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https://issues.apache.org/jira/browse/NUTCH-2381?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16939336#comment-16939336
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Sebastian Nagel commented on NUTCH-2381:
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Good point: "A particular iteration order is not specified for {{HashMap}}
objects - any code that depends on iteration order should be fixed."
([https://docs.oracle.com/javase/8/docs/technotes/guides/collections/changes8.html)]
Will provide fix.
CAVEAT: while it makes the TextProfileSignature more reliable, it will change
the signatures in an already existing CrawlDb.
> In some situations the class TextProfileSignature gives different signatures
> for the same text "profile" page.
> --------------------------------------------------------------------------------------------------------------
>
> Key: NUTCH-2381
> URL: https://issues.apache.org/jira/browse/NUTCH-2381
> Project: Nutch
> Issue Type: Bug
> Components: crawldb
> Affects Versions: 1.13
> Reporter: Rodrigo Joni Sestari
> Priority: Major
> Labels: signature
> Fix For: 1.16
>
>
> In some situations the class TextProfileSignature gives different signatures
> for the same text "profile" page.
> The method TextProfileSignature.calculate uses a HashMap to salve the tokens,
> after some process, the tokens come sorted by decreasing frequency.
> For some pages like "http://curia.europa.eu/jcms/"; the text "profile" is the
> same but the signature come different for each fetch.
> Its happens because the tokens are sorted only by decreasing frequency.
> Tokens with the same frequency maybe not have the same order in different
> fetchs.
> The HashMap no guarantees as to the order of the map and not guarantee that
> the order will remain constant over time.
> My suggestion is change the methods TokenComparator.compare in order to sort
> by frequency and Name.
> Rodrigo
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