Package org.apache.zookeeper.common

Class NettyUtils

java.lang.Object

org.apache.zookeeper.common.NettyUtils

public class NettyUtils
extends Object

Helper methods for netty code.

Field Summary

Fields

Modifier and Type	Field	Description
static String	THREAD_POOL_NAME_PREFIX

Constructor Summary

Constructors

Constructor	Description
NettyUtils()

Method Summary

Modifier and Type	Method	Description
static int	getClientReachableLocalInetAddressCount()	Attempts to detect and return the number of local network addresses that could be used by a client to reach this server.
static io.netty.channel.EventLoopGroup	newNioOrEpollEventLoopGroup()	If Epoll.isAvailable() == true, returns a new EpollEventLoopGroup, otherwise returns a new NioEventLoopGroup.
static io.netty.channel.EventLoopGroup	newNioOrEpollEventLoopGroup(int nThreads)	If Epoll.isAvailable() == true, returns a new EpollEventLoopGroup, otherwise returns a new NioEventLoopGroup.
static Class<? extends io.netty.channel.socket.ServerSocketChannel>	nioOrEpollServerSocketChannel()	If Epoll.isAvailable() == true, returns EpollServerSocketChannel, otherwise returns NioServerSocketChannel.
static Class<? extends io.netty.channel.socket.SocketChannel>	nioOrEpollSocketChannel()	If Epoll.isAvailable() == true, returns EpollSocketChannel, otherwise returns NioSocketChannel.

Methods inherited from class java.lang.Object

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

Field Detail

THREAD_POOL_NAME_PREFIX

public static final String THREAD_POOL_NAME_PREFIX

See Also:

Constant Field Values

Constructor Detail

NettyUtils

public NettyUtils()

Method Detail

newNioOrEpollEventLoopGroup

public static io.netty.channel.EventLoopGroup newNioOrEpollEventLoopGroup()

If Epoll.isAvailable() == true, returns a new EpollEventLoopGroup, otherwise returns a new NioEventLoopGroup. Creates the event loop group using the default number of threads.

Returns:

a new EventLoopGroup.

newNioOrEpollEventLoopGroup

public static io.netty.channel.EventLoopGroup newNioOrEpollEventLoopGroup(int nThreads)

If Epoll.isAvailable() == true, returns a new EpollEventLoopGroup, otherwise returns a new NioEventLoopGroup. Creates the event loop group using the specified number of threads instead of the default.

Parameters:

nThreads - see NioEventLoopGroup(int).

Returns:

a new EventLoopGroup.

nioOrEpollSocketChannel

public static Class<? extends io.netty.channel.socket.SocketChannel> nioOrEpollSocketChannel()

If Epoll.isAvailable() == true, returns EpollSocketChannel, otherwise returns NioSocketChannel.

Returns:

a socket channel class.

nioOrEpollServerSocketChannel

public static Class<? extends io.netty.channel.socket.ServerSocketChannel> nioOrEpollServerSocketChannel()

If Epoll.isAvailable() == true, returns EpollServerSocketChannel, otherwise returns NioServerSocketChannel.

Returns:

a server socket channel class.

getClientReachableLocalInetAddressCount

public static int getClientReachableLocalInetAddressCount()

Attempts to detect and return the number of local network addresses that could be used by a client to reach this server. This means we exclude the following address types:

• Multicast addresses. Zookeeper server sockets use TCP, thus cannot bind to a multicast address.
• Link-local addresses. Routers don't forward traffic sent to a link-local address, so any realistic server deployment would not have clients using these.
• Loopback addresses. These are typically only used for testing.

Any remaining addresses are counted, and the total count is returned. This number is used to configure the number of threads for the "boss" event loop group, to make sure we have enough threads for each address in case the server is configured to listen on all available addresses. If listing the network interfaces fails, this method will return 1.

Returns:

the number of client-reachable local network addresses found, or 1 if listing the network interfaces fails.