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Remove item from list using its containment Setting [message #1795708]

Thu, 27 September 2018 08:12

Erdal Karaca

Messages: 853
Registered: July 2009

Senior Member

I have a containment list that I need to remove an element from.
My idea was to get the element's Setting and use that to remove it from its containment list, but calling setting.unset() will clear the whole list.

        MyContainer container = fcn.getRequirementsFolder();
        MyElement element = container.getElements().get(0);
        EStructuralFeature feature = element.eContainmentFeature();
        Setting setting = ((InternalEObject)container).eSetting(feature);
        setting.unset(); // <- this will clear the list: How to remove just the element?

Is there a way to remove just the element using the setting?

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Re: Remove item from list using its containment Setting [message #1795712 is a reply to message #1795708]

Thu, 27 September 2018 08:40

Ed Willink

Messages: 6396
Registered: July 2009

Senior Member

Hi

It is probably possible to use the Setting, but that seems like a really hard way to go.

If you know that the container feature is named "requirementsFolder" then setRequirementsFolder(null) should work.

If you also know that the containment feature is named "elements" then getRequirementsFolder().getElements().remove(this) should work.

If you only know that the containment feature is a collection then something like ((List)eContainer().eGet(eContainmentFeature())).remove(this) should work.

If you don't know whether the container is a list or an object you will need to do an isMany() conditionalization.

The Impl API offers other alternatives that I have never tried such as eBasicRemoveFromContainerFeature that should be studied carefully before use.

Regards

Ed Willink

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Re: Remove item from list using its containment Setting [message #1795713 is a reply to message #1795712]

Thu, 27 September 2018 08:53

Erdal Karaca

Messages: 853
Registered: July 2009

Senior Member

Thanks, Ed!

I do not know if the container is a list or an object (example was just to demo the use case). Would be convenient to use the setting without checking if the feature is many and casting to Collection (I have used that pattern already lots of times).

Ed Willink wrote on Thu, 27 September 2018 10:40

Hi

It is probably possible to use the Setting, but that seems like a really hard way to go.

If you know that the container feature is named "requirementsFolder" then setRequirementsFolder(null) should work.

If you also know that the containment feature is named "elements" then getRequirementsFolder().getElements().remove(this) should work.

If you only know that the containment feature is a collection then something like ((List)eContainer().eGet(eContainmentFeature())).remove(this) should work.

If you don't know whether the container is a list or an object you will need to do an isMany() conditionalization.

The Impl API offers other alternatives that I have never tried such as eBasicRemoveFromContainerFeature that should be studied carefully before use.

Regards

Ed Willink

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Re: Remove item from list using its containment Setting [message #1795726 is a reply to message #1795713]

Thu, 27 September 2018 10:35

Ed Merks

Messages: 30230
Registered: July 2009

Senior Member

You can use org.eclipse.emf.ecore.util.EcoreUtil.remove(EObject) to remove an object from its container; this will remove it from its resource if is directly contained by some resource. There are also org.eclipse.emf.ecore.util.EcoreUtil.remove(Setting, Object) and org.eclipse.emf.ecore.util.EcoreUtil.remove(EObject, EStructuralFeature, Object), not to mention org.eclipse.emf.ecore.util.EcoreUtil.delete(EObject) which will also remove all references to the object being deleted.

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Re: Remove item from list using its containment Setting [message #1795764 is a reply to message #1795726]

Fri, 28 September 2018 07:47

Erdal Karaca

Messages: 853
Registered: July 2009

Senior Member

Thanks, Ed!
That is what I was looking for!

Ed Merks wrote on Thu, 27 September 2018 12:35

You can use org.eclipse.emf.ecore.util.EcoreUtil.remove(EObject) to remove an object from its container; this will remove it from its resource if is directly contained by some resource. There are also org.eclipse.emf.ecore.util.EcoreUtil.remove(Setting, Object) and org.eclipse.emf.ecore.util.EcoreUtil.remove(EObject, EStructuralFeature, Object), not to mention org.eclipse.emf.ecore.util.EcoreUtil.delete(EObject) which will also remove all references to the object being deleted.

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