I created a sucessful RMI server, thank god for that :)
It works perfectly..
I have a JForm and it gets activated clicking on a button.
Altough i wanted to create too a button to deactivate it, but i am having a problems to unexport it.
Ok then and this is the way i was trying to exporting and terminating the RMI Server
private void btStopServerActionPerformed(java.awt.event.ActionEvent evt) {
try {
// Nome do objecto
String objectname = txtObjectName.getText();
// obtem o número da porta
int port = Integer.parseInt(txtServerPort.getText());
RemoteMessageObject remote = new RemoteMessageObject();
Registry registry = LocateRegistry.getRegistry(port);
UnicastRemoteObject.unexportObject(LocateRegistry.getRegistry(port), true);
registry.unbind(objectname);
System.out.println("Server offline");
} catch (IOException ex) {
Logger.getLogger(ServerGUI.class.getName()).log(Level.SEVERE, null, ex);
} catch (NotBoundException ex) {
Logger.getLogger(ServerGUI.class.getName()).log(Level.SEVERE, null, ex);
}
}
I get this exception:
java.rmi.NoSuchObjectException: object not exported
at the line:
UnicastRemoteObject.unexportObject(LocateRegistry.getRegistry(port), true);
What am i doing wrong here?
Solved................
I discovered it before :P
Anywway thanks #EJP for the correct answer.
So the solution for me was to create the Register when the class starts as a public variable, so it could be use inside both click events (Start server and stop server).
I removed too a lot of nonsense stuff that was not necessary for disabling the RMI server just like #EJP sayed.
Its now working this way:
private void btStopServerActionPerformed(java.awt.event.ActionEvent evt) {
try {
// Nome do objecto
String objectname = txtObjectName.getText();
// obtem o número da porta
int port = Integer.parseInt(txtServerPort.getText());
Registry registry = LocateRegistry.getRegistry(port);
UnicastRemoteObject.unexportObject(this.registry, true);
registry.unbind(objectname);
System.out.println("Server offline");
} catch (IOException ex) {
GuiUtils.addText(txtLog, "Erro", "Servidor desligado");
btStopServer.setEnabled(false);
btStartServer.setEnabled(true);
} catch (NotBoundException ex) {
Logger.getLogger(ServerGUI.class.getName()).log(Level.SEVERE, null, ex);
}
}
You need to unexport the object returned by LocateRegistry.createRegistry(). The object returned by getRegistry() isn't the actual Registry object, it is a stub, and you can't unexport those.
But unexporting the Registry and then calling unbind() doesn't make sense. Doing it the other way round makes a little sense, but not much.
And you also have to unexport your own remote object.
And creating a new remote object in a method that is trying to unexport the existing one doesn't make sense either.
Related
I have a java application running on WebSphere 8.5.5.12 server. I connect to other applications via MQ. I have faced a performance issue with the application and found that whenever the MQ reply is getting timeout, the Queue connection was not closed properly. I have fixed the issue. I am planning to increase the Maximum connection for the particular Queue Connection factory and i want to get the number of connection used/opened in the Queue Connection Factory via code, so that i can increase the maximum connections accordingly based on the traffic/volume. Any leads would be much helpful.
To learn the number of connections used and the number of queues opened by an application, you can use the MQSC DISPLAY CONN command like this:-
DISPLAY CONN(*) TYPE(ALL) ALL WHERE(OBJNAME EQ reply-q-name)
This will show you all the connections and all the open handles.
You can also discover exactly the same data using a programatic interface called PCF commands, although given how many excellent MQ admin tools there are out there, I'm not sure why you would need to do this "via code" as you put it?
For your second part of your question, how do you change the maximum connections based on load.
I have a some sample code using a datasource that may help to answer you question. Where I using name=built-in-derby-datasource, you can change the name to your Queue Connection factory name. If you need the lookup, change this jndi name jdbc/built-in-derby-datasource to your Queue Connection factory jndi name.
The code will get the admin client giving you access to queryMBeans. After you have the mbean, you can change maximum connections dynamically while the server is running.
