/*
* Copyright 2007-2010 Sun Microsystems, Inc.
*
* This file is part of Project Darkstar Server.
*
* Project Darkstar Server is free software: you can redistribute it
* and/or modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation and
* distributed hereunder to you.
*
* Project Darkstar Server is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* --
*/
package com.sun.sgs.impl.service.session;
import com.sun.sgs.app.ClientSession;
import com.sun.sgs.app.ClientSessionListener;
import com.sun.sgs.app.Delivery;
import com.sun.sgs.app.DeliveryNotSupportedException;
import com.sun.sgs.app.ManagedObject;
import com.sun.sgs.app.ManagedObjectRemoval;
import com.sun.sgs.app.ManagedReference;
import com.sun.sgs.app.MessageRejectedException;
import com.sun.sgs.app.NameNotBoundException;
import com.sun.sgs.app.ObjectNotFoundException;
import com.sun.sgs.app.ResourceUnavailableException;
import com.sun.sgs.app.Task;
import com.sun.sgs.app.TransactionException;
import com.sun.sgs.auth.Identity;
import com.sun.sgs.impl.service.session.ClientSessionHandler.DisconnectAction;
import com.sun.sgs.impl.service.session.ClientSessionHandler.MoveAction;
import com.sun.sgs.impl.service.session.ClientSessionHandler.SendMessageAction;
import com.sun.sgs.impl.sharedutil.HexDumper;
import com.sun.sgs.impl.sharedutil.LoggerWrapper;
import com.sun.sgs.impl.util.AbstractKernelRunnable;
import com.sun.sgs.impl.util.IoRunnable;
import static com.sun.sgs.impl.util.AbstractService.isRetryableException;
import com.sun.sgs.impl.util.ManagedQueue;
import com.sun.sgs.service.DataService;
import com.sun.sgs.service.Node;
import com.sun.sgs.service.TaskService;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Implements a client session. The non-static, non-transient fields of an
* instance of this class are the persistent state of a client session and
* are only accessed transactionally.
*/
public class ClientSessionImpl
implements ClientSession, NodeAssignment, Serializable
{
/** The serialVersionUID for this class. */
private static final long serialVersionUID = 1L;
/** The logger name and prefix for the various session keys. */
private static final String PKG_NAME = "com.sun.sgs.impl.service.session.";
/** The session component in a session key. */
private static final String SESSION_COMPONENT = "impl.";
/** The listener component in a session's listener key. */
private static final String LISTENER_COMPONENT = "listener.";
/** The event queue component in a session's event queue key. */
private static final String QUEUE_COMPONENT = "queue.";
/** The node component in a session's node key. */
private static final String NODE_COMPONENT = "node.";
/** The logger for this class. */
private static final LoggerWrapper logger =
new LoggerWrapper(Logger.getLogger(PKG_NAME + "impl"));
/** The local ClientSessionService. */
private transient ClientSessionServiceImpl sessionService;
/** The session ID. */
private transient BigInteger id;
/** The session ID bytes.
* TBD: this should be a transient field.
*/
private final byte[] idBytes;
/** The wrapped client session instance. */
private final ManagedReference<ClientSessionWrapper> wrappedSessionRef;
/** The identity for this session. */
private final Identity identity;
/** The set of delivery requirements for this session. */
private final Set<Delivery> deliveries;
/** The node ID for this session. */
private long nodeId;
/** Indicates whether this session is connected. */
private boolean connected = true;
/** Maximum message length for session messages. */
private final int maxMessageLength;
/** The capacity of the write buffer, in bytes. */
private final int writeBufferCapacity;
/** If the value is not {@code -1}, indicates the node ID that this
* session is relocating to. */
private long relocatingToNode = -1;
/*
* TBD: Should a managed reference to the ClientSessionListener be
* cached in the ClientSessionImpl for efficiency?
*/
/**
* Constructs an instance of this class with the specified {@code
* sessionService}, {@code identity}, and supported {@code deliveries},
* and stores this instance with the following bindings:<p>
*
* <pre>
* com.sun.sgs.impl.service.session.impl.<idBytes>
* com.sun.sgs.impl.service.session.node.<nodeId>.impl.<idBytes>
*</pre>
* This method should only be called within a transaction.
