/*******************************************************************************
* Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.internal.sessions.coordination;
import org.eclipse.persistence.sessions.SessionProfiler;
import org.eclipse.persistence.sessions.coordination.*;
import org.eclipse.persistence.exceptions.*;
import java.util.Iterator;
import java.util.Map;
/**
* <p>
* <b>Purpose</b>: Synchronous and asynchronous propagation of remote commands
* <p>
* <b>Description</b>: Maintains a reference to the RemoteCommandManager to obtain
* the connection information required to send the commands. In sync mode the caller
* is blocked until the command has been sent along all of the connections. If in
* async mode then a CommandPropagator instance is further created for each of the
* connections and control is returned to the caller while the threads send the
* command to the remote services.
* <p>
*/
public class CommandPropagator implements Runnable {
/** Reference to manager to get connections, etc. */
protected RemoteCommandManager rcm;
/** The command to send */
protected Command command;
/** The command to send */
protected byte[] commandBytes;
/** Connection to send to */
protected RemoteConnection connection;
/**
* Constructor used to create the main propagator
*/
public CommandPropagator(RemoteCommandManager rcm, Command command, byte[] commandBytes) {
super();
this.rcm = rcm;
this.command = command;
this.commandBytes = commandBytes;
}
/**
* Constructor used to create the async propagator threads
*/
public CommandPropagator(RemoteCommandManager rcm, Command command, byte[] commandBytes, RemoteConnection connection) {
this(rcm, command, commandBytes);
this.connection = connection;
}
/**
* INTERNAL:
* Returns the remote command manager
*/
protected RemoteCommandManager getRemoteCommandManager() {
return rcm;
}
/**
* INTERNAL:
* Returns the command to be sent
*/
protected Command getCommand() {
return command;
}
/**
* INTERNAL:
* Synchronously propagate the command
*/
public void synchronousPropagateCommand() {
rcm.logDebug("sync_propagation", (Object[])null);
Iterator connections = rcm.getTransportManager().getConnectionsToExternalServicesForCommandPropagation().values().iterator();
while (connections.hasNext()) {
connection = (RemoteConnection)connections.next();
this.propagateCommand(connection);
}
}
/**
* INTERNAL:
* Asynchronously propagate the command
*/
public void asynchronousPropagateCommand() {
// The async logic is in the run() method
rcm.logDebug("async_propagation", (Object[])null);
this.rcm.getServerPlatform().launchContainerRunnable(this);
}
/**
* INTERNAL:
* Propagate the command to the specified connection.
*/
public void propagateCommand(RemoteConnection connection) {
Object[] arguments = { command.getClass().getName(), connection.getServiceId() };
rcm.logDebug("propagate_command_to", arguments);
try {
// The result will be null on success, and an exception string on failure
Object result = null;
// PERF: Support plugable serialization.
if (this.commandBytes != null) {
result = connection.executeCommand(this.commandBytes);
} else {
result = connection.executeCommand(this.command);
}
if (result != null) {
// An error occurred executing the remote command
handleExceptionFromRemoteExecution(connection, (String)result);
}
} catch (CommunicationException comEx) {
// We got a comms exception.
this.handleCommunicationException(connection, comEx);
}
}
/**
* INTERNAL:
* We received the specified exception String while executing the command
* over the specified connection. Turn it into a RemoteCommandManagerException
* and throw it on this, the client side.
*/
public void handleExceptionFromRemoteExecution(RemoteConnection conn, String exString) {
// Log the error and pass the exception off to the handler
Object[] args = { conn.getServiceId(), exString };
rcm.logWarning("failed_command_propagation", args);
// Build an RCMException and concoct an RTException to stick inside
RemoteCommandManagerException rcmException = RemoteCommandManagerException.unableToPropagateCommand(conn.toString(), new Exception(exString));
rcm.handleException(rcmException);
}
/**
* INTERNAL:
* We received the specified CommunicationException trying to execute the command
* over the specified connection. We treat CommunicationExceptions as the
* transport-generic wrapper exception that wraps the transport exception,
* so the real exception that interests us is inside.
*/
public void handleCommunicationException(RemoteConnection conn, CommunicationException comEx) {
// If the removeOnError flag is set then just log a warning and discard connection
if (rcm.getTransportManager().shouldRemoveConnectionOnError()) {
Object[] args = { conn.getServiceId(), comEx.getInternalException() };
rcm.logWarning("drop_connection_on_error", args);
rcm.getTransportManager().removeConnectionToExternalService(conn);
} else {
// Otherwise, log the error and pass the exception off to the handler
Object[] args = { conn.getServiceId(), comEx };
rcm.logWarning("failed_command_propagation", args);
RemoteCommandManagerException rcmException = RemoteCommandManagerException.unableToPropagateCommand(conn.toString(), comEx.getInternalException());
try {
rcm.handleException(rcmException);
} catch (RuntimeException ex) {
// If the connection is set then we are an async connection thread:
// in that case the method is called from a separate thread
// and no one could catch it.
if (connection == null) {
// rethrow exception
throw ex;
}
}
}
}
/**
* INTERNAL:
* This is the execution method of the async propagation thread. It will create
* other threads, one each for the remote connections, to propagate the command.
*/
public void run() {
// If the connection is set then we are an async connection thread
if (this.connection != null) {
this.rcm.getCommandProcessor().startOperationProfile(SessionProfiler.CacheCoordination);
try {
propagateCommand(this.connection);
} finally {
this.rcm.getCommandProcessor().endOperationProfile(SessionProfiler.CacheCoordination);
}
} else {
Map mapConnections = this.rcm.getTransportManager().getConnectionsToExternalServicesForCommandPropagation();
Iterator iterator = mapConnections.values().iterator();
if (mapConnections.size() == 1) {
// There is only one connection - no need for yet another thread.
// Set the connection into the current one
// so that it's recognized as async propagation in handleCommunicationException method.
this.connection = (RemoteConnection)iterator.next();
propagateCommand(this.connection);
} else {
// This is the top level thread. We need to spawn off a bunch of async connection threads
while (iterator.hasNext()) {
RemoteConnection remoteConnection = (RemoteConnection)iterator.next();
CommandPropagator propagator = new CommandPropagator(this.rcm, this.command, this.commandBytes, remoteConnection);
this.rcm.getServerPlatform().launchContainerRunnable(propagator);
}
}
}
}
}