Sending messages in GWT by Errai
Hi, http://docs.jboss.org/errai/latest/errai/reference/html_single/#sid-5931280_MessagingAPIBasics-SendingMessageswiththeClientBus here is how to send a message from client.
I have a client HelloServer.java, when i click on the button I want to send message to a server.
package gwt.user.client;
import org.jboss.errai.bus.client.ErraiBus;
import org.jboss.errai.bus.client.api.base.CommandMessage;
import org.jboss.errai.bus.client.api.base.MessageBuilder;
import org.jboss.errai.bus.client.api.messaging.Message;
import org.jboss.errai.bus.client.api.messaging.MessageBus;
import org.jboss.errai.bus.client.api.messaging.MessageCallback;
import org.jboss.errai.bus.client.api.messaging.RequestDispatcher;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.user.client.rpc.ServiceDefTarget;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.DialogBox;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.VerticalPanel;
public class HelloServer implements EntryPoint{
private MyTable table;
private MessageBus bus = ErraiBus.get();
private RequestDispatcher dispatcher = ErraiBus.getDispatcher();
UserService usrSer;
private RequestDispatcher getDispatcher(){
return this.dispatcher;
}
public void onModuleLoad() {
table = new MyTable(null);
Button button = new Button("Click me");
// We can add style names
button.addStyleName("pc-template-btn");
// or we can set an id on a specific element for styling
VerticalPanel vPanel = new VerticalPanel();
vPanel.setWidth("100%");
vPanel.setHorizontalAlignment(VerticalPanel.ALIGN_CENTER);
vPanel.add(button);
vPanel.add(table);
// add table and button to the RootPanel
RootPanel.get().add(vPanel);
// create the dialog box
final DialogBox dialogBox = new DialogBox();
dialogBox.setText("Welcome to GWT Server Communication!");
dialogBox.setAnimationEnabled(true);
Button closeButton = new Button("close");
VerticalPanel dialogVPanel = new VerticalPanel();
dialogVPanel.setWidth("100%");
dialogVPanel.setHorizontalAlignment(VerticalPanel.ALIGN_CENTER);
dialogVPanel.add(closeButton);
closeButton.addClickHandler(new ClickHandler() {
@Override
public void onClick(ClickEvent event) {
dialogBox.hide();
}
});
// Set the contents of the Widget
dialogBox.setWidget(dialogVPanel);
button.addClickHandler(new ClickHandler() {
@Override
public void onClick(ClickEvent event) {
UserServiceAsync service = (UserServiceAsync) GWT.create(UserService.class);
ServiceDefTarget serviceDef = (ServiceDefTarget) service;
serviceDef.setServiceEntryPoint(GWT.getModuleBaseURL() + "userService");
UserCallback myUserCallback = new UserCallback(table);
MessageBuilder.createMessage()
.toSubject("UserServiceImpl") // (1)
.signalling() // (2)
.noErrorHandling() // (3)
.sendNowWith(getDispatcher()); // (4)
service.getUserList(myUserCallback);
}
});
}
}
UserServiceImpl.java is the server where I want to receive the message in callback method.
package gwt.user.server;
import gwt.user.client.User;
import gwt.user.client.UserService;
import java.util.ArrayList;
import java.util.List;
import org.jboss.errai.bus.client.api.base.CommandMessage;
import org.jboss.errai.bus.client.api.messaging.Message;
import org.jboss.errai.bus.client.api.messaging.MessageCallback;
import org.jboss.errai.bus.server.annotations.Service;
import com.google.gwt.user.server.rpc.RemoteServiceServlet;
@Service
public class UserServiceImpl extends RemoteServiceServlet implements UserService, MessageCallback {
private static final long serialVersionUID = 1L;
private List<User> userList = new ArrayList<User>();
public UserServiceImpl() {
User user = new User();
user.setId("1");
user.setUsername("Peter");
user.setNumberOfHits("15");
userList.add(user);
user = new User();
user.setId("2");
user.setUsername("Hanz");
user.setNumberOfHits("25");
userList.add(user);
}
public User getUser(String id) {
for (Object object : userList) {
if (((User) object).getId().equals(id))
return ((User) object);
}
return null;
}
public List<User> getUserList() {
return userList;
}
@Override
public void callback(Message message) {
System.out.print("Message received");
}
public void callback(CommandMessage message) {
System.out.print("Message received");
}
}
When I click the button I get no subscribers to deliver error message:
org.jboss.errai.bus.client.api.base.NoSubscribersToDeliverTo: no subscribers to deliver to for subject: UserServiceImpl
org.jboss.errai.bus.client.framework.ClientMessageBusImpl.send(ClientMessageBusImpl.java:812)
org.jboss.errai.bus.client.ErraiBus$3.dispatch(ErraiBus.java:171)
org.jboss.errai.bus.client.api.base.CommandMessage.sendNowWith(CommandMessage.java:349)
org.jboss.errai.bus.client.api.base.DefaultMessageBuilder$1.sendNowWith(DefaultMessageBuilder.java:95)
gwt.user.client.HelloServer$2.onClick(HelloServer.java:84)
If I annotate UserServiceImpl.java class with
@Service("UserServiceImpl")
it doesn't help and I get the same error.
When I add
bus.subscribe("UserServiceImpl", new UserServiceImpl());
before
MessageBuilder.createMessage()
method in HelloServer.java
I get error message:
[ERROR] No source code is available for type gwt.user.server.UserServiceImpl; did you forget to inherit a required module?
http://stackoverflow.com/questions/29827445/sending-messages-in-gwt-by-errai-framework