*
* @param sessionService a client session service
* @param identity the session's identity
* @param deliveries the session's supported delivery requirements
* @param maxMessageLength the maximum session message length
* @throws TransactionException if there is a problem with the
* current transaction
*/
ClientSessionImpl(ClientSessionServiceImpl sessionService,
Identity identity, Set<Delivery> deliveries,
int maxMessageLength)
{
if (sessionService == null) {
throw new NullPointerException("null sessionService");
} else if (identity == null) {
throw new NullPointerException("null identity");
} else if (deliveries == null) {
throw new NullPointerException("null deliveries");
}
this.sessionService = sessionService;
this.identity = identity;
this.deliveries = deliveries;
this.nodeId = sessionService.getLocalNodeId();
this.maxMessageLength = maxMessageLength;
writeBufferCapacity = sessionService.getWriteBufferSize();
DataService dataService = sessionService.getDataService();
ManagedReference<ClientSessionImpl> sessionRef =
dataService.createReference(this);
id = sessionRef.getId();
this.wrappedSessionRef =
dataService.createReference(new ClientSessionWrapper(sessionRef));
idBytes = id.toByteArray();
// TBD: these service bindings could be stored in a BindingKeyedMap
// instead.
dataService.setServiceBinding(getSessionKey(), this);
dataService.setServiceBinding(getSessionNodeKey(), this);
dataService.setServiceBinding(getEventQueueKey(), new EventQueue(this));
logger.log(Level.FINEST, "Stored session, identity:{0} id:{1}",
identity, id);
}
/* -- Implement ClientSession -- */
/** {@inheritDoc} */
public String getName() {
if (!isConnected()) {
throw new IllegalStateException("client session is not connected");
}
String name = identity.getName();
return name;
}
/** {@inheritDoc} */
public Set<Delivery> supportedDeliveries() {
return deliveries;
}
/** {@inheritDoc} */
public int getMaxMessageLength() {
return maxMessageLength;
}
/** {@inheritDoc} */
public boolean isConnected() {
return connected;
}
/** {@inheritDoc}
*
* Enqueues a send event to this client session's event queue for servicing.
*/
public ClientSession send(ByteBuffer message) {
return send(message, Delivery.RELIABLE);
}
/** {@inheritDoc}
*
* Enqueues a send event to this client session's event queue for servicing.
*/
public ClientSession send(ByteBuffer message, final Delivery delivery) {
try {
if (!isConnected()) {
throw new IllegalStateException("client session not connected");
} else if (message == null) {
throw new NullPointerException("null message");
} else if (message.remaining() > maxMessageLength) {
throw new IllegalArgumentException(
"message too long: " + message.remaining() + " > " +
maxMessageLength);
} else {
checkDelivery(delivery);
}
/*
* TBD: Possible optimization: if we have passed our own special
* buffer to the app, we can detect that here and possibly avoid a
* copy. Our special buffer could be one we passed to the
* receivedMessage callback, or we could add a special API to
* pre-allocate buffers. -JM
*/
final byte[] msgBytes = new byte[message.remaining()];
message.asReadOnlyBuffer().get(msgBytes);
if (delivery.equals(Delivery.UNRELIABLE)) {
// Forward unreliable message directly to client session's
// server node.
final ClientSessionServer server =
sessionService.getClientSessionServer(nodeId);
sessionService.taskService.scheduleNonDurableTask(
new AbstractKernelRunnable("SendUnreliableMessage") {
public void run() {
try {
server.send(idBytes, msgBytes, (byte)
delivery.ordinal());
} catch (IOException e) {
if (logger.isLoggable(Level.FINE)) {
logger.logThrow(
Level.FINE, e,
"send message:{0} throws",
HexDumper.format(msgBytes, 0x50));
}
}
}
}, false);
} else {
// Enqueue reliable message for ordered delivery by the
// client session's server node.
addEvent(new SendEvent(msgBytes, delivery));
}
return getWrappedClientSession();
} catch (RuntimeException e) {
if (logger.isLoggable(Level.FINEST)) {
logger.logThrow(Level.FINEST, e,
"send message:{0} throws",
HexDumper.format(message, 0x50));
}
throw e;
}
}
/**
* Throws {@link DeliveryNotSupportedException} if the specified
* {@code delivery} guarantee is not supported by any of this session's
* delivery guarantees.
*
* @param delivery a delivery guarantee
* @throws DeliveryNotSupportedException if the specified {@code
* delivery} guarantee is not supported by any of this
* session's delivery guarantees
*/
private void checkDelivery(Delivery delivery) {
if (delivery == null) {
throw new NullPointerException("null delivery");
}
if (deliveries.contains(delivery)) {
return;
}
for (Delivery d : deliveries) {
if (d.supportsDelivery(delivery)) {
return;
}
}
throw new DeliveryNotSupportedException(
"client session:" + this +
" does not support the delivery guarantee",
delivery);
}
/**
* Initiates a relocation of this client session from the current node
* to {@code newNodeId}. If the client session is no longer connected
* or the session is already relocating then this request is ignored.
*
* @param newNodeId the ID of the node this session is relocating to
*/
void addMoveEvent(long newNodeId) {
if (isConnected() && !isRelocating()) {
addEvent(new MoveEvent(newNodeId));
}
}
/**
* Sets the {@code relocatingToNode} field to the specified node ID.
