org.apache.zookeeper.client

Class StaticHostProvider

java.lang.Object

org.apache.zookeeper.client.StaticHostProvider

All Implemented Interfaces:

HostProvider

@InterfaceAudience.Public
public final class StaticHostProvider
extends java.lang.Object
implements HostProvider

Most simple HostProvider, resolves on every next() call. Please be aware that although this class doesn't do any DNS caching, there're multiple levels of caching already present across the stack like in JVM, OS level, hardware, etc. The best we could do here is to get the most recent address from the underlying system which is considered up-to-date.

Constructor Summary

Constructors

Constructor and Description
StaticHostProvider(java.util.Collection<java.net.InetSocketAddress> serverAddresses) Constructs a SimpleHostSet.
StaticHostProvider(java.util.Collection<java.net.InetSocketAddress> serverAddresses, org.apache.zookeeper.client.StaticHostProvider.Resolver resolver) Introduced for testing purposes.

Method Summary

Modifier and Type	Method and Description
java.net.InetSocketAddress	next(long spinDelay) The next host to try to connect to.
void	onConnected() Notify the HostProvider of a successful connection.
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

StaticHostProvider

public StaticHostProvider(java.util.Collection<java.net.InetSocketAddress> serverAddresses)

Constructs a SimpleHostSet.

Parameters:

serverAddresses - possibly unresolved ZooKeeper server addresses

Throws:

java.lang.IllegalArgumentException - if serverAddresses is empty or resolves to an empty list

StaticHostProvider

public StaticHostProvider(java.util.Collection<java.net.InetSocketAddress> serverAddresses,
                          org.apache.zookeeper.client.StaticHostProvider.Resolver resolver)

Introduced for testing purposes. getAllByName() is a static method of InetAddress, therefore cannot be easily mocked. By abstraction of Resolver interface we can easily inject a mocked implementation in tests.

Parameters:

serverAddresses - possibly unresolved ZooKeeper server addresses

resolver - custom resolver implementation

Throws:

java.lang.IllegalArgumentException - if serverAddresses is empty or resolves to an empty list

Method Detail

size

public int size()

Specified by:

size in interface HostProvider

next

public java.net.InetSocketAddress next(long spinDelay)

Description copied from interface: HostProvider

The next host to try to connect to. For a spinDelay of 0 there should be no wait.

Specified by:

next in interface HostProvider

Parameters:

spinDelay - Milliseconds to wait if all hosts have been tried once.

Returns:

The next host to try to connect to with resolved address. If the host is not resolvable, the unresolved address will be returned.

onConnected

public void onConnected()

Description copied from interface: HostProvider

Notify the HostProvider of a successful connection. The HostProvider may use this notification to reset it's inner state.

Specified by:

onConnected in interface HostProvider