mirror of https://github.com/apache/lucene.git
627 lines
30 KiB
HTML
627 lines
30 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<!-- Content Stylesheet for Site -->
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<!-- start the processing -->
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<!-- ====================================================================== -->
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<!-- Main Page Section -->
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<!-- ====================================================================== -->
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"/>
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<title>Jakarta Lucene - Plan for enhancements to Lucene</title>
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</head>
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<body bgcolor="#ffffff" text="#000000" link="#525D76">
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<table border="0" width="100%" cellspacing="0">
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<!-- TOP IMAGE -->
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<tr>
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<td align="left">
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<a href="http://jakarta.apache.org"><img src="http://jakarta.apache.org/images/jakarta-logo.gif" border="0"/></a>
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</td>
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<td align="right">
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<a href="http://jakarta.apache.org/lucene/"><img src="./images/lucene_green_300.gif" alt="Jakarta Lucene" border="0"/></a>
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</td>
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</tr>
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</table>
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<table border="0" width="100%" cellspacing="4">
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<tr><td colspan="2">
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<hr noshade="" size="1"/>
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</td></tr>
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<tr>
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<!-- LEFT SIDE NAVIGATION -->
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<td width="20%" valign="top" nowrap="true">
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<p><strong>About</strong></p>
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<ul>
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<li> <a href="./index.html">Overview</a>
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</li>
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<li> <a href="./powered.html">Powered by Lucene</a>
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</li>
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<li> <a href="./whoweare.html">Who We Are</a>
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</li>
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<li> <a href="http://jakarta.apache.org/site/mail.html">Mailing Lists</a>
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</li>
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</ul>
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<p><strong>Resources</strong></p>
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<ul>
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<li> <a href="http://lucene.sourceforge.net/cgi-bin/faq/faqmanager.cgi">FAQ (Official)</a>
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</li>
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<li> <a href="./gettingstarted.html">Getting Started</a>
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</li>
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<li> <a href="http://www.jguru.com/faq/Lucene">JGuru FAQ</a>
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</li>
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<li> <a href="http://jakarta.apache.org/site/bugs.html">Bugs</a>
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</li>
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<li> <a href="http://nagoya.apache.org/bugzilla/buglist.cgi?bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&email1=&emailtype1=substring&emailassigned_to1=1&email2=&emailtype2=substring&emailreporter2=1&bugidtype=include&bug_id=&changedin=&votes=&chfieldfrom=&chfieldto=Now&chfieldvalue=&product=Lucene&short_desc=&short_desc_type=allwordssubstr&long_desc=&long_desc_type=allwordssubstr&bug_file_loc=&bug_file_loc_type=allwordssubstr&keywords=&keywords_type=anywords&field0-0-0=noop&type0-0-0=noop&value0-0-0=&cmdtype=doit&order=%27Importance%27">Lucene Bugs</a>
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</li>
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<li> <a href="./resources.html">Articles</a>
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</li>
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<li> <a href="./api/index.html">Javadoc</a>
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</li>
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<li> <a href="./contributions.html">Contributions</a>
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</li>
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</ul>
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<p><strong>Plans</strong></p>
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<ul>
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<li> <a href="./luceneplan.html">Application Extensions</a>
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</li>
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</ul>
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<p><strong>Download</strong></p>
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<ul>
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<li> <a href="http://jakarta.apache.org/site/binindex.html">Binaries</a>
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</li>
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<li> <a href="http://jakarta.apache.org/site/sourceindex.html">Source Code</a>
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</li>
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<li> <a href="http://jakarta.apache.org/site/cvsindex.html">CVS Repositories</a>
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</li>
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</ul>
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<p><strong>Jakarta</strong></p>
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<ul>
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<li> <a href="http://jakarta.apache.org/site/getinvolved.html">Get Involved</a>
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</li>
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<li> <a href="http://jakarta.apache.org/site/acknowledgements.html">Acknowledgements</a>
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</li>
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<li> <a href="http://jakarta.apache.org/site/contact.html">Contact</a>
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</li>
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<li> <a href="http://jakarta.apache.org/site/legal.html">Legal</a>
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</li>
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</ul>
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</td>
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<td width="80%" align="left" valign="top">
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<table border="0" cellspacing="0" cellpadding="2" width="100%">
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<tr><td bgcolor="#525D76">
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<font color="#ffffff" face="arial,helvetica,sanserif">
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<a name="Purpose"><strong>Purpose</strong></a>
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</font>
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</td></tr>
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<tr><td>
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<blockquote>
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<p>
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The purpose of this document is to outline plans for
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making <a href="http://jakarta.apache.org/lucene">
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Jakarta Lucene</a> work as a more general drop-in
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component. It makes the assumption that this is an
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objective for the Lucene user and development community.
