com.bigdata.service.jini.AbstractServer
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java.lang.Object
public abstract class AbstractServer
Abstract base class for configurable services discoverable using JINI. The
recommended way to start a server is using the ServiceStarter.
However, they may also be started from the command line using main(String[]).
You must specify a policy file granting sufficient permissions for the server
to start.
java -Djava.security.policy=policy.all ....You must specify the JVM property
-Dcom.sun.jini.jeri.tcp.useNIO=true to enable NIO.
Other command line options MAY be recommended depending on the JVM and the
service that you are starting, e.g., -server.
The service may be terminated by terminating the server process.
Termination implies that the server stops execution but that it MAY be
restarted. A shutdown hook is
installed by the server so that you can also stop the server using ^C
(Windows) and kill pid (Un*x). You can record the PID of
the process running the server when you start it under Un*x using a shell
script. Note that if you are starting multiple services at once with the
ServiceStarter then these methods (^C or kill pid) will take
down all servers running in the same VM.
Services may be destroyed using DestroyAdmin, e.g., through
the Jini service browser. Note that all persistent data associated with that
service is also destroyed!
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6380355, which
describes a bug in the service browser that will display a
"NullPointerException" dialog box if you destroy a service which
implements {@link DestroyAdmin} but not {@link JoinAdmin}.,
://java.sun.com/products/jini/2.0/doc/api/com/sun/jini/start/ServiceStarter
.html for documentation on how to use the ServiceStarter.StatusType and link its values to the running state of the
service., add ServiceType with suitable pretty icons.| Nested Class Summary | |
|---|---|
static interface |
AbstractServer.ConfigurationOptions
|
protected class |
AbstractServer.MasterElectionTask
Task runs forever competing to become the master. |
| Field Summary | |
|---|---|
protected net.jini.config.Configuration |
config
The Configuration read based on the args[] provided when the
server is started. |
protected Remote |
impl
The service implementation object. |
protected static org.apache.log4j.Logger |
log
|
protected String |
logicalServiceZPath
The zpath (zookeeper path) to the znode for the logical service of which this service is an instance. |
protected String |
physicalServiceZPath
The path to the ephemeral znode (zookeeper node) for this service instance. |
protected Remote |
proxy
The exported proxy for the service implementation object. |
| Constructor Summary | |
|---|---|
protected |
AbstractServer(String[] args,
com.sun.jini.start.LifeCycle lifeCycle)
Server startup reads Configuration data from the file or URL
named by args and applies any optional overrides, starts the
service, and advertises the service for discovery. |
| Method Summary | |
|---|---|
void |
destroy()
Contract is to shutdown the services and destroy its persistent state. |
protected void |
fatal(String msg,
Throwable t)
This method handles fatal exceptions for the server. |
JiniClient |
getClient()
The object used to connect to and access the other services in the IBigdataFederation. |
protected FileFilter |
getFileFilter()
Method may be overriden to recognize files in the service directory so they may be automatically deleted by destroy() after the
IService.destroy() has been invoked to destroy any files claimed
by the service implementation. |
protected String |
getHostName()
The name of the host on which the server is running. |
protected net.jini.lookup.JoinManager |
getJoinManager()
|
Remote |
getProxy()
The exported proxy for the service implementation object. |
net.jini.core.lookup.ServiceID |
getServiceID()
Return the assigned ServiceID. |
String |
getServiceName()
The configured name for the service a generated service name if no Name was found in the Configuration. |
protected boolean |
isPersistent()
true iff this is a persistent service (one that you can
shutdown and restart). |
boolean |
isShuttingDown()
Return true iff the service is shutting down. |
protected abstract Remote |
newService(Properties properties)
This method is responsible for creating the remote service implementation object. |
void |
notify(net.jini.lease.LeaseRenewalEvent event)
Logs a message. |
protected void |
notifyServiceUUID(net.jini.core.lookup.ServiceID serviceID)
Notify the AbstractService that it's service UUID has been set. |
static net.jini.core.lookup.ServiceID |
readServiceId(File file)
Read and return the ServiceID from an existing local file. |
void |
run()
Run the server (this should be invoked from main. |
void |
runDestroy()
Runs destroy() and logs start and end events. |
void |
serviceIDNotify(net.jini.core.lookup.ServiceID serviceID)
This method is responsible for saving the ServiceID on stable
storage when it is invoked. |
static void |
setSecurityManager()
Conditionally install a suitable security manager if there is none in place. |
void |
shutdownNow(boolean destroy)
Shutdown the server, including the service and any jini processing. |
protected void |
terminate()
Terminates service management threads. |
String |
toString()
Simple representation of state (non-blocking, safe). |
protected boolean |
unexport(boolean force)
Unexports the proxy - this is a NOP if the proxy is
null. |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
| Field Detail |
|---|
protected static final org.apache.log4j.Logger log
protected String logicalServiceZPath
Configuration.
protected String physicalServiceZPath
CreateMode.EPHEMERAL_SEQUENTIAL child of
logicalServiceZPath.
protected net.jini.config.Configuration config
Configuration read based on the args[] provided when the
server is started.