* This method is invoked when a move event is processed on the
* original node to flag this client session as one that is
* relocating. When relocation is complete, the {@link
* #relocationComplete} method should be invoked on the client
* session's new node to mark the client session as having moved.
*
* @param newNodeId the new node that client session is relocating to
* @throws IllegalStateException if this method is invoked from a node
* other than the session's local node
*/
private void setRelocatingToNode(long newNodeId) {
if (!isLocalSession()) {
throw new IllegalStateException(
"'setRelocating' can only be invoked on the local node:" +
nodeId + " for this session: " + toString());
}
sessionService.getDataService().markForUpdate(this);
relocatingToNode = newNodeId;
}
/**
* Marks this client session as having completed relocation, and then
* services this session's event queue. This method is invoked when
* the associated client connects to the new node to re-establish the
* client session.
*
* @throws IllegalStateException if this method is invoked from a node
* other than the session's local node
*/
void relocationComplete() {
if (relocatingToNode != sessionService.getLocalNodeId()) {
throw new IllegalStateException(
"'relocationComplete' can only be invoked on the local node:" +
nodeId + " for this session: " + toString());
}
sessionService.getDataService().markForUpdate(this);
relocatingToNode = -1;
getEventQueue().serviceEvent();
}
/**
* Returns {@code true} if the session is relocating, and {@code
* false} otherwise.
*
* @return {@code true} if the session is relocating, and {@code
* false} otherwise
*/
public boolean isRelocating() {
return relocatingToNode != -1;
}
/**
* Updates this client session's node ID and bindings to the client
* session to reflect its reassignment to {@code newNodeId}.
*
* @param newNodeId the node this session is relocating to
* @throws IllegalArgumentException if {@code newNodeId} does not match
* the local node ID
*/
void move(long newNodeId) {
if (newNodeId != sessionService.getLocalNodeId()) {
throw new IllegalArgumentException(
"newNodeId:" + newNodeId + " must match the local node ID:" +
sessionService.getLocalNodeId());
}
DataService dataService = sessionService.getDataService();
dataService.markForUpdate(this);
dataService.removeServiceBinding(getSessionNodeKey());
nodeId = newNodeId;
// TBD: this could use a BindingKeyedMap.
dataService.setServiceBinding(getSessionNodeKey(), this);
}
/**
* If the session is connected, enqueues a disconnect event to this
* client session's event queue, and marks this session as disconnected.
*/
void disconnect() {
if (isConnected()) {
addEvent(new DisconnectEvent());
sessionService.getDataService().markForUpdate(this);
connected = false;
}
logger.log(Level.FINEST, "disconnect returns");
}
/* -- Implement NodeAssignment -- */
/** {@inheritDoc} */
public long getNodeId() {
return nodeId;
}
/** {@inheritDoc} */
public long getRelocatingToNodeId() {
return relocatingToNode;
}
/* -- Implement Object -- */
/** {@inheritDoc} */
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
} else if (obj != null && obj.getClass() == this.getClass()) {
ClientSessionImpl session = (ClientSessionImpl) obj;
return
equalsInclNull(identity, session.identity) &&
equalsInclNull(id, session.id);
}
return false;
}
/**
* Returns {@code true} if the given objects are either both
* null, or both non-null and invoking {@code equals} on the first
* object passing the second object returns {@code true}.
*/
private static boolean equalsInclNull(Object obj1, Object obj2) {
if (obj1 == null) {
return obj2 == null;
} else if (obj2 == null) {
return false;
} else {
return obj1.equals(obj2);
}
}
/** {@inheritDoc} */
@Override
public int hashCode() {
return id.hashCode();
}
/** {@inheritDoc} */
@Override
public String toString() {
return getClass().getName() + "[" + identity.getName() + "]@[id:0x" +
id.toString(16) + ",node:" + nodeId + "]";
}
/* -- Serialization methods -- */
private void readObject(ObjectInputStream in)
throws IOException, ClassNotFoundException
{
in.defaultReadObject();
sessionService = ClientSessionServiceImpl.getInstance();
this.id = new BigInteger(1, idBytes);
}
/* -- Other methods -- */
/**
* Returns the ID of this instance as a {@code BigInteger}.
*
* @return the ID of this instance as a {@code BigInteger}
*/
BigInteger getId() {
return id;
}
/**
* Returns the {@code ClientSession} instance for the given {@code
* id}, retrieved from the specified {@code dataService}, or
* {@code null} if the client session isn't bound in the data
* service. This method should only be called within a
* transaction.
