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| [DataBinding] JavaBeansObservable not updating [message #325566] |
Fri, 22 February 2008 03:37  |
Eclipse User |
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Hello,
during development with the databinding framework I found a strange
behaviour of the JavaBeansObservable (M20070822-0800):
Suppose we run the following simple code:
ModelBean modelBean = new ModelBean();
ModelBean targetBean = new ModelBean();
IObservableList modelBeanObservableList =
BeansObservables.observeList(Realm.getDefault(), modelBean, "list",
String.class);
IObservableList targetBeanObservableList =
BeansObservables.observeList(Realm.getDefault(), targetBean, "list",
String.class);
DataBindingContext bindingContext = new DataBindingContext();
bindingContext.bindList(targetBeanObservableList, modelBeanObservableList,
null, null);
modelBean.add("Str 1");
modelBean.clear();
targetBean.add("Str 2");
for(Object o : modelBean.getList()){
System.out.println(o);
}
ModelBean has a simple array list containing strings and clear() resets the
list. Any other modification of the list can be imagined.
One would expect the console to output: "Str2". But surprisingly there is no
output at all - the model was not updated.
When I debugged the code of JavaBeansObservable I found out the place, where
the underlying writeableList is updated:
public void add(int index, Object element) {
....
wrappedList.add(index, element);
....
}
But this line throws an exception (UnsupportedOperationException?) as
wrappedList is not of type ArrayList but Arrays$ArrayList.
I question myself, what did I wrong?
Nice Greetings,
Masroor
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| Re: [DataBinding] JavaBeansObservable not updating [message #325579 is a reply to message #325566] |
Fri, 22 February 2008 10:38  |
| Eclipse User |
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Arrays.asList returns a list that is *backed* by the passed in array.
Since arrays cannot change length, neither can the list. To make the
list fully modifiable, try using an ArrayList with the copy constructor:
list = new ArrayList(Arrays.asList(array));
Matthew
Masroor Ahmad wrote:
> Hello,
> during development with the databinding framework I found a strange
> behaviour of the JavaBeansObservable (M20070822-0800):
>
> Suppose we run the following simple code:
>
> ModelBean modelBean = new ModelBean();
> ModelBean targetBean = new ModelBean();
>
> IObservableList modelBeanObservableList =
> BeansObservables.observeList(Realm.getDefault(), modelBean, "list",
> String.class);
> IObservableList targetBeanObservableList =
> BeansObservables.observeList(Realm.getDefault(), targetBean, "list",
> String.class);
>
> DataBindingContext bindingContext = new DataBindingContext();
> bindingContext.bindList(targetBeanObservableList, modelBeanObservableList,
> null, null);
>
> modelBean.add("Str 1");
> modelBean.clear();
> targetBean.add("Str 2");
> for(Object o : modelBean.getList()){
> System.out.println(o);
> }
>
> ModelBean has a simple array list containing strings and clear() resets the
> list. Any other modification of the list can be imagined.
> One would expect the console to output: "Str2". But surprisingly there is no
> output at all - the model was not updated.
> When I debugged the code of JavaBeansObservable I found out the place, where
> the underlying writeableList is updated:
>
> public void add(int index, Object element) {
> ...
> wrappedList.add(index, element);
> ...
> }
>
> But this line throws an exception (UnsupportedOperationException?) as
> wrappedList is not of type ArrayList but Arrays$ArrayList.
>
> I question myself, what did I wrong?
>
> Nice Greetings,
> Masroor
>
>
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| Re: [DataBinding] JavaBeansObservable not updating [message #325581 is a reply to message #325579] |
Fri, 22 February 2008 11:11 |
| Eclipse User |
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Thanks for the reply.
I see, to solve this one has to change API code or subclass.
The original API code:
public class JavaBeanObservableList extends ObservableList implements
IBeanObservable {
....
updateWrappedList(Arrays.asList(getValues()));
....
}
Regards,
Masroor
> Arrays.asList returns a list that is *backed* by the passed in array.