#SuppressWarnings("unchecked")
public void AdminClientExample()
{
Object adminClient = null;
// Need to set the properties, type, host and port, defaults likely will work for most
Properties acProps = new Properties();
acProps.setProperty(AdminClient.CONNECTOR_TYPE, AdminClient.CONNECTOR_TYPE_SOAP);
acProps.setProperty(AdminClient.CONNECTOR_HOST, "localhost");
acProps.setProperty(AdminClient.CONNECTOR_PORT, "8880");
// Set if security is enabled
//acProps.setProperty(AdminClient.CONNECTOR_SECURITY_ENABLED, "true");
//acProps.setProperty(AdminClient.USERNAME, "userid");
//acProps.setProperty(AdminClient.PASSWORD, "userid password");
try
{
adminClient = AdminClientFactory.createAdminClient(acProps);
}
catch (Exception e)
{
e.printStackTrace();
}
ObjectInstance obi = null;
ObjectName obn = null;
Set<ObjectInstance> s = null;
try {
// The two types to use are J2CConnectionFactory and DataSource if searching through a list of mbeans of that type.
// type=J2CConnectionFactory
// type=DataSource
// obn = new ObjectName("WebSphere:type=DataSource,*");
// s1 =((AdminClient)adminClient).queryMBeans(obn, null); // search through s1
// You can provide the name like this,
obn = new ObjectName("WebSphere:name=built-in-derby-datasource,*");
s =((AdminClient)adminClient).queryMBeans(obn, null);
// s should contain WebSphere:name=built-in-derby-datasource,process=server1,platform=dynamicproxy,node=DefaultNode01,JDBCProvider=Derby JDBC Provider (XA),diagnosticProvider=true,j2eeType=JDBCDataSource,J2EEServer=server1,Server=server1,version=9.0.0.11,type=DataSource,mbeanIdentifier=cells/DefaultCell01/resources.xml#DataSource_9007001,JDBCResource=Derby JDBC Provider (XA),cell=DefaultCell01,spec=1.0
} catch (Exception e) {
e.printStackTrace();
}
if (s == null) {
System.out.println("Did not find MBeans querying for object name " + obn.toString());
return;
} else {
obi = s.iterator().next();
}
// Normally the application using the connection pool will have
// already done the lookup which creates the objects
// required to change maxConnections. This lookup is only for
// this example.
InitialContext ctx;
try {
ctx = new InitialContext();
ctx.lookup("jdbc/built-in-derby-datasource");
} catch (Exception e) {
e.printStackTrace();
}
// show the connection pool contents
Object [] parms = null;
String [] parmsTypes = null;
try {
String ss = (String) ((AdminClient)adminClient).invoke(obi.getObjectName(), "showPoolContents", parms, parmsTypes);
System.out.println(ss);
} catch (Exception e) {
e.printStackTrace();
}
// get maxConnections
try {
Object maxConnections = ((AdminClient)adminClient).getAttribute(obi.getObjectName(), "maxConnections");
System.out.println(maxConnections);
} catch (Exception e) {
e.printStackTrace();
}
// change the maxConnections to 11,
try {
Integer it = new Integer(11);
Attribute at = new Attribute("maxConnections", it);
((AdminClient)adminClient).setAttribute(obi.getObjectName(), at );
} catch (Exception e) {
e.printStackTrace();
}
// show the connection pool contents, maxConnection now should be 11.
// or you can use the get maxConnection to check
// the changed value.
try {
String ss = (String) ((AdminClient)adminClient).invoke(obi.getObjectName(), "showPoolContents", parms, parmsTypes);
System.out.println(ss);
// or
Object maxConnections = ((AdminClient)adminClient).getAttribute(obi.getObjectName(), "maxConnections");
System.out.println(maxConnections);
} catch (Exception e) {
e.printStackTrace();
}
}
I'm frensh so sorry for my english.
I'm trying to start a server rmi but the application stop whitout error :
Here my code:
public class Server {
public static void main(String[] args) {
try {
RemoteFunction skeleton = (RemoteFunction) UnicastRemoteObject.exportObject(new FunctionImpl(), 0);
int port = Integer.parseInt(Jndiprop.getString("port"));
Registry registry = LocateRegistry.createRegistry(port);
registry.rebind(Jndiprop.getString("url"), skeleton);
System.out.println("Rmi start");
} catch (Exception e) {
e.printStackTrace();
}
}
}
the port and the url are ok.
Someone can help me ?
You must store the Registry in a static variable. Otherwise it can be garbage-collected, which leads to a train of events that allows the whole JVM to exit.
In java RMI i am building a chat application. But i am not able to figure out a way to find out, whether the IP which is hitting my server is from my internal organization network(INTRANET) or from external world(INTERNET).
