﻿<html xmlns:MSHelp="http://msdn.microsoft.com/mshelp" xmlns:mshelp="http://msdn.microsoft.com/mshelp" xmlns:ddue="http://ddue.schemas.microsoft.com/authoring/2003/5" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:msxsl="urn:schemas-microsoft-com:xslt"><head><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8" /><META NAME="save" CONTENT="history" /><title>FieldMaskingSpanQuery Class</title><meta name="Language" content="en-us" /><meta name="System.Keywords" content="FieldMaskingSpanQuery class" /><meta name="System.Keywords" content="Lucene.Net.Search.Spans.FieldMaskingSpanQuery class" /><meta name="System.Keywords" content="FieldMaskingSpanQuery class, about FieldMaskingSpanQuery class" /><meta name="Microsoft.Help.F1" content="Lucene.Net.Search.Spans.FieldMaskingSpanQuery" /><meta name="Microsoft.Help.Id" content="T:Lucene.Net.Search.Spans.FieldMaskingSpanQuery" /><meta name="Description" content="Wrapper to allow {@link SpanQuery} objects participate in composite single-field SpanQueries by 'lying' about their search field." /><meta name="Microsoft.Help.ContentType" content="Reference" /><link rel="stylesheet" type="text/css" href="../styles/Presentation.css" /><link rel="stylesheet" type="text/css" href="ms-help://Hx/HxRuntime/HxLink.css" /><script type="text/javascript" src="../scripts/EventUtilities.js"> </script><script type="text/javascript" src="../scripts/SplitScreen.js"> </script><script type="text/javascript" src="../scripts/Dropdown.js"> </script><script type="text/javascript" src="../scripts/script_manifold.js"> </script><script type="text/javascript" src="../scripts/script_feedBack.js"> </script><script type="text/javascript" src="../scripts/CheckboxMenu.js"> </script><script type="text/javascript" src="../scripts/CommonUtilities.js"> </script><meta name="container" content="Lucene.Net.Search.Spans" /><meta name="file" content="77f74195-ffe6-088f-64e4-2b27eb91a801" /><meta name="guid" content="77f74195-ffe6-088f-64e4-2b27eb91a801" /><xml><MSHelp:Attr Name="AssetID" Value="T:Lucene.Net.Search.Spans.FieldMaskingSpanQuery" /><MSHelp:TOCTitle Title="FieldMaskingSpanQuery Class" /><MSHelp:RLTitle Title="FieldMaskingSpanQuery Class (Lucene.Net.Search.Spans)" /><MSHelp:Keyword Index="A" Term="T:Lucene.Net.Search.Spans.FieldMaskingSpanQuery" /><MSHelp:Keyword Index="A" Term="frlrfLuceneNetSearchSpansFieldMaskingSpanQueryClassTopic" /><MSHelp:Keyword Index="K" Term="FieldMaskingSpanQuery class" /><MSHelp:Keyword Index="K" Term="Lucene.Net.Search.Spans.FieldMaskingSpanQuery class" /><MSHelp:Keyword Index="K" Term="FieldMaskingSpanQuery class, about FieldMaskingSpanQuery class" /><MSHelp:Keyword Index="F" Term="Lucene.Net.Search.Spans.FieldMaskingSpanQuery" /><MSHelp:Attr Name="HelpPriority" Value="2" /><MSHelp:Attr Name="APIType" Value="Managed" /><MSHelp:Attr Name="APILocation" Value="Lucene.Net.dll" /><MSHelp:Attr Name="APIName" Value="Lucene.Net.Search.Spans.FieldMaskingSpanQuery" /><MSHelp:Attr Name="DevLang" Value="CSharp" /><MSHelp:Attr Name="DevLang" Value="VB" /><MSHelp:Attr Name="Locale" Value="en-us" /><MSHelp:Attr Name="TopicType" Value="kbSyntax" /><MSHelp:Attr Name="TopicType" Value="apiref" /><MSHelp:Attr Name="Abstract" Value="Wrapper to allow {@link SpanQuery} objects participate in composite single-field SpanQueries by 'lying' about their search field. 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            single-field SpanQueries by 'lying' about their search field. That is, 
            the masked SpanQuery will function as normal, 
            but {@link SpanQuery#GetField()} simply hands back the value supplied 
            in this class's constructor.<p /><p />This can be used to support Queries like {@link SpanNearQuery} or 
            {@link SpanOrQuery} across different fields, which is not ordinarily 
            permitted.<p /><p />This can be useful for denormalized relational data: for example, when 
            indexing a document with conceptually many 'children': <p /><pre>
            teacherid: 1
            studentfirstname: james
            studentsurname: jones
            
            teacherid: 2
            studenfirstname: james
            studentsurname: smith
            studentfirstname: sally
            studentsurname: jones
            </pre><p />a SpanNearQuery with a slop of 0 can be applied across two 
            {@link SpanTermQuery} objects as follows:
            <pre>
            SpanQuery q1  = new SpanTermQuery(new Term("studentfirstname", "james"));
            SpanQuery q2  = new SpanTermQuery(new Term("studentsurname", "jones"));
            SpanQuery q2m new FieldMaskingSpanQuery(q2, "studentfirstname");