*
* @param dataService a data service
* @param id a session ID
* @return the session for the given session {@code id},
* or {@code null}
* @throws TransactionException if there is a problem with the
* current transaction
*/
static ClientSessionImpl getSession(
DataService dataService, BigInteger id)
{
ClientSessionImpl sessionImpl = null;
try {
ManagedReference<?> sessionRef =
dataService.createReferenceForId(id);
sessionImpl = (ClientSessionImpl) sessionRef.get();
} catch (ObjectNotFoundException e) {
}
return sessionImpl;
}
/**
* Returns the wrapped client session for this instance.
* @return the wrapped client session
*/
public ClientSessionWrapper getWrappedClientSession() {
return wrappedSessionRef.get();
}
/**
* Invokes the {@code disconnected} callback on this session's {@code
* ClientSessionListener} (if present and {@code notify} is
* {@code true}), removes the listener and its binding (if present),
* and then removes this session and its bindings from the specified
* {@code dataService}. If the bindings have already been removed from
* the {@code dataService} this method takes no action. This method
* should only be called within a transaction.
*
* @param dataService a data service
* @param graceful {@code true} if disconnection is graceful,
* and {@code false} otherwise
* @param notify {@code true} if the {@code disconnected}
* callback should be invoked
* @throws TransactionException if there is a problem with the
* current transaction
*/
void notifyListenerAndRemoveSession(
final DataService dataService, final boolean graceful, boolean notify)
{
String sessionKey = getSessionKey();
String sessionNodeKey = getSessionNodeKey();
String listenerKey = getListenerKey();
String eventQueueKey = getEventQueueKey();
// Mark this session as disconnected.
dataService.markForUpdate(this);
connected = false;
/*
* Get ClientSessionListener, and remove its binding and
* wrapper if applicable. The listener may not be bound
* in the data service if: the AppListener.loggedIn callback
* either threw a non-retryable exception or returned a
* null listener, or the application removed the
* ClientSessionListener object from the data service.
*/
ClientSessionListener listener = null;
try {
ManagedObject obj = null;
try {
obj = dataService.getServiceBinding(listenerKey);
} catch (ObjectNotFoundException ignore) {
// listener already removed
}
dataService.removeServiceBinding(listenerKey);
if (obj instanceof ListenerWrapper) {
dataService.removeObject(obj);
listener = ((ListenerWrapper) obj).get();
} else {
listener = (ClientSessionListener) obj;
}
} catch (NameNotBoundException e) {
logger.logThrow(
Level.FINE, e,
"removing ClientSessionListener for session:{0} throws",
this);
}
/*
* Remove event queue and associated binding.
*/
try {
ManagedObject eventQueue =
dataService.getServiceBinding(eventQueueKey);
dataService.removeServiceBinding(eventQueueKey);
dataService.removeObject(eventQueue);
} catch (NameNotBoundException e) {
logger.logThrow(
Level.FINE, e,
"removing EventQueue for session:{0} throws",
this);
}
/*
* Invoke listener's 'disconnected' callback if 'notify'
* is true and a listener exists for this client session. If the
* 'disconnected' callback throws a non-retryable exception,
* schedule a task to remove this session and its associated
* bindings without invoking the listener, and rethrow the
* exception so that the currently executing transaction aborts.
*/
if (notify && listener != null) {
try {
listener.disconnected(graceful);
} catch (RuntimeException e) {
if (!isRetryableException(e)) {
logger.logThrow(
Level.WARNING, e,
"invoking disconnected callback on listener:{0} " +
"for session:{1} throws",
listener, this);
sessionService.scheduleTask(
new AbstractKernelRunnable(
"NotifyListenerAndRemoveSession")
{
public void run() {
ClientSessionImpl sessionImpl =
ClientSessionImpl.getSession(
dataService, id);
sessionImpl.notifyListenerAndRemoveSession(
dataService, graceful, false);
}
}, identity);
}
throw e;
}
}
/*
* Remove this session's state and bindings.
*/
try {
dataService.removeServiceBinding(sessionKey);
dataService.removeServiceBinding(sessionNodeKey);
dataService.removeObject(this);
} catch (NameNotBoundException e) {
logger.logThrow(
Level.WARNING, e, "session binding already removed:{0}",
sessionKey);
}
/*
* Remove this session's wrapper object, if it still exists.
*/
try {
dataService.removeObject(wrappedSessionRef.get());
} catch (ObjectNotFoundException e) {
// already removed
}
}
/**
* Returns the {@code ClientSessionServer} for this instance.
*/
private ClientSessionServer getClientSessionServer() {
return sessionService.getClientSessionServer(nodeId);
}
/**
* Returns the key to access this instance from the data service.
