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Observing EList size [message #485437]

Fri, 11 September 2009 17:40

Pierre Francis Roy

Messages: 12
Registered: July 2009

Junior Member

Dear,

I have the following code used for observing EMF object attributes for
binding with table TableViewer columns.

IObservableMap[] map = new IObservableMap[3];
map[0] =
EMFProperties.value(DairyStudioQualityPackage.Literals.SAMPL E_SET__DATE_CREATION).observeDetail(set);
map[1] =
EMFProperties.value(DairyStudioQualityPackage.Literals.SAMPL E_SET__TYPE).observeDetail(set);
map[2] =
EMFProperties.value(DairyStudioQualityPackage.Literals.SAMPL E_SET__SAMPLES).observeDetail(set);

In the third properties I'm currently observing an EList<Sample> object.
In this case what I want to do is to observ the size of that EList
(EList.size()).

Any idea how this can be done?

Thanks for helping me getting a good start with databinding.

Pierre Francis

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Re: Observing EList size [message #485441 is a reply to message #485437]

Fri, 11 September 2009 17:54

Ed Merks

Messages: 33136
Registered: July 2009

Senior Member

Pierre,

Comments below.

Pierre Francis Roy wrote:
> Dear,
>
> I have the following code used for observing EMF object attributes for
> binding with table TableViewer columns.
>
> IObservableMap[] map = new IObservableMap[3];
> map[0] =
> EMFProperties.value(DairyStudioQualityPackage.Literals.SAMPL E_SET__DATE_CREATION).observeDetail(set);
>
> map[1] =
> EMFProperties.value(DairyStudioQualityPackage.Literals.SAMPL E_SET__TYPE).observeDetail(set);
>
> map[2] =
> EMFProperties.value(DairyStudioQualityPackage.Literals.SAMPL E_SET__SAMPLES).observeDetail(set);
>
>
> In the third properties I'm currently observing an EList<Sample>
> object. In this case what I want to do is to observ the size of that
> EList (EList.size()).
> Any idea how this can be done?
In terms of notifications, EMF produces notifications for all things
that affect the list so there's certainly enough information to know
when to check the size. In particular, add and remove notifications
will affect the size.
>
> Thanks for helping me getting a good start with databinding.
I'm not sure how you'd hook data binding up for that though.
>
> Pierre Francis
>

Ed Merks
Professional Support: https://www.macromodeling.com/

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Re: Observing EList size [message #485482 is a reply to message #485437]

Fri, 11 September 2009 21:49

Matthew Hall

Messages: 368
Registered: July 2009

Senior Member

Pierre Francis Roy wrote:
> In this case what I want to do is to observ the size of that EList
> (EList.size()).

If there is an EStructuralFeature for EList.size() somewhere then you
could observe it using:
EMFProperties.value(eListSizeStructuralFeature).observe(eLis t)

Otherwise you can write a custom IValueProperty:

class NotifyingListSizeProperty extends SimpleValueProperty {
protected Object doGetValue(Object source) {
return ((NotifyingList)source).size();
}

protected void doSetValue(Object source, Object value) {
throw new UnsupportedOperationException(
toString() + " is unmodifiable");
}

public INativePropertyListener adaptListener(
ISimplePropertyListener listener) {
return new Listener(listener);
}

private class Listener extends AdapterImpl
implements INativePropertyListener {
ISimplePropertyListener delegate;

public Listener(ISimplePropertyListener delegate) {
this.delegate = delegate;
}

public void addTo(Object source) {
if (source != null)
((Notifier) ((NotifyingList)source).getNotifier())
.eAdapters().add(this);
}

public void removeFrom(Object source) {
if (source != null)
((Notifier) ((NotifyingList)source).getNotifier())
.eAdapters().remove(this);
}

public void notifyChanged(Notification msg) {
delegate.handleEvent(new SimplePropertyEvent(
SimplePropertyEvent.CHANGE,
msg.getNotifier(),
NotifyingListenerProperty.this,
null);
}
}

public String toString() { return "EList.size <int>"; }
}

With this property you can basically do the same the first example code:

IObservableValue listSize =
new NotifyingListSizeProperty().observe(eList);

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Re: Observing EList size [message #485490 is a reply to message #485482]

Sat, 12 September 2009 00:23

Thomas Schindl

Messages: 6651
Registered: July 2009

Senior Member

Matthew Hall schrieb:
> Pierre Francis Roy wrote:
>> In this case what I want to do is to observ the size of that EList
>> (EList.size()).
>
> If there is an EStructuralFeature for EList.size() somewhere then you
> could observe it using:
> EMFProperties.value(eListSizeStructuralFeature).observe(eLis t)

