com.sleepycat.je.rep.utilint

Class ServiceDispatcher

java.lang.Object

java.lang.Thread

com.sleepycat.je.utilint.StoppableThread

com.sleepycat.je.rep.utilint.ServiceDispatcher

All Implemented Interfaces:

ExceptionListenerUser, java.lang.Runnable

public class ServiceDispatcher
extends StoppableThread

ServiceDispatcher listens on a specific socket for service requests and dispatches control to the service that is being requested. A service request message has the format: Service: The format of the message is binary, with all text being encoded in ascii. Upon receipt of service request message, the new SocketChannel is queued for processing by the service in the Queue associated with the service. The SocketChannel is the responsibility of the service after this point. It can configure the channel to best suit the requirements of the specific service. The dispatcher returns a single byte to indicate success or failure. The byte value encodes a ServiceDispatcher.Response enumerator.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ServiceDispatcher.ExecutingRunnable
static class	ServiceDispatcher.ExecutingService A service that is run immediately in a thread allocated to it.
class	ServiceDispatcher.LazyQueuingService A queuing service that starts the thread that services the requests lazily, upon first request and terminates the thread when the service is unregistered.
class	ServiceDispatcher.QueuingService A service where requests are simply added to the supplied queue.
static class	ServiceDispatcher.Response The response to a service request.
static class	ServiceDispatcher.ServiceConnectFailedException

Nested classes/interfaces inherited from class java.lang.Thread

java.lang.Thread.State, java.lang.Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class com.sleepycat.je.utilint.StoppableThread

envImpl

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor and Description
ServiceDispatcher(java.net.InetSocketAddress socketAddress) Convenience overloading for when the dispatcher is created without a replicated environment, e.g.
ServiceDispatcher(java.net.InetSocketAddress socketAddress, RepImpl repImpl) Create a ServiceDispatcher listening on a specific socket for service requests.

Method Summary

Methods

Modifier and Type	Method and Description
void	cancel(java.lang.String serviceName) Cancels the registration of a service.
static void	doServiceHandshake(java.nio.channels.SocketChannel channel, java.lang.String serviceName) A variation on the method above.
protected java.util.logging.Logger	getLogger()
static java.io.OutputStream	getServiceOutputStream(java.net.Socket socket, java.lang.String serviceName) Used by the client to establish an output stream for the service on the socket.
java.net.InetSocketAddress	getSocketAddress() Returns the socket associated with the dispatcher
protected int	initiateSoftShutdown() Threads that use shutdownThread() must define this method.
boolean	isRegistered(java.lang.String serviceName)
void	preShutdown() Stop accepting new connections, while the individual services quiesce and shut themselves down.
void	register(com.sleepycat.je.rep.utilint.ServiceDispatcher.Service service)
void	register(java.lang.String serviceName, java.util.concurrent.BlockingQueue<java.nio.channels.SocketChannel> serviceQueue) Registers a service queue with the ServiceDispatcher.
void	run() The central run method.
void	setSimulateIOException(java.lang.String serviceName, boolean simulateException)
void	shutdown() Shuts down the dispatcher, so that it's no longer listening for service requests.
java.nio.channels.SocketChannel	takeChannel(java.lang.String serviceName, boolean blocking, int soTimeout) Returns the next socketChannel created in response to a request for the service.

Methods inherited from class com.sleepycat.je.utilint.StoppableThread

cleanup, getSavedShutdownException, getTotalCpuTime, getTotalUserTime, isShutdown, saveShutdownException, setExceptionListener, shutdownDone, shutdownThread

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Constructor Detail

ServiceDispatcher

public ServiceDispatcher(java.net.InetSocketAddress socketAddress,
                 RepImpl repImpl)
                  throws java.io.IOException

Create a ServiceDispatcher listening on a specific socket for service requests. This service dispatcher has been created on behalf of a replicated environment, and the node will be informed of any unexpected failures seen by the dispatcher.

Parameters:

socketAddress - the socket on which it listens for service requests

Throws:

java.io.IOException - if the socket could not be bound.

ServiceDispatcher

public ServiceDispatcher(java.net.InetSocketAddress socketAddress)
                  throws java.io.IOException

Convenience overloading for when the dispatcher is created without a replicated environment, e.g. when used by the Monitor, and in unit test situations.

