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<div class="navpath"><a class="el" href="namespaceXapian.html">Xapian</a>::<a class="el" href="classXapian_1_1MultiValueKeyMaker.html">MultiValueKeyMaker</a>
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<h1>Xapian::MultiValueKeyMaker Class Reference</h1><!-- doxytag: class="Xapian::MultiValueKeyMaker" --><!-- doxytag: inherits="Xapian::KeyMaker" --><a class="el" href="classXapian_1_1KeyMaker.html" title="Virtual base class for key making functors.">KeyMaker</a> subclass which combines several values.
<a href="#_details">More...</a>
<p>
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Inheritance diagram for Xapian::MultiValueKeyMaker:</div>
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<p><center><img src="classXapian_1_1MultiValueKeyMaker__inherit__graph.png" border="0" usemap="#Xapian_1_1MultiValueKeyMaker__inherit__map" alt="Inheritance graph"></center>
<map name="Xapian_1_1MultiValueKeyMaker__inherit__map">
<area shape="rect" href="classXapian_1_1KeyMaker.html" title="Virtual base class for key making functors." alt="" coords="37,7,171,33"></map>
<center><font size="2">[<a href="graph_legend.html">legend</a>]</font></center></div>
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<a href="classXapian_1_1MultiValueKeyMaker-members.html">List of all members.</a><table border="0" cellpadding="0" cellspacing="0">
<tr><td></td></tr>
<tr><td colspan="2"><br><h2>Public Member Functions</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">virtual std::string </td><td class="memItemRight" valign="bottom"><a class="el" href="classXapian_1_1MultiValueKeyMaker.html#8f827517ed1ea394f99d4db362f23b31">operator()</a> (const <a class="el" href="classXapian_1_1Document.html">Xapian::Document</a> &doc) const </td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Build a key string for a <a class="el" href="classXapian_1_1Document.html" title="A handle representing a document in a Xapian database.">Document</a>. <a href="#8f827517ed1ea394f99d4db362f23b31"></a><br></td></tr>
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<hr><a name="_details"></a><h2>Detailed Description</h2>
<a class="el" href="classXapian_1_1KeyMaker.html" title="Virtual base class for key making functors.">KeyMaker</a> subclass which combines several values.
<p>
When the result is used for sorting, results are ordered by the first value. In the event of a tie, the second is used. If this is the same for both, the third is used, and so on. If <em>reverse</em> is true for a value, then the sort order for that value is reversed.<p>
When used for collapsing, the documents will only be considered equal if all the values specified match. If none of the specified values are set then the generated key will be empty, so such documents won't be collapsed (which is consistent with the behaviour in the "collapse on a value" case). If you'd prefer that documents with none of the keys set are collapsed together, then you can set <em>reverse</em> for at least one of the values. Other than this, it isn't useful to set <em>reverse</em> for collapsing. <hr><h2>Member Function Documentation</h2>
<a class="anchor" name="8f827517ed1ea394f99d4db362f23b31"></a><!-- doxytag: member="Xapian::MultiValueKeyMaker::operator()" ref="8f827517ed1ea394f99d4db362f23b31" args="(const Xapian::Document &doc) const " -->
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<td class="memname">virtual std::string Xapian::MultiValueKeyMaker::operator() </td>
<td>(</td>
<td class="paramtype">const <a class="el" href="classXapian_1_1Document.html">Xapian::Document</a> & </td>
<td class="paramname"> <em>doc</em> </td>
<td> ) </td>
<td> const<code> [virtual]</code></td>
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<p>
Build a key string for a <a class="el" href="classXapian_1_1Document.html" title="A handle representing a document in a Xapian database.">Document</a>.
<p>
These keys can be used for sorting or collapsing matching documents.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>doc</em> </td><td><a class="el" href="classXapian_1_1Document.html" title="A handle representing a document in a Xapian database.">Document</a> object to build a key for. </td></tr>
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<p>Implements <a class="el" href="classXapian_1_1KeyMaker.html#cd0a775f8546a830833357e5d792bedc">Xapian::KeyMaker</a>.</p>
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<hr>The documentation for this class was generated from the following file:<ul>
<li>xapian/<a class="el" href="keymaker_8h.html">keymaker.h</a></ul>
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Documentation for Xapian (version 1.2.12).<br>
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