[tigerstripe-dev] Annotations Conversation

["John Worrell (jworrell)" <jworrell@xxxxxxxxx>]

Hi Yuri,

 

Many thanks for your help earlier this morning in pointing out that I need to keep the Annotation object I create in order that any changes I make to the content can be saved back - that is, it is not correct for me to hold the content alone and to look later in the AnnotationManager for the Annotation object that wraps the content.

 

So, I tried holding the Annotation object and saving that, but this gives me a NullPointerException in  AnnotationStorage.save(Annotation a) because there is no matching ChangeRecorder in the changes Map. I have debuggedthis and I find that the reason for this lies in the way in which the id is assigned to an Annotation instance... That is, in AnnotationStorage.add(Annotation a) we have the code:

 

addToList(annotation, annotation.getUri()); // add to list for URI

trackChanges(annotation);                        // create ChangeRecorder and put in changes Map - id is null at this point

database.write(annotation);                       // assign an id to the Annotation and write to DB

fireAnnotationAdded(annotation);

 

the crucial point is that if the id is null the hash-code is computed using an algorithm in EObject and not from the id, but when I go back and pass my Annotation into the save(...) method ithas an id and so a different hash-code is computed... which means I can never match my Annotation to ind the ChangeRcorder.

 

So, what I have done as a temporary measure is to swap the order of the trachChanges(...)database.write(...) and this seems to work. However, I think the correct thing to do is to assign an id to the Annotation at the point of creation, and ideally to make that id immutable/read-only.

 

What do you think? Have I mis-interpreted?

 

Thanks again,

 

JohnW

 

John Worrell Technical Leader jworrell@xxxxxxxxx Phone: +44 208824 9410 Mobile: +44 7789 922290	Cisco Systems Limited 250 Longwater Avenue Reading RG2 6GB United Kingdom Cisco home page

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