protected Remote impl
protected Remote proxy
| Constructor Detail |
|---|
protected AbstractServer(String[] args,
com.sun.jini.start.LifeCycle lifeCycle)
Configuration data from the file or URL
named by args and applies any optional overrides, starts the
service, and advertises the service for discovery. Aside from the server
class to start, the behavior is more or less entirely parameterized by
the Configuration.
args - Either the command line arguments or the arguments from the
ServiceDescriptor. Either way they identify the jini
Configuration (you may specify either a file or URL)
and optional overrides for that Configuration.lifeCycle - The life cycle object. This is used if the server is started
by the jini ServiceStarter. Otherwise specify a
FakeLifeCycle.NonActivatableServiceDescriptor| Method Detail |
|---|
public final String getServiceName()
Name was found in the Configuration.
Note: Concrete implementations MUST prefer to report this name in the
AbstractService.getServiceName() of their service implementation
class. E.g., DataServer.AdministrableDataService.getServiceName().
protected String getHostName()
public Remote getProxy()
public net.jini.core.lookup.ServiceID getServiceID()
ServiceID. If this is a new service and the
ServiceUUID was not specified in the Configuration then
the ServiceID will be null until it has been
assigned by a ServiceRegistrar.
protected boolean isPersistent()
true iff this is a persistent service (one that you can
shutdown and restart).
MapServer and the
ReduceServer if we keep those classes.protected net.jini.lookup.JoinManager getJoinManager()
public JiniClient getClient()
IBigdataFederation.
public static final void setSecurityManager()
java.rmi.server.codebase property specified for the VM
running the service.
protected void fatal(String msg,
Throwable t)
The default implementation logs the throwable, invokes
#shutdownNow() to terminate any processing and release all
resources, wraps the throwable as a runtime exception and rethrows the
wrapped exception.
This implementation MAY be overridden to invoke System.exit(int)
IFF it is known that the server is being invoked from a command line
context. However in no case should execution be allowed to return to the
caller.
public String toString()
null depending on the server
state.
toString in class Objectprotected boolean unexport(boolean force)
proxy - this is a NOP if the proxy is
null.
force - When true, the object is unexported even if there are pending
or in progress service requests.
Exporter.unexport(boolean)
public static net.jini.core.lookup.ServiceID readServiceId(File file)
throws IOException
ServiceID from an existing local file.
file - The file whose contents are the serialized ServiceID.
ServiceID read from that file.
IOException - if the ServiceID could not be read from the file.public void serviceIDNotify(net.jini.core.lookup.ServiceID serviceID)
ServiceID on stable
storage when it is invoked. It will be invoked iff the ServiceID
was not defined and one was therefore assigned.
serviceIDNotify in interface net.jini.lookup.ServiceIDListenerserviceID - The assigned ServiceID.protected void notifyServiceUUID(net.jini.core.lookup.ServiceID serviceID)
AbstractService that it's service UUID has been set.
public void notify(net.jini.lease.LeaseRenewalEvent event)
ServiceRegistrars then logs an error message.
Note: a service that is no longer registered with any
ServiceRegistrars is no longer discoverable but it remains
accessible to clients which already have its proxy. If a new
ServiceRegistrar accepts registration by the service then it will
become discoverable again as well.
Note: This is only invoked if the automatic lease renewal by the lease manager is denied by the service registrar.
notify in interface net.jini.lease.LeaseListenerpublic void shutdownNow(boolean destroy)
This implementation:
IServiceShutdown.shutdownNow() is invoke if the service
implements IServiceShutdownNonActivatableServiceDescriptorNote: All errors are trapped, logged, and ignored.
Note: Normally, extended shutdown behavior is handled by the service implementation, not the server. However, subclasses MAY extend this method to terminate any additional processing and release any additional resources, taking care to (a) declare the method as synchronized, conditionally halt any asynchonrous processing not already halted, conditionally release any resources not already released, and trap, log, and ignored all errors.
Note: This is run from within the ShutdownThread in response to a
request to destroy the service.
destroy - When true the persistent state associated with
the service is also destroyed.public boolean isShuttingDown()
true iff the service is shutting down.
protected void terminate()
Subclasses which start additional service managment threads SHOULD extend this method to terminate those threads. The implementation should be synchronized, should conditionally terminate each thread, and should trap, log, and ignore all errors.
public void run()
main.
run in interface Runnablepublic final void destroy()
shutdownNow(boolean) with
destroy := true.
protected FileFilter getFileFilter()
destroy() after the
IService.destroy() has been invoked to destroy any files claimed
by the service implementation. The default implementation of this method
does not recognize any files.
public void runDestroy()
destroy() and logs start and end events.
protected abstract Remote newService(Properties properties)
Remote interface. The server will use JERI to create a proxy for
the remote object and configure and manage the protocol for
communications between the client (service proxy) and the remote object
(the service implementation).
Note: You have to implement JoinAdmin in order to show up as an
administerable service (blue folder) in the jini Service Browser.
properties - The contents of the Properties file whose name was
given by the propertyFile value in the
Configuration identified to main by its
command line arguments.
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