Right now i am using
try {
System.setProperty("java.rmi.server.hostname",InetAddress.getLocalHost().getHostAddress());
Registry statusRegistry = LocateRegistry.createRegistry(ChatConstants.statusPort);
ChatInterface chat = new ChatImpl(ChatConstants.statusPort) ;
statusRegistry.rebind("statusconnection",chat);
System.out.println("RMIStatusConnection Server is started...");
} catch (RemoteException e) {
System.out.println("RMIStatusConnection failed...");
e.printStackTrace();
} catch (UnknownHostException e) {
e.printStackTrace();
}
Try RemoteServer.getClientHost(), but it may only provide the address of the nearest NAT device.
NB there's not much point in setting java.rmi.server.hostname like that. That's the default. You only need to set it if there's something wrong with the default setting.
Using JXTA 2.6 from http://jxse.kenai.com/ I want to create application that can run multiple peers on one or more hosts. The peers should be able to find each other in a group and send direct messages as well as propagate messages.
What would a simple hello world type of application look like that meet these requirements?
I created this question with the intention of supplying a tutorial like answer, an answer I tried very hard to find two months ago when starting to look at JXTA for a uni project. Feel free to add your own answers or improve on mine. I will wait a few days and accept the best one.
Introduction to JXTA 2.6 Peer discovery and pipe messaging
The guide I wish I had 2 months ago =)
After spending a lot of time during a university course building
a JXTA p2p application I feel a lot of the frustrations and
confusion I went through could have been avoided with a good
starting point.
The jar files you will need can be found here:
https://oss.sonatype.org/content/repositories/comkenaijxse-057/com/kenai/jxse/jxse/2.6/jxse-2.6.jar
http://sourceforge.net/projects/practicaljxta/files/lib-dependencies-2.6.zip/download
Throw them into Yourproject/lib, open up eclipse, create a new project "Yourproject" and it should sort out
importing the libraries for you.
You will soon come to realize that almost any information on the web is out dated, very out dated.
You will also run into a lot of very confusing error messages and most of them can be avoided by
going through this check list.
Is your firewall turned off or at least open for the ports you use?
You can disable iptables using "sudo service iptables stop" under Fedora.
Check spelling! Many times when joining groups or trying to send messages spelling the group name wrong or not using the
exact same advertisement when looking for peers and services or opening pipes will cause very confusing messages.
Was trying to figure out why my pipe connections timed out when I spotted the group names being "Net info" and "Net_info".
Are you using a JXTA home directory? One per each peer you run on the same computer?
Do you really use a unique peer id? The seed provided to IDFactory need to be long enough or else you will get duplicates.
Turn off SELinux. I have had SELinux turned off during the development but can imagine it causing errors.
While it is common to group all fields together I introduce them as I go to show where they are needed.
Note: This will not work in 2.7. Some issue with PSE membership I think.
public class Hello implements DiscoveryListener, PipeMsgListener {
// When developing you should handle these exceptions, I don't to lessen the clutter of start()
public static void main(String[] args) throws PeerGroupException, IOException {
// JXTA logs a lot, you can configure it setting level here
Logger.getLogger("net.jxta").setLevel(Level.ALL);
// Randomize a port to use with a number over 1000 (for non root on unix)
// JXTA uses TCP for incoming connections which will conflict if more than
// one Hello runs at the same time on one computer.
int port = 9000 + new Random().nextInt(100);
Hello hello = new Hello(port);
hello.start();
hello.fetch_advertisements();
}
private String peer_name;
private PeerID peer_id;
private File conf;
private NetworkManager manager;
public Hello(int port) {
// Add a random number to make it easier to identify by name, will also make sure the ID is unique
peer_name = "Peer " + new Random().nextInt(1000000);
// This is what you will be looking for in Wireshark instead of an IP, hint: filter by "jxta"
peer_id = IDFactory.newPeerID(PeerGroupID.defaultNetPeerGroupID, peer_name.getBytes());
// Here the local peer cache will be saved, if you have multiple peers this must be unique
conf = new File("." + System.getProperty("file.separator") + peer_name);
// Most documentation you will find use a deprecated network manager setup, use this one instead
// ADHOC is usually a good starting point, other alternatives include Edge and Rendezvous
try {
manager = new NetworkManager(
NetworkManager.ConfigMode.ADHOC,
peer_name, conf.toURI());
}
catch (IOException e) {
// Will be thrown if you specify an invalid directory in conf
e.printStackTrace();
}
NetworkConfigurator configurator;
try {
// Settings Configuration
configurator = manager.getConfigurator();
configurator.setTcpPort(port);
configurator.setTcpEnabled(true);
configurator.setTcpIncoming(true);
configurator.setTcpOutgoing(true);
configurator.setUseMulticast(true);
configurator.setPeerID(peer_id);
}
catch (IOException e) {
// Never caught this one but let me know if you do =)
e.printStackTrace();
}
}
private static final String subgroup_name = "Make sure this is spelled the same everywhere";
private static final String subgroup_desc = "...";
private static final PeerGroupID subgroup_id = IDFactory.newPeerGroupID(PeerGroupID.defaultNetPeerGroupID, subgroup_name.getBytes());
private static final String unicast_name = "This must be spelled the same too";
private static final String multicast_name = "Or else you will get the wrong PipeID";
private static final String service_name = "And dont forget it like i did a million times";
private PeerGroup subgroup;
private PipeService pipe_service;
private PipeID unicast_id;
private PipeID multicast_id;
private PipeID service_id;
private DiscoveryService discovery;
private ModuleSpecAdvertisement mdadv;
public void start() throws PeerGroupException, IOException {
// Launch the missiles, if you have logging on and see no exceptions
// after this is ran, then you probably have at least the jars setup correctly.