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</p>
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<p>
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The best reference is <a href="http://www.htdig.org">
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htDig</a>, though it is not quite as sophisticated as
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Lucene, it has a number of features that make it
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desireable. It however is a traditional c-compiled app
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which makes it somewhat unpleasent to install on some
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platforms (like Solaris!).
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</p>
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<p>
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This plan is being submitted to the Lucene developer
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community for an initial reaction, advice, feedback and
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consent. Following this it will be submitted to the
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Lucene user community for support. Although, I'm (Andy
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Oliver) capable of providing these enhancements by
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myself, I'd of course prefer to work on them in concert
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with others.
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</p>
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<p>
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While I'm outlaying a fairly large featureset, these can
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be implemented incrementally of course (and are probably
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best if done that way).
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</p>
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</blockquote>
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</p>
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</td></tr>
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<tr><td><br/></td></tr>
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</table>
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<table border="0" cellspacing="0" cellpadding="2" width="100%">
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<tr><td bgcolor="#525D76">
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<font color="#ffffff" face="arial,helvetica,sanserif">
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<a name="Goal and Objectives"><strong>Goal and Objectives</strong></a>
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</font>
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</td></tr>
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<tr><td>
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<blockquote>
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<p>
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The goal is to provide features to Lucene that allow it
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to be used as a dropin search engine. It should provide
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many of the features of projects like <a href="http://www.htdig.org">htDig</a> while surpassing
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them with unique Lucene features and capabillities such as
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easy installation on and java-supporting platform,
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and support for document fields and field searches. And
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of course, <a href="http://apache.org/LICENSE">
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a pragmatic software license</a>.
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</p>
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<p>
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To reach this goal we'll implement code to support the
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following objectives that augment but do not replace
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the current Lucene featureset.
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</p>
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<ul>
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<li>
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Document Location Independance - meaning mapping
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real contexts to runtime contexts.
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Essentially, if the document is at
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/var/www/htdocs/mydoc.html, I probably want it
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indexed as
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http://www.bigevilmegacorp.com/mydoc.html.
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</li>
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<li>
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Standard methods of creating central indicies -
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file system indexing is probably less useful in
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many environments than is *remote* indexing (for
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instance http). I would suggest that most folks
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would prefer that general functionality be
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suppored by Lucene instead of having to write
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code for every indexing project. Obviously, if
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what they are doing is *special* they'll have to
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code, but general document indexing accross
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webservers would not qualify.
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</li>
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<li>
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Document interperatation abstraction - currently
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one must handle document object construction via
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custom code. A standard interface for plugging
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in format handlers should be supported.
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</li>
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<li>
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Mime and file-extension to document
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interperatation mapping.
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</li>
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</ul>
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</blockquote>
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</p>
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</td></tr>
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<tr><td><br/></td></tr>
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</table>
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<table border="0" cellspacing="0" cellpadding="2" width="100%">
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<tr><td bgcolor="#525D76">
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<font color="#ffffff" face="arial,helvetica,sanserif">
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<a name="Crawlers"><strong>Crawlers</strong></a>
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</font>
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</td></tr>
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<tr><td>
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<blockquote>
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<p>
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Crawlers are data source executable code. They crawl a file
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system, ftp site, web site, etc. to create the index.
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These standard crawlers may not make ALL of Lucene's
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functionality available, though they should be able to
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make most of it available through configuration.
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</p>
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<p>
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<b> Abstract Crawler </b>
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</p>
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<p>
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The AbstractCrawler is basically the parent for all
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Crawler classes. It provides implementation for the
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following functions/properties:
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</p>
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<ul>
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<li>
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index path - where to write the index.
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</li>
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<li>
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cui - create or update the index
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</li>
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<li>
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root context - the start of the pathname
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that should be replaced by the
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replace with property or dropped
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entirely. Example: /opt/tomcat/webapps
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</li>
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<li>
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replace with - when specified replaces
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the root context. Example:
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http://jakarta.apache.org.
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</li>
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<li>
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replacement type - the type of
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replacewith path: relative, url or
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path.
