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https://issues.apache.org/jira/browse/OAK-6378?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16059420#comment-16059420
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Francesco Mari commented on OAK-6378:
-------------------------------------

bq. The note in the SegmentWriter.writeNode() Javadoc actually tells this story.

I will review and fix the documentation when this change lands in trunk. While 
I agree with you on the aesthetics of the change (or the lack thereof), I 
believe that {{SegmentWriter}} should provide the mechanism for writing a node, 
and not dictate the policy of how the node is used after it's written. The 
policy is better dictated by the record classes, that together provide a 
consistent read/write view on the data according to the initially provided 
{{SegmentReader}}, {{SegmentWriter}} and {{BlobStore}}.

> Move the SegmentWriter API to its own interface
> -----------------------------------------------
>
>                 Key: OAK-6378
>                 URL: https://issues.apache.org/jira/browse/OAK-6378
>             Project: Jackrabbit Oak
>          Issue Type: Bug
>          Components: segment-tar
>            Reporter: Francesco Mari
>            Assignee: Francesco Mari
>             Fix For: 1.8, 1.7.3
>
>
> In order to isolate {{SegmentWriter}} from the rest of the implementation, 
> and to match the corresponding {{SegmentReader}}, I extracted the API exposed 
> by {{SegmentWriter}} to its own interface and moved its implementation in a 
> separate class.
> Moreover, I cleaned up the {{SegmentWriter}} a bit by letting. every method 
> of its interface always return a {{RecordId}}. Before the refactoring, some 
> methods returned concrete implementations of record classes. The cleanup 
> improves the uniformity of the {{SegmentWriter}} interface.
> I see potential in this change for the following reasons.
> * The concrete record implementations ({{SegmentNodeState}}, {{Template}}, 
> {{MapRecord}}, etc.) might be implemented directly on top of the 
> {{SegmentReader}} and {{SegmentWriter}} API, moved to a different package and 
> tested separately from the rest of the code.
> * {{SegmentWrier}} and {{SegmentReader}} provide a higher level API that 
> isolates the {{SegmentStore}} and its supporting classes. Code using only 
> {{SegmentWriter}} and {{SegmentReader}} might be able to use {{RecordId}} 
> instances as opaque handles to the underlying records, with beneficial 
> effects on code decoupling.
> I have a working version of the refactoring in [this branch on 
> GitHub|https://github.com/francescomari/jackrabbit-oak/tree/segment-writer].



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