org.talend.esb.servicelocator.client.internal
Class ServiceLocatorImpl

java.lang.Object
  org.talend.esb.servicelocator.client.internal.ServiceLocatorImpl

All Implemented Interfaces:

ServiceLocator

public class ServiceLocatorImpl
extends Object
implements ServiceLocator

This is the entry point for clients of the Service Locator. To access the Service Locator clients have to first connect to the Service Locator to get a session assigned. Once the connection is established the client will periodically send heart beats to the server to keep the session alive.

The Service Locator provides the following operations.

• An endpoint for a specific service can be registered.
• All endpoints for a specific service that were registered before by other clients can be looked up.

Nested Class Summary

class

ServiceLocatorImpl.WatcherImpl

Nested classes/interfaces inherited from interface org.talend.esb.servicelocator.client.ServiceLocator

ServiceLocator.PostConnectAction

Field Summary

static ServiceLocator.PostConnectAction	DO_NOTHING_ACTION
static byte[]	EMPTY_CONTENT
static String	LIVE
static NodePath	LOCATOR_ROOT_PATH

Constructor Summary

ServiceLocatorImpl()

Method Summary

void	connect() Establish a connection to the Service Locator.
protected org.apache.zookeeper.ZooKeeper	createZooKeeper(CountDownLatch connectionLatch)
void	disconnect() Disconnects from a Service Locator server.
SLEndpoint	getEndpoint(QName serviceName, String endpoint)
List<String>	getEndpointNames(QName serviceName) For the given service return all endpoints that currently registered at the Service Locator Service.
List<SLEndpoint>	getEndpoints(QName serviceName)
List<QName>	getServices() Return all services for which endpoints are registered at the Service Locator Service.
List<String>	lookup(QName serviceName) For the given service return all endpoints that currently registered at the Service Locator Service.
List<String>	lookup(QName serviceName, SLPropertiesMatcher matcher)
void	register(EndpointProvider epProvider)
void	register(QName serviceName, String endpoint) For a given service register the endpoint of a concrete provider of this service.
void	register(QName serviceName, String endpoint, SLProperties properties)
void	removeEndpoint(QName serviceName, String endpoint)
void	setConnectionTimeout(int timeout) Specify the time this client waits for a connection to get established.
void	setLocatorEndpoints(String endpoints) Specify the endpoints of all the instances belonging to the service locator ensemble this object might potentially be talking to when connecting.
void	setPostConnectAction(ServiceLocator.PostConnectAction postConnectAction)
void	setSessionTimeout(int timeout) Specify the time out of the session established at the server.
void	unregister(EndpointProvider epProvider)
void	unregister(QName serviceName, String endpoint) For a given service unregister a previously registered endpoint.

Methods inherited from class java.lang.Object

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

Field Detail

LOCATOR_ROOT_PATH

public static final NodePath LOCATOR_ROOT_PATH

LIVE

public static final String LIVE

See Also:

Constant Field Values

EMPTY_CONTENT

public static final byte[] EMPTY_CONTENT

DO_NOTHING_ACTION

public static final ServiceLocator.PostConnectAction DO_NOTHING_ACTION

Constructor Detail

ServiceLocatorImpl

public ServiceLocatorImpl()

Method Detail

connect

public void connect()
             throws InterruptedException,
                    ServiceLocatorException

Establish a connection to the Service Locator. After successful connection the specified ServiceLocator.PostConnectAction is run. If the session to the server expires because the server could not be reached within the specified time, a reconnect is automatically executed as soon as the server can be reached again. Because after a session time out all registered endpoints are removed it is important to specify a ServiceLocator.PostConnectAction that re-registers all endpoints.

Specified by:

connect in interface ServiceLocator

Throws:

InterruptedException - the current Thread was interrupted when waiting for a successful connection to the ServiceLocator

ServiceLocatorException - the connect operation failed

disconnect

public void disconnect()
                throws InterruptedException,
                       ServiceLocatorException

Disconnects from a Service Locator server. All endpoints that were registered before are removed from the server. To be able to communicate with a Service Locator server again the client has to connect again.

Specified by:

disconnect in interface ServiceLocator

Throws:

InterruptedException - the current Thread was interrupted when waiting for the disconnect to happen

ServiceLocatorException

register

public void register(QName serviceName,
                     String endpoint)
              throws ServiceLocatorException,
                     InterruptedException

For a given service register the endpoint of a concrete provider of this service. If the client is destroyed, disconnected, or fails to successfully send the heartbeat for a period of time defined by the session timeout parameter the endpoint is removed from the Service Locator. To ensure that all available endpoints are re-registered when the client reconnects after a session expired a ServiceLocator.PostConnectAction should be set that registers all endpoints.