*
* @return a key for accessing this {@code ClientSessionImpl} instance
*/
private String getSessionKey() {
return
PKG_NAME + SESSION_COMPONENT + HexDumper.toHexString(idBytes);
}
/**
* Returns the key to access from the data service the {@code
* ClientSessionListener} instance for this instance. If the {@code
* ClientSessionListener} does not implement {@code ManagedObject},
* then the key will be bound to a {@code ListenerWrapper}.
*
* @return a key for accessing the {@code ClientSessionListener} instance
*/
private String getListenerKey() {
return
PKG_NAME + LISTENER_COMPONENT + HexDumper.toHexString(idBytes);
}
/**
* Returns the key to access the event queue of the session with the
* specified {@code sessionId}.
*/
private static String getEventQueueKey(byte[] sessionId) {
return PKG_NAME + QUEUE_COMPONENT + HexDumper.toHexString(sessionId);
}
/**
* Returns the key to access this session's event queue.
*/
private String getEventQueueKey() {
return getEventQueueKey(idBytes);
}
/**
* Returns the key to access this instance from the data service (by
* {@code nodeId} and session {@code idBytes}).
*
* @return a key for accessing the {@code ClientSessionImpl} instance
*/
private String getSessionNodeKey() {
return getNodePrefix(nodeId) + HexDumper.toHexString(idBytes);
}
/**
* Returns the prefix to access from the data service {@code
* ClientSessionImpl} instances with the the specified {@code nodeId}.
*/
private static String getNodePrefix(long nodeId) {
return PKG_NAME + NODE_COMPONENT + nodeId + ".";
}
/**
* Stores the specified client session listener in the specified
* {@code dataService} with following binding:
* <pre>
* com.sun.sgs.impl.service.session.listener.<idBytes>
* </pre>
* This method should only be called within a transaction.
*
* @param dataService a data service
* @param listener a client session listener
* @throws TransactionException if there is a problem with the
* current transaction
*/
void putClientSessionListener(
DataService dataService, ClientSessionListener listener)
{
ManagedObject managedObject =
(listener instanceof ManagedObject) ?
(ManagedObject) listener :
new ListenerWrapper(listener);
String listenerKey = getListenerKey();
// TBD: this could use a BindingKeyedMap.
dataService.setServiceBinding(listenerKey, managedObject);
}
/**
* Returns the client session listener, obtained from the
* specified {@code dataService}, for this session. This method
* should only be called within a transaction.
*
* @param dataService a data service
* @return the client session listener for this session
* @throws TransactionException if there is a problem with the
* current transaction
*/
ClientSessionListener getClientSessionListener(DataService dataService) {
String listenerKey = getListenerKey();
ManagedObject obj = dataService.getServiceBinding(listenerKey);
return
(obj instanceof ListenerWrapper) ?
((ListenerWrapper) obj).get() :
(ClientSessionListener) obj;
}
/**
* A {@code ManagedObject} wrapper for a {@code ClientSessionListener}.
*/
private static class ListenerWrapper
implements ManagedObject, Serializable
{
private static final long serialVersionUID = 1L;
private ClientSessionListener listener;
ListenerWrapper(ClientSessionListener listener) {
assert listener != null && listener instanceof Serializable;
this.listener = listener;
}
ClientSessionListener get() {
return listener;
}
}
/**
* Returns the event queue for the client session with the specified
* {@code sessionId}, or null if the event queue is not bound in the
* data service.
*/
private static EventQueue getEventQueue(byte[] sessionId) {
DataService dataService =
ClientSessionServiceImpl.getInstance().getDataService();
String eventQueueKey = getEventQueueKey(sessionId);
try {
return (EventQueue) dataService.getServiceBinding(eventQueueKey);
} catch (NameNotBoundException e) {
return null;
}
}
/**
* Returns this client session's event queue, or null if the event
* queue is not bound in the data service.
*/
private EventQueue getEventQueue() {
return getEventQueue(idBytes);
}
/**
* Returns {@code true} if session is on local node and is not
* relocating, and returns {@code false} otherwise.
*/
private boolean isLocalSession() {
return nodeId == sessionService.getLocalNodeId() &&
relocatingToNode == -1;
}
/**
* Adds the specified session {@code event} to this session's event
* queue and notifies the client session service on the session's node
* that there is an event to service.
*/
private void addEvent(SessionEvent event) {
EventQueue eventQueue = getEventQueue();
if (eventQueue == null) {
throw new IllegalStateException(
"event queue removed; session is disconnected");
}
boolean isLocalSession = isLocalSession();
/*
* If this session is connected to the local node, the event queue
* is empty, and the session is not relocating, then service the
* event immediately without adding it to the event queue.
*
* Otherwise, add the event to the event queue. If the session is
* not relocating, then if the session is connected locally service
* the head of the event queue, otherwise schedule a task to send a
* request to this session's client session server to service this
* session's event queue.
