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EMFCompare graph structure and change information [message #1006592] Thu, 31 January 2013 23:54 Go to next message
Asha Mising name is currently offline Asha Mising name
Messages: 18
Registered: July 2009
Junior Member
Hi,

Can I know more about EMFCompare.

1) I observed that while showing graph structure in EMFCompare it shows tree w.r.t composition of association. Hence change in attribute type is not shown as diff when
typename is changed. Is my understanding correct ?

2) Can I configure the graph it shows in EMFCompare dynamically?

3) Does EMFCompare uses change information in some form for finding
differences?

Regards,
Asha.
Re: EMFCompare graph structure and change information [message #1006638 is a reply to message #1006592] Fri, 01 February 2013 04:56 Go to previous messageGo to next message
Laurent Goubet is currently offline Laurent Goubet
Messages: 1621
Registered: July 2009
Senior Member
Asha,

I'll assume you are using EMF Compare 2, these answers reflect that :

1) and 2) All differences are displayed; changing the attribute type is just another difference. Refernece and attribute changes are displayed in the form of a list (with all values from either left and right displayed). An exception to this rule are changes to textual attributes that are displayed in text editors. Mikael should be able to tell you more about this and the changes that are currently being implemented on that side.

3) What do you mean by that? What are "change information"? When comparing resources, EMF Compare makes a first pass to determine whether the two (or three) given files are binary identical before any more complex computation. You might want to take a look at the overview of the comparison process and what we consider to be a logical model for more on this.

Please refine your questions if this does not answer.

Laurent Goubet
Obeo

[Updated on: Fri, 01 February 2013 05:00]

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Re: EMFCompare graph structure and change information [message #1006646 is a reply to message #1006638] Fri, 01 February 2013 05:19 Go to previous message
Mikael Barbero is currently offline Mikael Barbero
Messages: 53
Registered: July 2009
Member
Asha,

As a complement to 1), EMF Compare 2 displays the computed differences following this rationale:

- References changes are displayed by comparing the lists of referenced elements with move, addition and deletion depicted with boxes and placeholders linked between the lists
- Attribute changes of single valued EAttribute (upper bounds == 1) with an instance class equals to java.lang.String are displayed using classical text viewer (the one that is used when compared text files)
- Attribute changes (other than the specific case above), are displayed by comparing the lists of values with move, addition, deletion and set/unset depicted with boxes and placeholders between the lists
- Resource attachment changes are displayed in the same way as reference changes except that their is not EReference to get, but the contents of matched resources.

BTW, there is ongoing work to display containment reference changes in a tree instead as in a list to be able to display move between references and to let the user see all the containment reference changes at once.

2) It is possible to change the way EMF Compare displays the graph, but it is not possible dynamically. There is some classes to be extended and extension points to be filled. Unfortunately, there is currently no documentation how to do that. If you really want to do that, I can provide you some entry points.

3) If by "change information" you mean the change model that you can record with an EMF ChangeRecorder, the answer is no. EMF Compare uses some engines to match and compute differences between models after editing/changes.... The results is a "Comparison model". I don't think it is impossible to bridge EMF ChangeModel and EMF Compare comparison model in one direction and/or another but we do not take many experiments in that way. If you are interested in contributing such a thing, we would very keen to help you do so.


Best regards,

Mikael Barbero
Obeo
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