There isn't one :-(

>
> Otherwise you can write a custom IValueProperty:
>
> class NotifyingListSizeProperty extends SimpleValueProperty {
> protected Object doGetValue(Object source) {
> return ((NotifyingList)source).size();
> }
>
> protected void doSetValue(Object source, Object value) {
> throw new UnsupportedOperationException(
> toString() + " is unmodifiable");
> }
>
> public INativePropertyListener adaptListener(
> ISimplePropertyListener listener) {
> return new Listener(listener);
> }
>
> private class Listener extends AdapterImpl
> implements INativePropertyListener {
> ISimplePropertyListener delegate;
>
> public Listener(ISimplePropertyListener delegate) {
> this.delegate = delegate;
> }
>
> public void addTo(Object source) {
> if (source != null)
> ((Notifier) ((NotifyingList)source).getNotifier())
> .eAdapters().add(this);
> }
>
> public void removeFrom(Object source) {
> if (source != null)
> ((Notifier) ((NotifyingList)source).getNotifier())
> .eAdapters().remove(this);
> }
>
> public void notifyChanged(Notification msg) {
> delegate.handleEvent(new SimplePropertyEvent(
> SimplePropertyEvent.CHANGE,
> msg.getNotifier(),
> NotifyingListenerProperty.this,
> null);
> }
> }
>
> public String toString() { return "EList.size <int>"; }
> }
>
> With this property you can basically do the same the first example code:
>
> IObservableValue listSize =
> new NotifyingListSizeProperty().observe(eList);

Might make sense to add it to our library would you file a bug Matt and
attach your source from above?

Tom

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Re: Observing EList size [message #485495 is a reply to message #485490]

Sat, 12 September 2009 04:51

Matthew Hall

Messages: 368
Registered: July 2009

Senior Member

> Might make sense to add it to our library would you file a bug Matt and
> attach your source from above?

Sure, but I'm not sure which product/component to attach it to.

Matthew

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Re: Observing EList size [message #485505 is a reply to message #485495]

Sat, 12 September 2009 07:12

Pierre Francis Roy

Messages: 12
Registered: July 2009

Junior Member

Dear Tom and Matthew,

Thanks for your interest in that problem. I think my situation is quite
current. It applies in the case when you want to display the number of
elements in master object in a master/details situation.

The solution of Matthew seem to me quite conveniant except for the fact
that I'm not quite sure how to get an IObservableMap from that example
instead of an IObservableValue.

Required by your solution:
IObservableValue listSize = new
NotifyingListSizeProperty().observe(eList);

Required in my situation
IObservableMap[] map = new IObservableMap[3];
...
IEMFValueProperty prop =
EMFProperties.value(DairyStudioQualityPackage.Literals.SAMPL E_SET__SAMPLES);
??? map[2] = new NotifyingListSizeProperty().observe(prop); ???

Thanks a lot guys

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Re: Observing EList size [message #485508 is a reply to message #485495]

Sat, 12 September 2009 09:53

Thomas Schindl

Messages: 6651
Registered: July 2009

Senior Member

Hi Matt,

https://bugs.eclipse.org/bugs/enter_bug.cgi?product=EMF& component=Edit&version=2.5.0&bug_severity=enhancemen t&rep_platform=All&op_sys=All&short_desc=[Databinding]

Thanks

Tom

@Ed: Could we add the databinding bundles to the description of EMF-Edit
component shown in bugzilla?

Matthew Hall schrieb:
>> Might make sense to add it to our library would you file a bug Matt and
>> attach your source from above?
>
> Sure, but I'm not sure which product/component to attach it to.
>
> Matthew

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Re: Observing EList size [message #485696 is a reply to message #485505]

Mon, 14 September 2009 14:20

Matthew Hall

Messages: 368
Registered: July 2009

Senior Member

Pierre Francis Roy wrote:
> Required in my situation
> IObservableMap[] map = new IObservableMap[3];
> ..
> IEMFValueProperty prop =
> EMFProperties.value(DairyStudioQualityPackage.Literals.SAMPL E_SET__SAMPLES);
>
> ??? map[2] = new NotifyingListSizeProperty().observe(prop); ???

You can make a nested property as follows:

IEMFValueProperty eListSizeProp = EMFProperties
.value(DairyStudioQualityPackage.Literals.SAMPLE_SET__SAMPLE S)
.value(new NotifyingListSizeProperty());

Assuming you are binding this property to a JFace viewer, your code
would be something like:

IObservableSet knownElements =
observableListContentProvider.getKnownElements();
map[2] = eListSizeProperty.observeDetail(knownElements);

I've also been thinking that we should provide a property reducer method
for collection properties:

interface IListProperty {
+ public IValueProperty reduce(IValueProperty)
}

interface ISetProperty {
+ public IValueProperty reduce(IValueProperty)
}

interface IMapProperty {
+ public IValueProperty reduce(IValueProperty)
}

This way we could just provide a generic property Properties.size(), thus:

IValueProperty listSizeProp = EMFProperties
.list(DairyStudioQualityPackage.Literals.SAMPLE_SET__SAMPLES )
.reduce(Properties.size());

We could also include several generic reducer properties like average,
median, sum, min, max, etc. What do you think?

Matthew

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Re: Observing EList size [message #485700 is a reply to message #485508]

Mon, 14 September 2009 14:26

Matthew Hall

Messages: 368
Registered: July 2009

Senior Member

Filed https://bugs.eclipse.org/bugs/show_bug.cgi?id=289353

Matthew

Tom Schindl wrote:
> Hi Matt,
>
> https://bugs.eclipse.org/bugs/enter_bug.cgi?product=EMF& component=Edit&version=2.5.0&bug_severity=enhancemen t&rep_platform=All&op_sys=All&short_desc=[Databinding]
>
> Thanks
>
> Tom
>
> @Ed: Could we add the databinding bundles to the description of EMF-Edit
> component shown in bugzilla?
>
> Matthew Hall schrieb:
>>> Might make sense to add it to our library would you file a bug Matt and
>>> attach your source from above?
>> Sure, but I'm not sure which product/component to attach it to.
>>
>> Matthew

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