Dynamic listing binding with binding property

[eggsy84]

Hi all,

I'm wondering if anyone has a workaround or proven solution to the following problem.

I am using Spring Webflow 2.0.9 and need to perform dynamic list binding.

From the research I have initially carried out it seems that more people have raised JIRA bugs for this rather than aimed to solve it.

However I think we can be this problem.

Current I have a sample model class like so:

public class MyModelClass {
    private List<ComplexObject> complexObjects = null;

    // Gets and Sets etc etc
}

public class ComplexObject {
    private String nameOfObject = null;
    private String description = null;

    // Gets and Sets etc etc
}

Then within Web flow this can be reference like so:

<var name="myModel" class="my.package.MyModelClass" />

Then my view-state is defined like so:

<view-state id="someId" view="myTemplateView" model="myModel">
    <binder>
            <binding property="complexObjects[0].nameOfObject" />
            <binding property="complexObjects[0].description" />
    </binder>
</view>

And finally the JSP code for the fields:

<c:forEach items="${someCollection}" varStatus="loop">
    <form:input path="complexObjects[${loop.index}].nameOfObject" />
    <form:input path="complexObjects[${loop.index}].description" />
</c:forEach>

Notice I refer to complexObject[0] as the reference to my binding. However the user can specify any number of complexObjects. So I either add hundreds (I'm exaggerating of course) binding properties to cover all the user may wish to do....or come up with a better solution.

So far I have tried changing my list of complexObjects to an AutoPopulatingList like so:

public class MyModelClass {
    private AutoPopulatingList<ComplexObject> complexObjects = null;

    public MyModelClass() {
        this.complexObjects = new AutoPopulatingList<ComplexObject>(ComplexObject.class);
    }

    // Gets and Sets etc etc
}

And then change the binding property like so:

<binding property="complexObjects" />

This works for displaying the form however when the form is submitted the fields are not submitted along with the form.

Does anyone know any proven work arounds for this?

[aareshchanka]

SWF needs all objects to be serializable if you want to use them in the flow.

Try to implemet Serializable interface.

[eggsy84]

Hi there,

Thank you for the reply and taking the time to read the post. All my objects are Serializable I was aware of this but had forgot to include it on the sample code above.

[spsaran]

SWF is not supporting dynamic binding !
Submit won't fail in 2.0.9 and its bind only initialized array size and ignores the new items.
In 2.1.x, it fails while binding, it thro some EL parsing exception !

[eggsy84]

Hi there,

Thanks for the reply.

If it binds only the initial array size - for my requirements that might just be sufficient! I don't add extra form fields via Javascript or anything like that

I shall give it a test.

[eggsy84]

Hi all,

I have solved my issue because I knew the size of the collection before the state was entered.

However for those looking at Dynamic list sizes such as adding fields with Javascript, I have found a bug report on the Spring Webflow JIRA

https://jira.springframework.org/browse/SWF-1065

The reporter has included a patch which may help people.

Eggsy