            Query q = new SpanNearQuery(new SpanQuery[]{q1, q2m}, -1, false);
            </pre>
            to search for 'studentfirstname:james studentsurname:jones' and find 
            teacherid 1 without matching teacherid 2 (which has a 'james' in position 0 
            and 'jones' in position 1). <p /><p />Note: as {@link #GetField()} returns the masked field, scoring will be 
            done using the norms of the field name supplied. This may lead to unexpected
            scoring behaviour.<p /></div><p /><b>Namespace:</b> <a href="c905318b-c8c8-cc5b-1ceb-e695df098f72.htm">Lucene.Net.Search.Spans</a><br /><b>Assembly:</b> <span sdata="assembly">Lucene.Net</span> (in Lucene.Net.dll) Version: 2.9.4.1<h1 class="heading"><span onclick="ExpandCollapse(syntaxToggle)" style="cursor:default;" onkeypress="ExpandCollapse_CheckKey(syntaxToggle, event)" tabindex="0"><img id="syntaxToggle" class="toggle" name="toggleSwitch" src="../icons/collapse_all.gif" />Syntax</span></h1><div id="syntaxSection" class="section" name="collapseableSection" style=""><div id="syntaxCodeBlocks" class="code"><span codeLanguage="CSharp"><table><tr><th>C#</th></tr><tr><td><pre xml:space="preserve">[<a href="http://msdn2.microsoft.com/en-us/library/bcfsa90a" target="_blank">SerializableAttribute</a>]
<span class="keyword">public</span> <span class="keyword">class</span> <span class="identifier">FieldMaskingSpanQuery</span> : <a href="2067e466-908b-f470-625a-a9444a0f6a8b.htm">SpanQuery</a></pre></td></tr></table></span><span codeLanguage="VisualBasicDeclaration"><table><tr><th>Visual Basic</th></tr><tr><td><pre xml:space="preserve">&lt;<a href="http://msdn2.microsoft.com/en-us/library/bcfsa90a" target="_blank">SerializableAttribute</a>&gt; _
<span class="keyword">Public</span> <span class="keyword">Class</span> <span class="identifier">FieldMaskingSpanQuery</span> _
	<span class="keyword">Inherits</span> <a href="2067e466-908b-f470-625a-a9444a0f6a8b.htm">SpanQuery</a></pre></td></tr></table></span><span codeLanguage="ManagedCPlusPlus"><table><tr><th>Visual C++</th></tr><tr><td><pre xml:space="preserve">[<a href="http://msdn2.microsoft.com/en-us/library/bcfsa90a" target="_blank">SerializableAttribute</a>]
<span class="keyword">public</span> <span class="keyword">ref class</span> <span class="identifier">FieldMaskingSpanQuery</span> : <span class="keyword">public</span> <a href="2067e466-908b-f470-625a-a9444a0f6a8b.htm">SpanQuery</a></pre></td></tr></table></span></div></div><h1 class="heading"><span onclick="ExpandCollapse(familyToggle)" style="cursor:default;" onkeypress="ExpandCollapse_CheckKey(familyToggle, event)" tabindex="0"><img id="familyToggle" class="toggle" name="toggleSwitch" src="../icons/collapse_all.gif" />Inheritance Hierarchy</span></h1><div id="familySection" class="section" name="collapseableSection" style=""><a href="http://msdn2.microsoft.com/en-us/library/e5kfa45b" target="_blank">System<span class="languageSpecificText"><span class="cs">.</span><span class="vb">.</span><span class="cpp">::</span><span class="nu">.</span><span class="fs">.</span></span>Object</a><br />  <a href="92f5b96d-ab32-4c16-79a2-bdc2e707f1fe.htm">Lucene.Net.Search<span class="languageSpecificText"><span class="cs">.</span><span class="vb">.</span><span class="cpp">::</span><span class="nu">.</span><span class="fs">.</span></span>Query</a><br />    <a href="2067e466-908b-f470-625a-a9444a0f6a8b.htm">Lucene.Net.Search.Spans<span class="languageSpecificText"><span class="cs">.</span><span class="vb">.</span><span class="cpp">::</span><span class="nu">.</span><span class="fs">.</span></span>SpanQuery</a><br />      <span class="selflink">Lucene.Net.Search.Spans<span class="languageSpecificText"><span class="cs">.</span><span class="vb">.</span><span class="cpp">::</span><span class="nu">.</span><span class="fs">.</span></span>FieldMaskingSpanQuery</span><br /></div><h1 class="heading"><span onclick="ExpandCollapse(seeAlsoToggle)" style="cursor:default;" onkeypress="ExpandCollapse_CheckKey(seeAlsoToggle, event)" tabindex="0"><img id="seeAlsoToggle" class="toggle" name="toggleSwitch" src="../icons/collapse_all.gif" />See Also</span></h1><div id="seeAlsoSection" class="section" name="collapseableSection" style=""><div class="seeAlsoStyle"><a href="bca05ab0-9bd0-1e39-518c-43219612ef03.htm">FieldMaskingSpanQuery Members</a></div><div class="seeAlsoStyle"><a href="c905318b-c8c8-cc5b-1ceb-e695df098f72.htm">Lucene.Net.Search.Spans Namespace</a></div></div></div><div id="footer"><div class="footerLine"><img width="100%" height="3px" src="../icons/footer.gif" alt="Footer image" title="Footer image" /></div><A NAME="feedback"></A><span id="fb" class="feedbackcss"></span></div></div></body></html>