Throws:

java.io.IOException

See Also:

ServiceDispatcher(InetSocketAddress, RepImpl)

Method Detail

preShutdown

public void preShutdown()

Stop accepting new connections, while the individual services quiesce and shut themselves down.

shutdown

public void shutdown()

Shuts down the dispatcher, so that it's no longer listening for service requests. The port is freed up upon return and the thread used to listen on the port is shutdown.

initiateSoftShutdown

protected int initiateSoftShutdown()

Description copied from class: StoppableThread

Threads that use shutdownThread() must define this method. It's invoked by shutdownThread as an attempt at a soft shutdown. This method makes provisions for this thread to exit on its own. The technique used to make the thread exit can vary based upon the nature of the service being provided by the thread. For example, the thread may be known to poll some shutdown flag on a periodic basis, or it may detect that a channel that it waits on has been closed by this method.

Overrides:

initiateSoftShutdown in class StoppableThread

Returns:

the amount of time in ms that the shutdownThread method will wait for the thread to exit. A -ve value means that the method will not wait. A zero value means it will wait indefinitely.

getLogger

protected java.util.logging.Logger getLogger()

Specified by:

getLogger in class StoppableThread

Returns:

a logger to use when logging uncaught exceptions.

See Also:

StoppableThread.getLogger()

getServiceOutputStream

public static java.io.OutputStream getServiceOutputStream(java.net.Socket socket,
                                          java.lang.String serviceName)
                                                   throws java.io.IOException,
                                                          ServiceDispatcher.ServiceConnectFailedException

Used by the client to establish an output stream for the service on the socket. It sends out the request for the service and interprets the response to determine if it was successful.

Parameters:

socket - the connected socket that will be the basis for the stream

serviceName - the service running on the stream

Returns:

the output stream ready for subsequent output

Throws:

java.io.IOException - if the output stream could not be established

ServiceDispatcher.ServiceConnectFailedException - if the connection could not be made.

doServiceHandshake

public static void doServiceHandshake(java.nio.channels.SocketChannel channel,
                      java.lang.String serviceName)
                               throws java.io.IOException,
                                      ServiceDispatcher.ServiceConnectFailedException

A variation on the method above. It's used by the client to setup a channel for the service. It performs the initial handshake requesting the service and interpreting the response to determine if it was successful.

Parameters:

channel - the channel that is the basis for the service

serviceName - the service running on the channel

Throws:

ServiceDispatcher.ServiceConnectFailedException - if the connection could not be made.

java.io.IOException

takeChannel

public java.nio.channels.SocketChannel takeChannel(java.lang.String serviceName,
                                          boolean blocking,
                                          int soTimeout)
                                            throws java.lang.InterruptedException

Returns the next socketChannel created in response to a request for the service. The socketChannel and the associated socket is configured as requested in the arguments.

Parameters:

serviceName - the service for which the channel must be created.

blocking - true if the channel must be configured to block

soTimeout - the timeout for the underlying socket

Returns:

the configured channel or null if there are no more channels, because the service has been shut down.

Throws:

java.lang.InterruptedException

getSocketAddress

public java.net.InetSocketAddress getSocketAddress()

Returns the socket associated with the dispatcher

register

public void register(java.lang.String serviceName,
            java.util.concurrent.BlockingQueue<java.nio.channels.SocketChannel> serviceQueue)

Registers a service queue with the ServiceDispatcher. Requests for a service result in a new SocketChannel being created on which the service can communicate with the requester of the service.

Parameters:

serviceName - the name of the service being requested

serviceQueue - the queue that will be used to hold channels established for the service.

register

public void register(com.sleepycat.je.rep.utilint.ServiceDispatcher.Service service)

isRegistered

public boolean isRegistered(java.lang.String serviceName)

setSimulateIOException

public void setSimulateIOException(java.lang.String serviceName,
                          boolean simulateException)

cancel

public void cancel(java.lang.String serviceName)

Cancels the registration of a service. Subsequent attempts to access the service will be ignored and the channel will be closed and will not be queued.

Parameters:

serviceName - the name of the service being cancelled

run

public void run()

The central run method. It dispatches to the "accept" and "read" event processing methods. Upon a completed read, it verifies the validity of the service name and queues the channel for subsequent consumption by the service.

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class java.lang.Thread