Generics, JSNI and Integer problem

[stole]

I have declared the following class:

public class JsniTest<T> {

    private Map<T, String> map;

    public JsniTest(Map<T, String> map) {

        this.map = map;

    }

    public String get(T rowKey) {

        return map.get(rowKey);

    }

}

 

and the following "main" class:

public class TheApp implements EntryPoint {

  public void onModuleLoad() {

    final Map<Integer, String> map = new HashMap<Integer, String>();

    map.put(0, "test");

    final JsniTest<Integer> test = new JsniTest<Integer>(map);

    final String result = testJsni(test, 0);

    l.info("testJsni:" + result);

  }

  public native String testJsni(JsniTest x, int key) /*-{

      return x.@com.test.client.JsniTest::get(Ljava/lang/Object;)(key);

  }-*/;

}

When I run this code on Gwt 2.5.1 in debug mode I get the following exception:

SEVERE: invoke arguments: JS value of type number, expected java.lang.Object

java.lang.IllegalArgumentException: invoke arguments: JS value of type number, expected java.lang.Object

    at com.google.gwt.dev.shell.JsValueGlue.get(JsValueGlue.java:178)

    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:65)

    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)

    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:338)

    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:219)

    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)

    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:571)

    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:279)

    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)

Is it possible to invoke the get method of JsniTest and receive the proper result? What are my options? The JsniTest class is just a replacement for the real class I need to use, over which I have no control as it is a third party library class. I could possibly wrap it with a wrapper class that would work for any T. I have full control over TheApp class and the testJsni method. Thanks for your help.

[Thomas Broyer]

You need to wrap your int into a java.lang.Integer using its valueOf or new(). JSNI doesn't do auto-boxing/unboxing.

[stole]

Thank you very much for your help. This, indeed, solved the problem.