> Since arrays cannot change length, neither can the list. To make the list
> fully modifiable, try using an ArrayList with the copy constructor:
>
> list = new ArrayList(Arrays.asList(array));
>
> Matthew
>
> Masroor Ahmad wrote:
>> Hello,
>> during development with the databinding framework I found a strange
>> behaviour of the JavaBeansObservable (M20070822-0800):
>>
>> Suppose we run the following simple code:
>>
>> ModelBean modelBean = new ModelBean();
>> ModelBean targetBean = new ModelBean();
>>
>> IObservableList modelBeanObservableList =
>> BeansObservables.observeList(Realm.getDefault(), modelBean, "list",
>> String.class);
>> IObservableList targetBeanObservableList =
>> BeansObservables.observeList(Realm.getDefault(), targetBean, "list",
>> String.class);
>>
>> DataBindingContext bindingContext = new DataBindingContext();
>> bindingContext.bindList(targetBeanObservableList,
>> modelBeanObservableList, null, null);
>>
>> modelBean.add("Str 1");
>> modelBean.clear();
>> targetBean.add("Str 2");
>> for(Object o : modelBean.getList()){
>> System.out.println(o);
>> }
>>
>> ModelBean has a simple array list containing strings and clear() resets
>> the list. Any other modification of the list can be imagined.
>> One would expect the console to output: "Str2". But surprisingly there is
>> no output at all - the model was not updated.
>> When I debugged the code of JavaBeansObservable I found out the place,
>> where the underlying writeableList is updated:
>>
>> public void add(int index, Object element) {
>> ...
>> wrappedList.add(index, element);
>> ...
>> }
>>
>> But this line throws an exception (UnsupportedOperationException?) as
>> wrappedList is not of type ArrayList but Arrays$ArrayList.
>>
>> I question myself, what did I wrong?
>>
>> Nice Greetings,
>> Masroor
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| Re: [DataBinding] JavaBeansObservable not updating [message #325588 is a reply to message #325585] |
Fri, 22 February 2008 12:09 |
| Eclipse User |
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The current version of DataBinding is compatible with Eclipse 3.3. Try
running your app with a recent build of JDB:
http://download.eclipse.org/eclipse/downloads/drops/S-3.4M5- 200802071530/index.php
You should only need to swap in the data binding plugins:
org.eclipse.core.databinding
org.eclipse.core.databinding.beans
org.eclipse.jface.databinding
If the error goes away with the 3.4 build, we'll still want to fix it in
the 3.3 maintenance stream. So please file a bug either way--this test
will just help us determine the scope of the bug.
Matthew
Masroor Ahmad wrote:
> 1.0.1.M20070910-0800b
>
> "Matthew Hall" <matthall@woodcraftmill.com> schrieb im Newsbeitrag
> news:fpmt68$t5s$1@build.eclipse.org...
>> I think this was fixed some time ago, possibly after the 3.3 release. What
>> version of DataBinding are you using?
>>
>> Matthew
>>
>> Masroor Ahmad wrote:
>>> Roger this. It's the latter case.
>>> Masroor
>>>
>>> "Boris Bokowski" <Boris_Bokowski@ca.ibm.com> schrieb im Newsbeitrag
>>> news:fpmqng$fe3$1@build.eclipse.org...
>>>>> But this line throws an exception (UnsupportedOperationException?) as
>>>>> wrappedList is not of type ArrayList but Arrays$ArrayList.
>>>> Arrays.asList() returns an unmodifiable list. The question now is: did
>>>> you create this list, or did the data binding framework do that. If it's
>>>> the former, make sure you use modifiable lists in both model and target.
>>>> If it's the latter, would you mind filing a bug, ideally with an
>>>> attached snippet with which we can reproduce it?
>>>>
>>>> http://wiki.eclipse.org/Platform_UI/FAQ#How_do_I_report_a_bu g.3F
>>>>
>>>> Thanks
>>>> Boris
>>>>
>>>>
>
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