*
* If the session is relocating, then the servicing of events will
* resume when the client connects to the new node to re-establish
* the client session.
*/
if (isLocalSession && eventQueue.isEmpty() && !isRelocating()) {
logger.log(Level.FINEST, "immediately processing event:{0}", event);
event.serviceEvent(
eventQueue,
sessionService,
sessionService.getHandler(eventQueue.getSessionRefId()));
} else if (!eventQueue.offer(event)) {
throw new ResourceUnavailableException(
"not enough resources to add client session event");
} else if (!isRelocating()) {
if (isLocalSession) {
eventQueue.serviceEvent();
} else {
final ClientSessionServer sessionServer =
getClientSessionServer();
if (sessionServer == null) {
/*
* If the ClientSessionServer for this session has been
* removed, then this session's node has failed and the
* session has been disconnected. The event queue will be
* cleaned up eventually, so there is no need to flag an
* error here.
*/
return;
}
sessionService.getTaskScheduler().scheduleTask(
new AbstractKernelRunnable("ServiceEventQueue") {
public void run() {
sessionService.runIoTask(
new IoRunnable() {
public void run() throws IOException {
sessionServer.serviceEventQueue(idBytes);
} },
nodeId);
}
}, identity);
}
}
}
/**
* Services the event queue for the session with the specified {@code
* sessionId}.
*/
static void serviceEventQueue(byte[] sessionId) {
EventQueue eventQueue = getEventQueue(sessionId);
if (eventQueue != null) {
eventQueue.serviceEvent();
}
}
/**
* Returns the write buffer capacity for this session.
*
* @return the write buffer capacity
*/
int getWriteBufferCapacity() {
return writeBufferCapacity;
}
/**
* Represents an event for a client session.
*/
private abstract static class SessionEvent
implements ManagedObject, Serializable
{
/** The serialVersionUID for this class. */
private static final long serialVersionUID = 1L;
/**
* Services this event, taken from the head of the given {@code
* eventQueue}.
*/
abstract void serviceEvent(EventQueue eventQueue,
ClientSessionServiceImpl sessionService,
ClientSessionHandler handler);
/**
* Returns the cost of this event, which the {@code EventQueue} may
* use to reject events when the total cost is too large. The cost
* of the event is the size (in bytes) of a message generated as a
* result of processing the event. <p>
*
* The default implementation returns a cost of zero.
*
* @return the cost of this event
*/
int getCost() {
return 0;
}
}
/**
* A client session 'send' event, enqueued by a {@code
* ClientSession.send} invocation. When this event commits, a task is
* scheduled to deliver the message, specified during construction, to
* the client session.
*/
static class SendEvent extends SessionEvent {
/** The serialVersionUID for this class. */
private static final long serialVersionUID = 1L;
final byte[] message;
final Delivery delivery;
/**
* Constructs a send event with the given {@code message}.
*/
SendEvent(byte[] message, Delivery delivery) {
this.message = message;
this.delivery = delivery;
}
/** {@inheritDoc} */
void serviceEvent(EventQueue eventQueue,
ClientSessionServiceImpl sessionService,
ClientSessionHandler handler)
{
if (eventQueue == null) {
throw new NullPointerException("null eventQueue");
} else if (sessionService == null) {
throw new NullPointerException("null sessionService");
} else if (handler == null) {
throw new NullPointerException("null handler");
}
sessionService.checkContext().addCommitAction(
eventQueue.getSessionRefId(),
handler.new SendMessageAction(this),
false);
}
/** Use the message length as the cost for sending messages. */
@Override
int getCost() {
return message.length;
}
/** {@inheritDoc} */
@Override
public String toString() {
return getClass().getName();
}
}
/**
* A client session 'move' event. This event is processed on the
* client session's old node to mark the session as relocating. Once
* the session is marked for relocation, the associated session's event
* processing is suspended until the session is relocated to the new
* node. <p>
*
* When this event commits, a task is scheduled to commence preparation
* for the client session to relocate. The first action is to obtain a
* relocation key from the new node and notify interested parties to
* prepare for relocation. See {@link ClientSessionHandler#MoveAction}
* for details.
