Re: BeansWrapper.populateClassMapWithPropertyDescriptor failing to create property descriptors

Actually, I don't think we use write methods at all, do we? FreeMarker is only ever reading properties, never writing them. I'm not even sure why I wrote the code so that it's putting the write methods into the property descriptors; I guess we could just replace them with nulls and thus emulate read-only properties.

Attila.

On Nov 15, 2011, at 7:26 AM, Donnchadh Ó Donnabháin wrote:

>  Hi guys,
> 
> This isn't a huge issue for us at the moment but it generates an ugly
> warning and prevents us from using certain properties in our
> FreeMarker.
> 
> Some of our domain model classes use generics, with some accessor
> methods using type parameters. The java compiler generates bridge
> methods in subclasses of our generic classes and these bridge methods
> have a return type that doesn't match the setter in the parent class,
> resulting in the following exception:
> 
> 
> WARN beans:116 - Failed creating a publicly-accessible property
> descriptor for  ...
> java.beans.IntrospectionException: type mismatch between read and write methods
>       at java.beans.PropertyDescriptor.findPropertyType(PropertyDescriptor.java:603)
>       at java.beans.PropertyDescriptor.setWriteMethod(PropertyDescriptor.java:270)
>       at java.beans.PropertyDescriptor.<init>(PropertyDescriptor.java:117)
>       at freemarker.ext.beans.BeansWrapper.populateClassMapWithPropertyDescriptor(BeansWrapper.java:1255)
>       at freemarker.ext.beans.BeansWrapper.populateClassMapWithBeanInfo(BeansWrapper.java:1152)
>       at freemarker.ext.beans.BeansWrapper.populateClassMap(BeansWrapper.java:1072)
>       at freemarker.ext.beans.BeansWrapper.introspectClassInternal(BeansWrapper.java:1010)
>       at freemarker.ext.beans.BeansWrapper.introspectClass(BeansWrapper.java:969)
>       at freemarker.ext.beans.BeanModel.<init>(BeanModel.java:140)
>       at freemarker.ext.beans.StringModel.<init>(StringModel.java:90)
>       at freemarker.ext.beans.StringModel$1.create(StringModel.java:75)
>       at freemarker.ext.beans.BeansModelCache.create(BeansModelCache.java:45)
>       at freemarker.ext.util.ModelCache.getInstance(ModelCache.java:115)
>       at freemarker.ext.beans.BeansWrapper.wrap(BeansWrapper.java:468)
>       at freemarker.template.DefaultObjectWrapper.handleUnknownType(DefaultObjectWrapper.java:144)
>       at freemarker.template.DefaultObjectWrapper.wrap(DefaultObjectWrapper.java:128)
>       at freemarker.template.WrappingTemplateModel.wrap(WrappingTemplateModel.java:134)
>       at freemarker.template.SimpleHash.get(SimpleHash.java:224)
> 
> 
> Maybe this code on line 1255 of BeansWrapper.java (FreeMarker 2.3.17):
>                        pd = new PropertyDescriptor(pd.getName(),
>                                publicReadMethod, pd.getWriteMethod());
> 
> could be replaced with something like this:
> 
>                        Method writeMethod = pd.getWriteMethod();
>                        if (writeMethod != null &&
> (pd.getWriteMethod().getParameterTypes().length != 1
>                                ||
> pd.getWriteMethod().getParameterTypes()[0] !=
> publicReadMethod.getReturnType())) {
>                            writeMethod = null;
>                        }
>                        pd = new PropertyDescriptor(pd.getName(),
>                                publicReadMethod, writeMethod);
> 
> What do you think?
> 
>    Donnchadh
> 
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