How are 'ea_localid' values distributed in Enterprise Architect API?

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While working with the Enterprise Architect API I have noticed that when you export an EA project to XMI, several different kinds of elements get an attribute called ea_localid. That means in the XMI you'll find a tag that has the ea_localid as an attribute. This attribute seems to be used to reference source and target of connecting elements (at least this is valid for 'transitions', as we are working with State Machine diagrams).

So far, so good. Now the problem for my intended usage is that these values seem to be newly distributed every time you do an import and an export. EDIT: it is not quite clear to me when exactly during this process. EDIT #2 It seems to happen on import.

That means after having exported your project, reimporting it, changing nothing and then exporting it again gives the generated XMI document a set of different ea_localid values. Moreover, it seems that some values that used to belong to one element can now be used for an entirely different one.

Does anybody know anything about the distribution mechanism? Or, even better, a way of emulating it? Or a way to reset all counters?

As far as I've seen, generally there seem to be different classes of elements and within these classes a new ea_localid for the next element is generated by counting +1. So the first one has the value 1, then the next one 2 and so on.

My goal here is doing 'roundtrips' (XMI --> project --> XMI ...) and always getting the same ea_localid values, possibly by editing the XMI document after export. Any help or suggestions would be highly appreciated. Cheers

enterprise-architect xml python
2 Answers

The ea_localid represents the elementID of elements (or AttributeID for attributes etc...)

In EA each "thing" has two ID's. A numeric ID, and a GUID.

The numeric ID (e.g. t_object.Object_ID) is used as key in most relations, but this is not stable.

Things like importing XMI files can reset the numeric ID's. This explains why the ea_localID changes.

If you are looking for a stable ID you should use the GUID. This one is guaranteed to stay the same, even after exporting and importing to other models. (as long as you don't set the flag Strip GUIDs when importing)

In the xmi file you'll find those stable id's in the attribte xmi.id e.g

<UML:Class name="Aannemer" xmi.id="EAID_04A526DF_7F07_4475_8E65_16D2D88CEECD" visibility="public" namespace="EAPK_0345C8A9_9E8F_42c5_9931_CB842233B11B" isRoot="false" isLeaf="false" isAbstract="false" isActive="false">

This value corresponds to the ea_guid columns in each of the tables.

user_20181330

So, after some testing I have found out that regarding the aforementioned goal of doing a roundtrip (xmi --> import to EA --> xmi) and always getting the exact same document, the easiest solution is ...

running a filter over the xmi that just deletes all nodes containing ea_localid, ea_sourceID (sic!) and ea_targetID values.

On reimport EA will just assign them new values. The information regarding source and target of 'transitions' and other connecting elements is also stored with the GUID, so there is no loss of information.

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