org.apache.river.start

Class SharedGroupImpl

java.lang.Object

org.apache.river.start.SharedGroupImpl

All Implemented Interfaces:

Remote, ProxyAccessor, ServerProxyTrust, Startable, SharedGroup, SharedGroupBackEnd

public class SharedGroupImpl
extends Object
implements Remote, SharedGroupBackEnd, ServerProxyTrust, ProxyAccessor, Startable

The provided implementation of the SharedGroup service. The following items are discussed below:

• Configuring SharedGroupImpl
• Logging

Configuring SharedGroupImpl

This implementation of SharedGroupImpl supports the following configuration entries, with component org.apache.river.start:

•	activationIdPreparer
	Type:	ProxyPreparer
	Default:	new BasicProxyPreparer()
	Description:	The proxy preparer for the service's activation ID. The value should not be null. The service starter calls the activate method to activate the service.

•	activationSystemPreparer
	Type:	ProxyPreparer
	Default:	new BasicProxyPreparer()
	Description:	The proxy preparer for the proxy for the activation system. The value should not be null. This entry is obtained at service start and restart. The service calls the unregisterGroup method on the ActivationSystem upon service destruction.

•	exporter
	Type:	Exporter
	Default:	new ActivationExporter( activationID, new BasicJeriExporter( TcpServerEndpoint.getInstance(0), new BasicILFactory(), false, true))
	Description:	The object to use for exporting the service. The value should not be null. The call to getEntry will supply the activation ID in the data argument. This entry is obtained at service start and restart.

•	loginContext
	Type:	LoginContext
	Default:	null
	Description:	If not null, specifies the JAAS login context to use for performing a JAAS login and supplying the Subject to use when running the service. If null, no JAAS login is performed. This entry is obtained at service start and restart.

Loggers and Logging Levels

The SharedGroupImpl service implementation uses the Logger, named org.apache.river.sharedGroup. The following table describes the type of information logged as well as the levels of information logged.

org.apache.river.start.sharedGroup

Level	Description
FINE	for low level service operation tracing
FINER	for lower level service operation tracing
FINEST	for lowest level service operation tracing

Author:

Sun Microsystems, Inc.

Field Summary

Fields

Modifier and Type	Field and Description
protected Exporter	exporter The exporter for exporting and unexporting

Method Summary

Modifier and Type	Method and Description
void	destroyVM() Cause the hosting VM to exit.
Object	getProxy() Returns a proxy object for this remote object.
TrustVerifier	getProxyVerifier() Returns a TrustVerifier that can be used to verify that a proxy can be trusted as a proxy for the service; that is, the isTrustedObject method of the returned verifier can be called with a candidate proxy.
void	start() Called after construction, this method enables objects to delay starting threads or exporting until after construction is complete, to allow safe publication of the service in accordance with the JMM.

Methods inherited from class java.lang.Object

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

Field Detail

exporter

protected final Exporter exporter

The exporter for exporting and unexporting

Method Detail

start

public final void start()
                 throws ExportException

Description copied from interface: Startable

Called after construction, this method enables objects to delay starting threads or exporting until after construction is complete, to allow safe publication of the service in accordance with the JMM.

In addition to starting threads after construction, it also allows objects to avoid throwing an exception during construction to avoid finalizer attacks.

The implementation is required to ensure start() is idempotent (only executed once, additional invocations must return immediately).

Specified by:

start in interface Startable

Throws:

ExportException

destroyVM

public void destroyVM()
               throws RemoteException,
                      ActivationException

Description copied from interface: SharedGroup

Cause the hosting VM to exit. This method should (in effect) spawn a separate thread to do the actual work asynchronously, and make a reasonable attempt to let this remote call return successfully. As such, a successful return from this method does not mean that the VM has been destroyed. Although the service should make a reasonable attempt to let this remote call return successfully, the service must not wait indefinitely for other (in-progress and subsequent) remote calls to finish before proceeding to destroy its hosting VM. Once this method has been called, the service can, but need not, reject all other (in-progress and subsequent) remote calls to the service.

Specified by:

destroyVM in interface SharedGroup

Throws:

RemoteException - if there was a problem communicating with the shared group object

ActivationException - if there was a problem creating an activatable shared group instance

getProxy

public Object getProxy()

Description copied from interface: ProxyAccessor

Returns a proxy object for this remote object. If this remote object is not exported (and hence, no proxy is available), then null is returned.

Specified by:

getProxy in interface ProxyAccessor

Returns:

a proxy, or null

getProxyVerifier

public TrustVerifier getProxyVerifier()

Description copied from interface: ServerProxyTrust

Returns a TrustVerifier that can be used to verify that a proxy can be trusted as a proxy for the service; that is, the isTrustedObject method of the returned verifier can be called with a candidate proxy. The verifier should be able to verify all proxies for the service, including proxies for resources (such as leases and registrations).

Specified by:

getProxyVerifier in interface ServerProxyTrust

Returns:

a TrustVerifier that can be used to verify that a proxy can be trusted as a proxy for the service