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[EMF Compare] Retrieve original value of AttributeChange [message #1049734]

Fri, 26 April 2013 07:53

Aleksandar Toshovski

Messages: 78
Registered: December 2011

Member

How can I retrieve the old value of AttributeChange? With

 diff.getValue()

I can retrieve the new value of the Attribute, but I don't find a way to retrieve the old one.

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Re: [EMF Compare] Retrieve original value of AttributeChange [message #1049931 is a reply to message #1049734]

Fri, 26 April 2013 13:17

Laurent Goubet

Messages: 1895
Registered: July 2009

Senior Member

Aleksandar,

You need to look the "old" value up yourself. Note that the following is only true for differences of type "CHANGE" (single-valued attribute). For diffs of type "ADD" or "DELETE" (multi-valued attribute), there is no old value.

In two-way :

Object oldAttributeValue = null;
Match match = diff.getMatch();
if (match.getRight() != null) {
  value = match.getRight().eGet(diff.getAttribute());
} else {
  // this item didn't exist previously
}

In three-way:

Match match = diff.getMatch();
if (match.getOrigin() != null) {
  value = match.getOrigin().eGet(diff.getAttribute());
} else {
  // this item didn't exist previously
}

as you can see, there is no real sense to "old" value : it could have been null, or the object where we detected a change didn't previously exist.

Laurent Goubet
Obeo

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