Re: [Ikvm-developers] System.NullReferenceException while using java bean Introspector with java.lang.string data type

[Jeroen F. <je...@su...>]

If you get a System.NullReferenceException on "setMethod.invoke(wekaInstance, values);", your either running into a bug in IKVM's reflection or setMethod is null. Are you sure the property is writeable?

If setMethod isn't null, can you build a repro (as small as possible) and send it to me (off list)?

Regards,
Jeroen

> -----Original Message-----
> From: abiratsis [mailto:ale...@gm...]
> Sent: Sunday, March 22, 2009 11:14
> To: ikv...@li...
> Subject: [Ikvm-developers] System.NullReferenceException while using
> java bean Introspector with java.lang.string data type
> 
> 
> Hello guys, I am using weka libraries with .net via IKVM. The following
> code sets the properties of a weka java Bean by using Java Bean
> Introspector. I have a problem with strings though, in the case that
> the Bean property is of type java.lang.String I am getting a
> System.NullReference exception while calling method.invoke method. I
> have also found that it happens only for a specific (revision  called)
> property.
> 
> Here is my code:
> 
> public static java.lang.Object BindWekaModuleOptions(WekaModule module,
> List<WekaModuleParameter> options)
>         {
>             java.lang.Object wekaInstance = module.JavaWekaObjectPntr
> == null ? GetWekaModuleFromName(module, null):
> module.JavaWekaObjectPntr;
> 
>             BeanInfo info =
> Introspector.getBeanInfo(wekaInstance.getClass());//configure Bean
> Introspector for the given class instance
> 
>             //iterate through Bean properties
>             foreach (PropertyDescriptor descr in
> info.getPropertyDescriptors())
>             {
>                 Type ctype =
> WekaModuleParameter.ConvertWekaOptionType(descr.getPropertyType().toStr
> ing());
>                 if (ctype == null) continue;
> 
>                 WekaModuleParameter foundOption = options.Find(mod =>
> mod.Name == descr.getName());
> 
>                 if (foundOption != null)
>                 {
>                     Method setMethod = descr.getWriteMethod();
>                     object[] values = new object[1];
> 
>                     switch (foundOption.DataType.ToString())
>                     {
>                         case "System.Double":
>                             values[0] =
> java.lang.Double.valueOf(Convert.ToDouble(foundOption.ParamValue).ToStr
> ing(new
> CultureInfo("en-US")));
>                             break;
>                         case "System.Single":
>                             values[0] =
> java.lang.Float.valueOf(Convert.ToSingle(foundOption.ParamValue).ToStri
> ng(new
> CultureInfo("en-US")));
>                             break;
>                         case "System.Float":
>                             values[0] =
> java.lang.Float.valueOf(Convert.ToSingle(foundOption.ParamValue).ToStri
> ng(new
> CultureInfo("en-US")));
>                             break;
>                         case "System.Int32":
>                             values[0] =
> java.lang.Integer.valueOf(foundOption.ParamValue.ToString());
>                             break;
>                         case "System.Boolean":
>                             values[0] =
> java.lang.Boolean.valueOf(foundOption.ParamValue.ToString());
>                             break;
>                         case "System.String":
>                             values[0] =
> java.lang.String.valueOf(foundOption.ParamValue);
>                             break;
>                         default:
>                             values[0] =
> java.lang.String.valueOf(foundOption.ParamValue);
>                             break;
>                     }
> 
>                     try
>                     {
>                         setMethod.invoke(wekaInstance, values);
>                     }
>                     catch (Exception ex)
>                     {
>                         string msg = ex.Message;
>                     }
>                 }
>             }
> 
>             return wekaInstance;
>         }
> 
> Does anyone has face any similar problem guys?
> 
> Thanx a lot
> --
> View this message in context:
> http://www.nabble.com/System.NullReferenceException-while-using-java-
> bean-Introspector-with-java.lang.string-data-type-
> tp22644670p22644670.html
> Sent from the IKVM .NET - Dev mailing list archive at Nabble.com.
> 
> 
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