Specified by:

register in interface ServiceLocator

Parameters:

serviceName - the name of the service the endpoint is registered for, must not be null

endpoint - the endpoint to register, must not be null

Throws:

ServiceLocatorException - the server returned an error

InterruptedException - the current Thread was interrupted when waiting for a response of the ServiceLocator

register

public void register(QName serviceName,
                     String endpoint,
                     SLProperties properties)
              throws ServiceLocatorException,
                     InterruptedException

Specified by:

register in interface ServiceLocator

Throws:

ServiceLocatorException

InterruptedException

register

public void register(EndpointProvider epProvider)
              throws ServiceLocatorException,
                     InterruptedException

Specified by:

register in interface ServiceLocator

Throws:

ServiceLocatorException

InterruptedException

unregister

public void unregister(EndpointProvider epProvider)
                throws ServiceLocatorException,
                       InterruptedException

Specified by:

unregister in interface ServiceLocator

Throws:

ServiceLocatorException

InterruptedException

unregister

public void unregister(QName serviceName,
                       String endpoint)
                throws ServiceLocatorException,
                       InterruptedException

For a given service unregister a previously registered endpoint.

Specified by:

unregister in interface ServiceLocator

Parameters:

serviceName - the name of the service the endpoint is unregistered for, must not be null

endpoint - the endpoint to unregister, must not be null

Throws:

ServiceLocatorException - the server returned an error

InterruptedException - the current Thread was interrupted when waiting for a response of the ServiceLocator

removeEndpoint

public void removeEndpoint(QName serviceName,
                           String endpoint)
                    throws ServiceLocatorException,
                           InterruptedException

Specified by:

removeEndpoint in interface ServiceLocator

Throws:

ServiceLocatorException

InterruptedException

getServices

public List<QName> getServices()
                        throws InterruptedException,
                               ServiceLocatorException

Return all services for which endpoints are registered at the Service Locator Service.

Specified by:

getServices in interface ServiceLocator

Returns:

a possibly empty list of services

Throws:

InterruptedException - the current Thread was interrupted when waiting for a response of the ServiceLocator

ServiceLocatorException - the server returned an error

getEndpoints

public List<SLEndpoint> getEndpoints(QName serviceName)
                              throws ServiceLocatorException,
                                     InterruptedException

Specified by:

getEndpoints in interface ServiceLocator

Throws:

ServiceLocatorException

InterruptedException

getEndpoint

public SLEndpoint getEndpoint(QName serviceName,
                              String endpoint)
                       throws ServiceLocatorException,
                              InterruptedException

Specified by:

getEndpoint in interface ServiceLocator

Throws:

ServiceLocatorException

InterruptedException

getEndpointNames

public List<String> getEndpointNames(QName serviceName)
                              throws ServiceLocatorException,
                                     InterruptedException

For the given service return all endpoints that currently registered at the Service Locator Service.

Specified by:

getEndpointNames in interface ServiceLocator

Parameters:

serviceName - the name of the service for which to get the endpoints, must not be null

Returns:

a possibly empty list of endpoints

Throws:

ServiceLocatorException - the server returned an error

InterruptedException - the current Thread was interrupted when waiting for a response of the ServiceLocator

lookup

public List<String> lookup(QName serviceName)
                    throws ServiceLocatorException,
                           InterruptedException

For the given service return all endpoints that currently registered at the Service Locator Service.

Specified by:

lookup in interface ServiceLocator

Parameters:

serviceName - the name of the service for which to get the endpoints, must not be null

Returns:

a possibly empty list of endpoints

Throws:

ServiceLocatorException - the server returned an error

InterruptedException - the current Thread was interrupted when waiting for a response of the ServiceLocator

lookup

public List<String> lookup(QName serviceName,
                           SLPropertiesMatcher matcher)
                    throws ServiceLocatorException,
                           InterruptedException

Specified by:

lookup in interface ServiceLocator

Throws:

ServiceLocatorException

InterruptedException

setLocatorEndpoints

public void setLocatorEndpoints(String endpoints)

Specify the endpoints of all the instances belonging to the service locator ensemble this object might potentially be talking to when connecting. The object will one by one pick an endpoint (the order is non-deterministic) to connect to the service locator until a connection is established.

Parameters:

endpoints - comma separated list of endpoints,each corresponding to a service locator instance. Each endpoint is specified as a host:port pair. At least one endpoint must be specified. Valid exmaples are: "127.0.0.1:2181" or "sl1.example.com:3210, sl2.example.com:3210, sl3.example.com:3210"

setSessionTimeout

public void setSessionTimeout(int timeout)

Specify the time out of the session established at the server. The session is kept alive by requests sent by this client object. If the session is idle for a period of time that would timeout the session, the client will send a PING request to keep the session alive.

Parameters:

sessionTimeout - timeout in milliseconds, must be greater than zero and less than 60000.

setConnectionTimeout

public void setConnectionTimeout(int timeout)

Specify the time this client waits for a connection to get established.

Parameters:

connectionTimeout - timeout in milliseconds, must be greater than zero

setPostConnectAction

public void setPostConnectAction(ServiceLocator.PostConnectAction postConnectAction)

Specified by:

setPostConnectAction in interface ServiceLocator

createZooKeeper

protected org.apache.zookeeper.ZooKeeper createZooKeeper(CountDownLatch connectionLatch)
                                                  throws ServiceLocatorException

Throws:

ServiceLocatorException