PeerGroup net_group = manager.startNetwork();
// Connect to our subgroup (all groups are subgroups of Netgroup)
// If the group does not exist, it will be automatically created
// Note this is suggested deprecated, not sure what the better way is
ModuleImplAdvertisement mAdv = null;
try {
mAdv = net_group.getAllPurposePeerGroupImplAdvertisement();
} catch (Exception ex) {
System.err.println(ex.toString());
}
subgroup = net_group.newGroup(subgroup_id, mAdv, subgroup_name, subgroup_desc);
// A simple check to see if connecting to the group worked
if (Module.START_OK != subgroup.startApp(new String[0]))
System.err.println("Cannot start child peergroup");
// We will spice things up to a more interesting level by sending unicast and multicast messages
// In order to be able to do that we will create to listeners that will listen for
// unicast and multicast advertisements respectively. All messages will be handled by Hello in the
// pipeMsgEvent method.
unicast_id = IDFactory.newPipeID(subgroup.getPeerGroupID(), unicast_name.getBytes());
multicast_id = IDFactory.newPipeID(subgroup.getPeerGroupID(), multicast_name.getBytes());
pipe_service = subgroup.getPipeService();
pipe_service.createInputPipe(get_advertisement(unicast_id, false), this);
pipe_service.createInputPipe(get_advertisement(multicast_id, true), this);
// In order to for other peers to find this one (and say hello) we will
// advertise a Hello Service.
discovery = subgroup.getDiscoveryService();
discovery.addDiscoveryListener(this);
ModuleClassAdvertisement mcadv = (ModuleClassAdvertisement)
AdvertisementFactory.newAdvertisement(ModuleClassAdvertisement.getAdvertisementType());
mcadv.setName("STACK-OVERFLOW:HELLO");
mcadv.setDescription("Tutorial example to use JXTA module advertisement Framework");
ModuleClassID mcID = IDFactory.newModuleClassID();
mcadv.setModuleClassID(mcID);
// Let the group know of this service "module" / collection
discovery.publish(mcadv);
discovery.remotePublish(mcadv);
mdadv = (ModuleSpecAdvertisement)
AdvertisementFactory.newAdvertisement(ModuleSpecAdvertisement.getAdvertisementType());
mdadv.setName("STACK-OVERFLOW:HELLO");
mdadv.setVersion("Version 1.0");
mdadv.setCreator("sun.com");
mdadv.setModuleSpecID(IDFactory.newModuleSpecID(mcID));
mdadv.setSpecURI("http://www.jxta.org/Ex1");
service_id = IDFactory.newPipeID(subgroup.getPeerGroupID(), service_name.getBytes());
PipeAdvertisement pipeadv = get_advertisement(service_id, false);
mdadv.setPipeAdvertisement(pipeadv);
// Let the group know of the service
discovery.publish(mdadv);
discovery.remotePublish(mdadv);
// Start listening for discovery events, received by the discoveryEvent method
pipe_service.createInputPipe(pipeadv, this);
}
private static PipeAdvertisement get_advertisement(PipeID id, boolean is_multicast) {
PipeAdvertisement adv = (PipeAdvertisement )AdvertisementFactory.
newAdvertisement(PipeAdvertisement.getAdvertisementType());
adv.setPipeID(id);
if (is_multicast)
adv.setType(PipeService.PropagateType);
else
adv.setType(PipeService.UnicastType);
adv.setName("This however");
adv.setDescription("does not really matter");
return adv;
}
#Override public void discoveryEvent(DiscoveryEvent event) {
// Found another peer! Let's say hello shall we!