*/
private static class MoveEvent extends SessionEvent {
/** The serialVersionUID for this class. */
private static final long serialVersionUID = 1L;
private final long newNodeId;
/** Constructs a move event. */
MoveEvent(long newNodeId) {
this.newNodeId = newNodeId;
}
/** {@inheritDoc} */
void serviceEvent(EventQueue eventQueue,
ClientSessionServiceImpl sessionService,
ClientSessionHandler handler)
{
ClientSessionImpl sessionImpl = eventQueue.getClientSession();
sessionImpl.setRelocatingToNode(newNodeId);
Node newNode = sessionService.watchdogService.getNode(newNodeId);
if (newNode == null) {
if (logger.isLoggable(Level.FINE)) {
logger.log(Level.FINE,
"Session:{0} unable to relocate from node:{1} " +
"to FAILED node:{2}", this,
sessionService.getLocalNodeId(), newNodeId);
}
} else if (handler == null) {
if (logger.isLoggable(Level.FINE)) {
logger.log(Level.FINE,
"DISCONNECTED Session:{0} unable to relocate " +
"from node:{1} to node:{2}", this,
sessionService.getLocalNodeId(), newNodeId);
}
} else {
if (logger.isLoggable(Level.FINE)) {
logger.log(Level.FINE,
"Session:{0} to relocate " +
"from node:{1} to node:{2}", this,
sessionService.getLocalNodeId(), newNodeId);
}
sessionService.checkContext().addCommitAction(
eventQueue.getSessionRefId(),
handler.new MoveAction(newNode), false);
}
}
}
/**
* A client session 'disconnect' event, enqueued when the session's
* associated {@code ClientSessionWrapper} is removed, or if there is a
* problem during client login, after the client session has been
* persisted. <p>
*
* When this event commits, a task is scheduled to disconnect the
* client session, cleanup its persistent data, and notify the client
* session's listener of the disconnection.
*/
private static class DisconnectEvent extends SessionEvent {
/** The serialVersionUID for this class. */
private static final long serialVersionUID = 1L;
/** Constructs a disconnect event. */
DisconnectEvent() { }
/** {@inheritDoc} */
void serviceEvent(EventQueue eventQueue,
ClientSessionServiceImpl sessionService,
ClientSessionHandler handler)
{
sessionService.checkContext().addCommitAction(
eventQueue.getSessionRefId(),
handler.new DisconnectAction(), false);
}
/** {@inheritDoc} */
@Override
public String toString() {
return getClass().getName();
}
}
/**
* The session's event queue.
*/
private static class EventQueue
implements ManagedObjectRemoval, Serializable
{
/** The serialVersionUID for this class. */
private static final long serialVersionUID = 1L;
/** The managed reference to the queue's session. */
private final ManagedReference<ClientSessionImpl> sessionRef;
/** The managed reference to the managed queue. */
private final ManagedReference<ManagedQueue<SessionEvent>> queueRef;
/** The number of bytes of the write buffer currently available. */
private int writeBufferAvailable;
/**
* Constructs an event queue for the specified {@code sessionImpl}.
*/
EventQueue(ClientSessionImpl sessionImpl) {
DataService dataService =
sessionImpl.sessionService.getDataService();
sessionRef = dataService.createReference(sessionImpl);
queueRef = dataService.createReference(
new ManagedQueue<SessionEvent>());
writeBufferAvailable = sessionImpl.writeBufferCapacity;
}
/**
* Attempts to enqueue the specified {@code event}, and returns
* {@code true} if successful, and {@code false} otherwise.
*
* @param event the event
* @return {@code true} if successful, and {@code false} otherwise
* @throws MessageRejectedException if the cost of the event
* exceeds the available buffer space in the queue
*/
boolean offer(SessionEvent event) {
int cost = event.getCost();
if (cost > writeBufferAvailable) {
throw new MessageRejectedException(
"Not enough queue space: " + writeBufferAvailable +
" bytes available, " + cost + " requested");
}
if (logger.isLoggable(Level.FINEST)) {
logger.log(
Level.FINEST,
"Adding event:{0} to event queue, localNodeId:{1}", event,
ClientSessionServiceImpl.getInstance().getLocalNodeId());
}
boolean success = getQueue().offer(event);
if (success && cost > 0) {
ClientSessionServiceImpl.getInstance().
getDataService().markForUpdate(this);
writeBufferAvailable -= cost;
if (logger.isLoggable(Level.FINEST)) {
logger.log(Level.FINEST,
"{0} reserved {1,number,#} leaving {2,number,#}",
this, cost, writeBufferAvailable);
}
}
return success;
}
/**
* Returns the client session for this queue.
*/
ClientSessionImpl getClientSession() {
return sessionRef.get();
}
/**
* Returns the client session ID for this queue.
*/
BigInteger getSessionRefId() {
return sessionRef.getId();
}
/**
* Returns the managed queue object.
*/
ManagedQueue<SessionEvent> getQueue() {
return queueRef.get();
}
/**
* Returns {@code true} if the event queue is empty.
*/
boolean isEmpty() {
return getQueue().isEmpty();
}
/**
* Throws a retryable exception if the event queue is not in a
* state to process the next event.
*/
void checkState() {
// TBD: is there any state to check here?
}
/**
* Processes (at least) the first event in the queue.
