Package org.apache.curator.connection

Class StandardConnectionHandlingPolicy

java.lang.Object

org.apache.curator.connection.StandardConnectionHandlingPolicy

All Implemented Interfaces:

ConnectionHandlingPolicy

public class StandardConnectionHandlingPolicy
extends java.lang.Object
implements ConnectionHandlingPolicy

Curator's standard connection handling since 3.0.0

Since:

3.0.0

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.curator.connection.ConnectionHandlingPolicy

ConnectionHandlingPolicy.CheckTimeoutsResult

Constructor Summary

Constructors

Constructor	Description
StandardConnectionHandlingPolicy()
StandardConnectionHandlingPolicy(int expirationPercent)

Method Summary

Modifier and Type	Method	Description
<T> T	callWithRetry(CuratorZookeeperClient client, java.util.concurrent.Callable<T> proc)	Called by RetryLoop.callWithRetry(CuratorZookeeperClient, Callable) to do the work of retrying
ConnectionHandlingPolicy.CheckTimeoutsResult	checkTimeouts(java.util.concurrent.Callable<java.lang.String> hasNewConnectionString, long connectionStartMs, int sessionTimeoutMs, int connectionTimeoutMs)	Check timeouts.
int	getSimulatedSessionExpirationPercent()	Prior to 3.0.0, Curator did not try to manage session expiration other than the functionality provided by ZooKeeper itself.

Methods inherited from class java.lang.Object

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

Constructor Detail

StandardConnectionHandlingPolicy

public StandardConnectionHandlingPolicy()

StandardConnectionHandlingPolicy

public StandardConnectionHandlingPolicy(int expirationPercent)

Method Detail

getSimulatedSessionExpirationPercent

public int getSimulatedSessionExpirationPercent()

Description copied from interface: ConnectionHandlingPolicy

Prior to 3.0.0, Curator did not try to manage session expiration other than the functionality provided by ZooKeeper itself. Starting with 3.0.0, Curator has the option of attempting to monitor session expiration above what is provided by ZooKeeper. The percentage returned by this method determines how and if Curator will check for session expiration.

If this method returns 0, Curator does not do any additional checking for session expiration.

If a positive number is returned, Curator will check for session expiration as follows: when ZooKeeper sends a Disconnect event, Curator will start a timer. If re-connection is not achieved before the elapsed time exceeds the negotiated session time multiplied by the session expiration percent, Curator will simulate a session expiration. Due to timing/network issues, it is not possible for a client to match the server's session timeout with complete accuracy. Thus, the need for a session expiration percentage.

Specified by:

getSimulatedSessionExpirationPercent in interface ConnectionHandlingPolicy

Returns:

a percentage from 0 to 100 (0 implied no extra session checking)

callWithRetry

public <T> T callWithRetry(CuratorZookeeperClient client,
                           java.util.concurrent.Callable<T> proc)
                    throws java.lang.Exception

Description copied from interface: ConnectionHandlingPolicy

Called by RetryLoop.callWithRetry(CuratorZookeeperClient, Callable) to do the work of retrying

Specified by:

callWithRetry in interface ConnectionHandlingPolicy

Parameters:

client - client

proc - the procedure to retry

Returns:

result

Throws:

java.lang.Exception - errors

checkTimeouts

public ConnectionHandlingPolicy.CheckTimeoutsResult checkTimeouts(java.util.concurrent.Callable<java.lang.String> hasNewConnectionString,
                                                                  long connectionStartMs,
                                                                  int sessionTimeoutMs,
                                                                  int connectionTimeoutMs)
                                                           throws java.lang.Exception

Description copied from interface: ConnectionHandlingPolicy

Check timeouts. NOTE: this method is only called when an attempt to access to the ZooKeeper instances is made and the connection has not completed.

Specified by:

checkTimeouts in interface ConnectionHandlingPolicy

Parameters:

hasNewConnectionString - proc to call to check if there is a new connection string. Important: the internal state is cleared after this is called so you MUST handle the new connection string if non null is returned

connectionStartMs - the epoch/ms time that the connection was first initiated

sessionTimeoutMs - the configured/negotiated session timeout in milliseconds

connectionTimeoutMs - the configured connection timeout in milliseconds

Returns:

result

Throws:

java.lang.Exception - errors