// Reformatting to create a real peer id string
String found_peer_id = "urn:jxta:" + event.getSource().toString().substring(7);
send_to_peer("Hello", found_peer_id);
}
private void send_to_peer(String message, String found_peer_id) {
// This is where having the same ID is important or else we wont be
// able to open a pipe and send messages
PipeAdvertisement adv = get_advertisement(unicast_id, false);
// Send message to all peers in "ps", just one in our case
Set<PeerID> ps = new HashSet<PeerID>();
try {
ps.add((PeerID)IDFactory.fromURI(new URI(found_peer_id)));
}
catch (URISyntaxException e) {
// The JXTA peer ids need to be formatted as proper urns
e.printStackTrace();
}
// A pipe we can use to send messages with
OutputPipe sender = null;
try {
sender = pipe_service.createOutputPipe(adv, ps, 10000);
}
catch (IOException e) {
// Thrown if there was an error opening the connection, check firewall settings
e.printStackTrace();
}
Message msg = new Message();
MessageElement fromElem = null;
MessageElement msgElem = null;
try {
fromElem = new ByteArrayMessageElement("From", null, peer_id.toString().getBytes("ISO-8859-1"), null);
msgElem = new ByteArrayMessageElement("Msg", null, message.getBytes("ISO-8859-1"), null);
} catch (UnsupportedEncodingException e) {
// Yepp, you want to spell ISO-8859-1 correctly
e.printStackTrace();
}
msg.addMessageElement(fromElem);
msg.addMessageElement(msgElem);
try {
sender.send(msg);
} catch (IOException e) {
// Check, firewall, settings.
e.printStackTrace();
}
}
#Override public void pipeMsgEvent(PipeMsgEvent event) {
// Someone is sending us a message!
try {
Message msg = event.getMessage();
byte[] msgBytes = msg.getMessageElement("Msg").getBytes(true);
byte[] fromBytes = msg.getMessageElement("From").getBytes(true);
String from = new String(fromBytes);
String message = new String(msgBytes);
System.out.println(message + " says " + from);
}
catch (Exception e) {
// You will notice that JXTA is not very specific with exceptions...
e.printStackTrace();
}
}
/**
* We will not find anyone if we are not regularly looking
*/
private void fetch_advertisements() {
new Thread("fetch advertisements thread") {
public void run() {
while(true) {
discovery.getRemoteAdvertisements(null, DiscoveryService.ADV, "Name", "STACK-OVERFLOW:HELLO", 1, null);
try {
sleep(10000);
}
catch(InterruptedException e) {}
}
}
}.start();
}
}
This question already has answers here:
java.rmi.NoSuchObjectException: no such object in table
(7 answers)
Closed 3 years ago.
My goal is to create a Distributed computing program that launches a server and client at the same time. I need it to be able to install on a couple of machines and have all the machines communicating with each other, i.e. Master node and 5 slave nodes all from one application.
My problem is that I cannot properly use unicastRef, I'm thinking that it is a problem with launching everything on the same port, is there a better way I am overlooking?
this is part of my code (the part that matters)
try {
RMIServer obj = new RMIServer();
obj.start(5225);
} catch (Exception e) {
e.printStackTrace();
}
try {
System.out.println("We are slave's ");
Registry rr = LocateRegistry.getRegistry("127.0.0.1", Store.PORT, new RClient());
Call ss = (Call) rr.lookup("FILLER");
System.out.println(ss.getHello());
} catch (Exception e) {
e.printStackTrace();
}
}
this is my main class (above)
this is the server class (below)
public RMIServer() {
}
public void start(int port) throws Exception {
try {
Registry registry = LocateRegistry.createRegistry(port, new RClient(), new RServer());
Call stuff = new Call();
registry.bind("FILLER", stuff);
System.out.println("Server ready");
} catch (Exception e) {
System.err.println("Server exception: " + e.toString());
e.printStackTrace();
}
}
I don't know what I am missing or what I am overlooking but the output looks like this.
Listen on 5225
Listen on 8776
Server ready
We are slave's
Listen on 8776
java.rmi.NoSuchObjectException: no such object in table
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:255)
at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:233)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:359)
at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
at Main.main(Main.java:62)
line 62 is this ::: Call ss = (Call) rr.lookup("FILLER");
Maybe it's because your reference to the stub in your server class is local to the try block and the reference is immediately garbage collected after. Try making stuff a class variable instead.