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I need to invoke a GWT RPC service from simple Java code. Yes, I read this

Invoke a GWT RPC service from Java directly

However, my issue is that I do not have access to the web application code (though I could ask and obtain some parts of it), so I cannot just add it to the build path of my Java project. All the info I read from the internet is not clear on what exactly needs to be imported. The question is: what is the minumum that I should include in my project in order to make the call to the service work (using syncproxy gwt for example)? Will it be enough to redefine the client interfaces inside my code or should I do some compiling work as well?

EDIT: I've done some testing locally with the default web app running on localhost. I created a new java project, imported the sync and async service interfaces and the RPC serialization policy I found in the WAR folder of the web app. This is my testing code

import com.gdevelop.gwt.syncrpc.SyncProxy;

public class serviceCall {

private static final String MODULE_BASE_URL = "http://127.0.0.1:8888/gwttestapp/";
private static final String SERVICE_NAME = "greet";

public static void main(String[] args) {

     GreetingService rpcService = (GreetingService) SyncProxy.newProxyInstance(GreetingService.class, MODULE_BASE_URL, SERVICE_NAME, "CB32CC2E454EE7E1088B2E29CEB44F84");
     String result = rpcService.greetServer("SyncProxy");
}
}

However the server seems not to recognize the RPC policy, since I get the following exception:

Exception in thread "main" com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException: This application is out of date, please click the refresh button on your browser. ( Blocked attempt to access interface 'GreetingService', which is not implemented by 'com.apptesting.server.GreetingServiceImpl'; this is either misconfiguration or a hack attempt )
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
at com.gdevelop.gwt.syncrpc.SyncClientSerializationStreamReader.instantiate(SyncClientSerializationStreamReader.java:746)
at com.gdevelop.gwt.syncrpc.SyncClientSerializationStreamReader.deserialize(SyncClientSerializationStreamReader.java:816)
at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.readObject(AbstractSerializationStreamReader.java:119)
at com.gdevelop.gwt.syncrpc.RemoteServiceSyncProxy.doInvoke(RemoteServiceSyncProxy.java:204)
at com.gdevelop.gwt.syncrpc.RemoteServiceInvocationHandler.invoke(RemoteServiceInvocationHandler.java:193)
at com.sun.proxy.$Proxy0.greetServer(Unknown Source)
at serviceCall.main(serviceCall.java:11)

Anybody can help?

Community
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splinter123
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1 Answers1

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Try initiating the rpcService without the .gwt.rpc policy specified. IE, just make the call:

GreetingService rpcService = (GreetingService) SyncProxy.newProxyInstance(GreetingService.class, MODULE_BASE_URL, SERVICE_NAME);

You generally do not need to specify the exact serialization policy as the RPC system should automatically figure it out. In fact, it's better not to specify it because the deployed site will change the serialization policy file as the back-end changes. Take a look at the source and testing wiki (https://code.google.com/p/gwt-syncproxy/wiki/SourceAndTesting) for some guidance on on setup need needs. The source code for the Android testing app may provide you some code guidance on creating a functional standalone (if you ignore the AsyncCallback implementations)

In general answer to your question, for deployment purposes, all you really are the interfaces you specified (*Service & *ServiceAsync). For testing purposes in your development environment, you can mock some *Impl files that will provide you some generic responses for testing (such as in the default web-app). Take a look at the Android Wiki in the sync-proxy project (https://code.google.com/p/gwt-syncproxy/wiki/Android) at the setup section for a quick overview on linking the needed files.

Disclaimer: I'm a developer for the Android syncproxy library

JCricket
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