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From "Andrzej Bialecki (JIRA)" <j...@apache.org>
Subject [jira] Commented: (NUTCH-443) allow parsers to return multiple Parse object, this will speed up the rss parser
Date Wed, 14 Feb 2007 15:15:06 GMT

    [ https://issues.apache.org/jira/browse/NUTCH-443?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12473114
] 

Andrzej Bialecki  commented on NUTCH-443:
-----------------------------------------

The contract for ParseUtil.getFirstParseEntry() seems unclear - since in most cases this is
a HashMap, there is no predictable way to get the first entry added to the map ... I propose
also that we should use a specialized class instead of general-purpose Map; and then we can
record in that class which entry was the first. Also, the naming of some methods seems a bit
awkward - why should we insist that we createSingleEntryMap while we create an ordinary Map,
and we don't use this special-case knowledge later? I suggest to simply name it createParseMap.

In recent versions of Hadoop there is a GenericWritable class - it replaces ObjectWritable
when classes are known in advance, and provides a more compact representation.

Changes to MapWritable must preserve old code values, at most adding some new ones - otherwise
the new code will get confused when working with older data.

CrawlDbReducer, TODO item: this should be the time stored under Nutch.FETCH_TIME_KEY, no?

If I'm not mistaken, ParseUtil doesn't need the import of HashMap, only Map.

The new model for returning results from parse plugins allows a much better approach to parsing
archives (eg. zip files) containing multiple documents in supported formats - although this
should be a separate patch.

> allow parsers to return multiple Parse object, this will speed up the rss parser
> --------------------------------------------------------------------------------
>
>                 Key: NUTCH-443
>                 URL: https://issues.apache.org/jira/browse/NUTCH-443
>             Project: Nutch
>          Issue Type: New Feature
>          Components: fetcher
>    Affects Versions: 0.9.0
>            Reporter: Renaud Richardet
>         Assigned To: Chris A. Mattmann
>            Priority: Minor
>             Fix For: 0.9.0
>
>         Attachments: NUTCH-443-draft-v1.patch, NUTCH-443-draft-v2.patch, NUTCH-443-draft-v3.patch,
NUTCH-443-draft-v4.patch, NUTCH-443-draft-v5.patch, NUTCH-443-draft-v6.patch, parse-map-core-draft-v1.patch,
parse-map-core-untested.patch, parsers.diff
>
>
> allow Parser#parse to return a Map<String,Parse>. This way, the RSS parser can
return multiple parse objects, that will all be indexed separately. Advantage: no need to
fetch all feed-items separately.
> see the discussion at http://www.nabble.com/RSS-fecter-and-index-individul-how-can-i-realize-this-function-tf3146271.html

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