained by the factory.
`void`	`resetAllConnectionStats()`
`void`	`setMaxClientCnxnsPerHost(int max)` Maximum number of connections allowed from particular host (ip)
`void`	`shutdown()`
`void`	`start()`
`void`	`startup(ZooKeeperServer zks, boolean startServer)`
`void`	`stop()`
`void`	`touchCnxn(NIOServerCnxn cnxn)` Add or update cnxn in our cnxnExpiryQueue

Methods inherited from class org.apache.zookeeper.server.ServerCnxnFactory
configure, configureSaslLogin, createFactory, createFactory, createFactory, getNumAliveConnections, getZooKeeperServer, isSecure, registerConnection, setZooKeeperServer, startup, unregisterConnection

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - ZOOKEEPER_NIO_SESSIONLESS_CNXN_TIMEOUT
```
public static final String ZOOKEEPER_NIO_SESSIONLESS_CNXN_TIMEOUT
```
    Default sessionless connection timeout in ms: 10000 (10s)
    
    See Also:
    
    Constant Field Values
  - ZOOKEEPER_NIO_NUM_SELECTOR_THREADS
```
public static final String ZOOKEEPER_NIO_NUM_SELECTOR_THREADS
```
    With 500 connections to an observer with watchers firing on each, is unable to exceed 1GigE rates with only 1 selector. Defaults to using 2 selector threads with 8 cores and 4 with 32 cores. Expressed as sqrt(numCores/2). Must have at least 1 selector thread.
    
    See Also:
    
    Constant Field Values
  - ZOOKEEPER_NIO_NUM_WORKER_THREADS
```
public static final String ZOOKEEPER_NIO_NUM_WORKER_THREADS
```
    Default: 2 * numCores
    
    See Also:
    
    Constant Field Values
  - ZOOKEEPER_NIO_DIRECT_BUFFER_BYTES
```
public static final String ZOOKEEPER_NIO_DIRECT_BUFFER_BYTES
```
    Default: 64kB
    
    See Also:
    
    Constant Field Values
  - ZOOKEEPER_NIO_SHUTDOWN_TIMEOUT
```
public static final String ZOOKEEPER_NIO_SHUTDOWN_TIMEOUT
```
    Default worker pool shutdown timeout in ms: 5000 (5s)
    
    See Also:
    
    Constant Field Values
  - maxClientCnxns
```
protected int maxClientCnxns
```
  - workerPool
```
protected WorkerService workerPool
```
- Constructor Detail
  - NIOServerCnxnFactory
```
public NIOServerCnxnFactory()
```
    Construct a new server connection factory which will accept an unlimited number of concurrent connections from each client (up to the file descriptor limits of the operating system). startup(zks) must be called subsequently.
- Method Detail
  - getDirectBuffer
```
public static ByteBuffer getDirectBuffer()
```
  - configure
```
public void configure(InetSocketAddress addr,
                      int maxcc,
                      boolean secure)
               throws IOException
```
    Specified by:
    
    configure in class ServerCnxnFactory
    
    Throws:
    
    IOException
  - reconfigure
```
public void reconfigure(InetSocketAddress addr)
```
    Specified by:
    
    reconfigure in class ServerCnxnFactory
  - getMaxClientCnxnsPerHost
```
public int getMaxClientCnxnsPerHost()
```
    Maximum number of connections allowed from particular host (ip)
    
    Specified by:
    
    getMaxClientCnxnsPerHost in class ServerCnxnFactory
  - setMaxClientCnxnsPerHost
```
public void setMaxClientCnxnsPerHost(int max)
```
    Maximum number of connections allowed from particular host (ip)
    
    Specified by:
    
    setMaxClientCnxnsPerHost in class ServerCnxnFactory
  - start
```
public void start()
```
    Specified by:
    
    start in class ServerCnxnFactory
  - startup
```
public void startup(ZooKeeperServer zks,
                    boolean startServer)
             throws IOException,
                    InterruptedException
```
    Specified by:
    
    startup in class ServerCnxnFactory
    
    Throws:
    
    IOException
    
    InterruptedException
  - getLocalAddress
```
public InetSocketAddress getLocalAddress()
```
    Specified by:
    
    getLocalAddress in class ServerCnxnFactory
  - getLocalPort
```
public int getLocalPort()
```
    Specified by:
    
    getLocalPort in class ServerCnxnFactory
  - removeCnxn
```
public boolean removeCnxn(NIOServerCnxn cnxn)
```
    De-registers the connection from the various mappings maintained by the factory.
  - touchCnxn
```
public void touchCnxn(NIOServerCnxn cnxn)
```
    Add or update cnxn in our cnxnExpiryQueue
    
    Parameters:
    
    cnxn -
  - createConnection
```
protected NIOServerCnxn createConnection(SocketChannel sock,
                                         SelectionKey sk,
                                         org.apache.zookeeper.server.NIOServerCnxnFactory.SelectorThread selectorThread)
                                  throws IOException
```
    Throws:
    
    IOException
  - closeAll
```
public void closeAll()
```
    clear all the connections in the selector
    
    Specified by:
    
    closeAll in class ServerCnxnFactory
  - stop
```
public void stop()
```
  - shutdown
```
public void shutdown()
```
    Specified by:
    
    shutdown in class ServerCnxnFactory
  - addSession
```
public void addSession(long sessionId,
                       NIOServerCnxn cnxn)
```
  - closeSession
```
public boolean closeSession(long sessionId)
```
    Specified by:
    
    closeSession in class ServerCnxnFactory
    
    Returns:
    
    true if the cnxn that contains the sessionId exists in this ServerCnxnFactory and it's closed. Otherwise false.
  - join
```
public void join()
          throws InterruptedException
```
    Specified by:
    
    join in class ServerCnxnFactory
    
    Throws:
    
    InterruptedException
  - getConnections
```
public Iterable<ServerCnxn> getConnections()
```
    Specified by:
    
    getConnections in class ServerCnxnFactory
  - dumpConnections
```
public void dumpConnections(PrintWriter pwriter)
```
  - resetAllConnectionStats
```
public void resetAllConnectionStats()
```
    Specified by:
    
    resetAllConnectionStats in class ServerCnxnFactory
  - getAllConnectionInfo
```
public Iterable<Map<String,Object>> getAllConnectionInfo(boolean brief)
```
    Specified by:
    
    getAllConnectionInfo in class ServerCnxnFactory

Class NIOServerCnxnFactory

Field Summary

Fields inherited from class org.apache.zookeeper.server.ServerCnxnFactory

Constructor Summary

Method Summary

Methods inherited from class org.apache.zookeeper.server.ServerCnxnFactory

Methods inherited from class java.lang.Object

Field Detail

ZOOKEEPER_NIO_SESSIONLESS_CNXN_TIMEOUT

ZOOKEEPER_NIO_NUM_SELECTOR_THREADS

ZOOKEEPER_NIO_NUM_WORKER_THREADS

ZOOKEEPER_NIO_DIRECT_BUFFER_BYTES

ZOOKEEPER_NIO_SHUTDOWN_TIMEOUT

maxClientCnxns

workerPool

Constructor Detail

NIOServerCnxnFactory

Method Detail

getDirectBuffer

configure

reconfigure

getMaxClientCnxnsPerHost

setMaxClientCnxnsPerHost

start

startup

getLocalAddress

getLocalPort

removeCnxn

touchCnxn

createConnection

closeAll

stop

shutdown

addSession

closeSession

join

getConnections

dumpConnections

resetAllConnectionStats

getAllConnectionInfo