*/
void serviceEvent() {
checkState();
ClientSessionServiceImpl sessionService =
ClientSessionServiceImpl.getInstance();
ClientSessionHandler handler =
sessionService.getHandler(getSessionRefId());
ClientSessionImpl sessionImpl = getClientSession();
if (logger.isLoggable(Level.FINEST)) {
logger.log(Level.FINEST,
"Servicing event queue, node:{0} session:{1}",
sessionService.getLocalNodeId(),
getSessionRefId());
}
if (handler == null || !sessionImpl.isLocalSession() ||
sessionImpl.isRelocating())
{
// Only service events on the session's local node, so return.
// The session may be moving, and this might be a left over
// serviceEventQueue request
if (logger.isLoggable(Level.FINE)) {
logger.log(
Level.FINE,
"Attempt to service event queue, localNodeId:{0} " +
"session:{1} handler:{2} sessionNodeId:{3} " +
"relocatingToNodeId:{4}",
sessionService.getLocalNodeId(), getSessionRefId(),
handler, sessionImpl.nodeId,
sessionImpl.relocatingToNode);
}
return;
}
ManagedQueue<SessionEvent> eventQueue = getQueue();
DataService dataService =
ClientSessionServiceImpl.getInstance().getDataService();
for (int i = 0; i < sessionService.eventsPerTxn; i++) {
SessionEvent event = eventQueue.poll();
if (event == null) {
// no more events
// TBD: should the session's task queue for servicing
// events be cleared?
return;
}
logger.log(Level.FINEST, "processing event:{0}", event);
int cost = event.getCost();
if (cost > 0) {
// TBD: this update is costly.
dataService.markForUpdate(this);
writeBufferAvailable += cost;
if (logger.isLoggable(Level.FINEST)) {
logger.log(Level.FINEST,
"{0} cleared reservation of " +
"{1,number,#} bytes, leaving {2,number,#}",
this, cost, writeBufferAvailable);
}
}
event.serviceEvent(this, sessionService, handler);
}
// Make sure the next event gets serviced.
if (eventQueue.peek() != null) {
sessionService.addServiceEventQueueTask(sessionImpl.idBytes);
}
}
/* -- Implement ManagedObjectRemoval -- */
/** {@inheritDoc} */
public void removingObject() {
try {
DataService dataService =
ClientSessionServiceImpl.getInstance().getDataService();
dataService.removeObject(queueRef.get());
} catch (ObjectNotFoundException e) {
// already removed.
}
}
}
/**
* A persistent task to schedule tasks to notify (in succession) the
* client session listener of each disconnected session on a given
* failed node and to clean up the persistent data and bindings of
* those client sessions. In a single task, one disconnected session
* is scheduled to be handled, and then this task is rescheduled to
* schedule the handling of the next disconnected client session (if
* one exists).
*/
static class HandleNextDisconnectedSessionTask
implements Task, Serializable
{
/** The serialVersionUID for this class. */
private static final long serialVersionUID = 1L;
/** The prefix for client sessions on the failed node. */
private final String nodePrefix;
/** The last session key handled, initially the {@code nodePrefix}. */
private String lastKey;
/**
* Constructs an instance of this class with the specified
* {@code nodeId}.
*/
HandleNextDisconnectedSessionTask(long nodeId) {
nodePrefix = getNodePrefix(nodeId);
lastKey = nodePrefix;
}
/** {@inheritDoc} */
public void run() {
DataService dataService =
ClientSessionServiceImpl.getInstance().getDataService();
// TBD: this could use a BindingKeyedMap.
String key = dataService.nextServiceBoundName(lastKey);
if (key != null && key.startsWith(nodePrefix)) {
TaskService taskService =
ClientSessionServiceImpl.getTaskService();
taskService.scheduleTask(
new CleanupDisconnectedSessionTask(key));
lastKey = key;
taskService.scheduleTask(this);
}
}
}
/**
* A persistent task to clean up a client session bound to a
* given {@code key} (specified during construction), by
* invoking the {@code notifyListenerAndRemoveSession} method
* on that client session.
*/
private static class CleanupDisconnectedSessionTask
implements Task, Serializable
{
/** The serialVersionUID for this class. */
private static final long serialVersionUID = 1L;
/** The key for the client session. */
private final String key;
/**
* Constructs an instance of this class with the specified
* {@code key}.
*/
CleanupDisconnectedSessionTask(String key) {
this.key = key;
}
/** {@inheritDoc} */
public void run() {
DataService dataService =
ClientSessionServiceImpl.getInstance().getDataService();
ClientSessionImpl sessionImpl =
(ClientSessionImpl) dataService.getServiceBinding(key);
sessionImpl.notifyListenerAndRemoveSession(
dataService, false, true);
}
}
}