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</li>
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<li>
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location - the location to start
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indexing at.
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</li>
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<li>
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doctypes - only index documents with
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these doctypes. If not specified all
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registered mime-types are used.
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Example: "xml,doc,html"
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</li>
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<li>
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recursive - if not specified is turned
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off.
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</li>
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<li>
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level - optional level of directory or
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links to traverse. By default is
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assumed to be infinite. Recursive must
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be turned on or this is ignored. Range:
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0 - Long.MAX_VALUE.
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</li>
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<li>
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SleeptimeBetweenCalls - can be used to
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avoid flooding a machine with too many
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requests
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</li>
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<li>
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RequestTimeout - kill the crawler
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request after the specified period of
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inactivity.
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</li>
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<li>
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IncludeFilter - include only items
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matching filter. (can occur mulitple
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times)
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</li>
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<li>
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ExcludeFilter - exclude only items
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matching filter. (can occur multiple
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times)
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</li>
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<li>
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ExpandOnly - use but do not index items
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that match this pattern (regex?) (can
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occur multiple times)
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</li>
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<li>
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NoExpand - Index but do not follow the
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links in items that match this pattern
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(regex?) (can occur multiple times)
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</li>
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<li>
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MaxItems - stops indexing after x
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documents have been indexed.
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</li>
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<li>
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MaxMegs - stops indexing after x megs
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have been indexed.. (should this be in
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specific crawlers?)
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</li>
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<li>
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properties - in addition to the settings
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(probably from the command line) read
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this properties file and get them from
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it. Command line options override
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the properties file in the case of
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duplicates. There should also be an
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enivironment variable or VM parameter to
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set this.
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</li>
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</ul>
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<p>
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<b>FileSystemCrawler</b>
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</p>
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<p>
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This should extend the AbstractCrawler and
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support any addtional options required for a
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filesystem index.
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</p>
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<p>
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<b>HTTP Crawler </b>
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</p>
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<p>
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Supports the AbstractCrawler options as well as:
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</p>
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<ul>
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<li>
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span hosts - Wheter to span hosts or not,
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by default this should be no.
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</li>
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<li>
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restrict domains - (ignored if span
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hosts is not enabled). Whether all
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spanned hosts must be in the same domain
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(default is off).
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</li>
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<li>
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try directories - Whether to attempt
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directory listings or not (so if you
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recurse and go to
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/nextcontext/index.html this option says
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to also try /nextcontext to get the dir
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lsiting)
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</li>
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<li>
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map extensions -
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(always/default/never/fallback). Wether
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to always use extension mapping, by
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default (fallback to mime type), NEVER
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or fallback if mime is not available
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(default).
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</li>
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<li>
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ignore robots - ignore robots.txt, on or
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off (default - off)
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</li>
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</ul>
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</blockquote>
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</p>
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</td></tr>
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<tr><td><br/></td></tr>
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</table>
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<table border="0" cellspacing="0" cellpadding="2" width="100%">
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<tr><td bgcolor="#525D76">
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<font color="#ffffff" face="arial,helvetica,sanserif">
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<a name="MIMEMap"><strong>MIMEMap</strong></a>
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</font>
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</td></tr>
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<tr><td>
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<blockquote>
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<p>
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A configurable registry of document types, their
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description, an identifyer, mime-type and file
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extension. This should map both MIME -> factory
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and extension -> factory.
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</p>
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<p>
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This might be configured at compile time or by a
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properties file, etc. For example:
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</p>
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<table>
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<tr>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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Description
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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Identifier
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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Extensions
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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MimeType
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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DocumentFactory
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</font>
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</td>
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</tr>
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<tr>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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"Word Document"
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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"doc"
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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"doc"
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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"vnd.application/ms-word"
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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POIWordDocumentFactory
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</font>
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</td>
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</tr>
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<tr>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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"HTML Document"
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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"html"
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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"html,htm"
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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</font>
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</td>
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<td bgcolor="#a0ddf0" colspan="" rowspan="" valign="top" align="left">
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<font color="#000000" size="-1" face="arial,helvetica,sanserif">
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HTMLDocumentFactory
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</font>
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</td>
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</tr>
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</table>
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</blockquote>
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</p>
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</td></tr>
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<tr><td><br/></td></tr>
|
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</table>
|
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<table border="0" cellspacing="0" cellpadding="2" width="100%">
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<tr><td bgcolor="#525D76">
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<font color="#ffffff" face="arial,helvetica,sanserif">
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<a name="DocumentFactory"><strong>DocumentFactory</strong></a>
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</font>
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</td></tr>
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<tr><td>
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<blockquote>
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<p>
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An interface for classes which create document objects
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for particular file types. Examples:
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HTMLDocumentFactory, DOCDocumentFactory,
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XLSDocumentFactory, XML DocumentFactory.
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</p>
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</blockquote>
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</p>
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</td></tr>
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<tr><td><br/></td></tr>
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</table>
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<table border="0" cellspacing="0" cellpadding="2" width="100%">
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<tr><td bgcolor="#525D76">
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<font color="#ffffff" face="arial,helvetica,sanserif">
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<a name="FieldMapping classes"><strong>FieldMapping classes</strong></a>
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</font>
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</td></tr>
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<tr><td>
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<blockquote>
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<p>
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A class taht maps standard fields from the
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DocumentFactories into *fields* in the Document objects
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they create. I suggest that a regular expression system
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or xpath might be the most universal way to do this.
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For instance if perhaps I had an XML factory that
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represented XML elements as fields, I could map content
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from particular fields to ther fields or supress them
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entirely. We could even make this configurable.
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</p>
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<p>
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for example:
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</p>
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<ul>
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<li>
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htmldoc.properties
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</li>
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<li>
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suppress=*
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</li>
|
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<li>
|
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author=content:g/author\:\ ........................................./
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</li>
|
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<li>
|
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author.suppress=false
|
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</li>
|
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<li>
|
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title=content:g/title\:\ ........................................./
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</li>
|
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<li>
|
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title.suppress=false
|
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</li>
|
|
</ul>
|
|
<p>
|
|
In this example we map html documents such that all
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|
fields are suppressed but author and title. We map
|
|
author and title to anything in the content matching
|
|
author: (and x characters). Okay my regular expresions
|
|
suck but hopefully you get the idea.
|
|
</p>
|
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</blockquote>
|
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</p>
|
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</td></tr>
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<tr><td><br/></td></tr>
|
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</table>
|
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<table border="0" cellspacing="0" cellpadding="2" width="100%">
|
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<tr><td bgcolor="#525D76">
|
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<font color="#ffffff" face="arial,helvetica,sanserif">
|
|
<a name="Final Thoughts"><strong>Final Thoughts</strong></a>
|
|
</font>
|
|
</td></tr>
|
|
<tr><td>
|
|
<blockquote>
|
|
<p>
|
|
We might also consider eliminating the DocumentFactory
|
|
entirely by making an AbstractDocument from which the
|
|
current document object would inherit from. I
|
|
experimented with this locally, and it was a relatively
|
|
minor code change and there was of course no difference
|
|
in performance. The Document Factory classes would
|
|
instead be instances of various subclasses of
|
|
AbstractDocument.
|
|
</p>
|
|
<p>
|
|
My inspiration for this is HTDig (http://www.htdig.org/).
|
|
While this goes slightly beyond what HTDig provides by
|
|
providing field mapping (where HTDIG is just interested
|
|
in Strings/numbers wherever they are found), it provides
|
|
at least what I would need to use this as a dropin for
|
|
most places I contract at (with the obvious exception of
|
|
a default set of content handlers which would of course
|
|
develop naturally over time).
|
|
</p>
|
|
<p>
|
|
I am able to certainly contribute to this effort if the
|
|
development community is open to it. I'd suggest we do
|
|
it iteratively in stages and not aim for all of this at
|
|
once (for instance leave out the field mapping at first).
|
|
</p>
|
|
<p>
|
|
|
|
Anyhow, please give me some feedback, counter
|
|
suggestions, let me know if I'm way off base or out of
|
|
line, etc. -Andy
|
|
</p>
|
|
</blockquote>
|
|
</p>
|
|
</td></tr>
|
|
<tr><td><br/></td></tr>
|
|
</table>
|
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</td>
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</tr>
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|
<!-- FOOTER -->
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<tr><td colspan="2">
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<hr noshade="" size="1"/>
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</td></tr>
|
|
<tr><td colspan="2">
|
|
<div align="center"><font color="#525D76" size="-1"><em>
|
|
Copyright © 1999-2002, Apache Software Foundation
|
|
</em></font></div>
|
|
</td></tr>
|
|
</table>
|
|
</body>
|
|
</html>
|
|
<!-- end the processing -->
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