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| <article class="content wrap" id="_content" data-uid="Lucene.Net.Index.IndexDeletionPolicy"> |
| |
| |
| <h1 id="Lucene_Net_Index_IndexDeletionPolicy" data-uid="Lucene.Net.Index.IndexDeletionPolicy" class="text-break">Class IndexDeletionPolicy |
| </h1> |
| <div class="markdown level0 summary"><p>Expert: policy for deletion of stale <a class="xref" href="Lucene.Net.Index.IndexCommit.html">IndexCommit</a>s.</p> |
| |
| <p>Implement this interface, and pass it to one |
| of the <a class="xref" href="Lucene.Net.Index.IndexWriter.html">IndexWriter</a> or <a class="xref" href="Lucene.Net.Index.IndexReader.html">IndexReader</a> |
| constructors, to customize when older |
| point-in-time commits (<a class="xref" href="Lucene.Net.Index.IndexCommit.html">IndexCommit</a>) |
| are deleted from the index directory. The default deletion policy |
| is <a class="xref" href="Lucene.Net.Index.KeepOnlyLastCommitDeletionPolicy.html">KeepOnlyLastCommitDeletionPolicy</a>, which always |
| removes old commits as soon as a new commit is done (this |
| matches the behavior before 2.2).</p> |
| |
| <p>One expected use case for this (and the reason why it |
| was first created) is to work around problems with an |
| index directory accessed via filesystems like NFS because |
| NFS does not provide the "delete on last close" semantics |
| that Lucene's "point in time" search normally relies on. |
| By implementing a custom deletion policy, such as "a |
| commit is only removed once it has been stale for more |
| than X minutes", you can give your readers time to |
| refresh to the new commit before <a class="xref" href="Lucene.Net.Index.IndexWriter.html">IndexWriter</a> |
| removes the old commits. Note that doing so will |
| increase the storage requirements of the index. See <a target="top" href="http://issues.apache.org/jira/browse/LUCENE-710">LUCENE-710</a> |
| for details.</p> |
| |
| <p>Implementers of sub-classes should make sure that <a class="xref" href="Lucene.Net.Index.IndexDeletionPolicy.html#Lucene_Net_Index_IndexDeletionPolicy_Clone">Clone()</a> |
| returns an independent instance able to work with any other <a class="xref" href="Lucene.Net.Index.IndexWriter.html">IndexWriter</a> |
| or <a class="xref" href="Lucene.Net.Store.Directory.html">Directory</a> instance.</p> |
| </div> |
| <div class="markdown level0 conceptual"></div> |
| <div class="inheritance"> |
| <h5>Inheritance</h5> |
| <div class="level0"><span class="xref">System.Object</span></div> |
| <div class="level1"><span class="xref">IndexDeletionPolicy</span></div> |
| <div class="level2"><a class="xref" href="Lucene.Net.Index.KeepOnlyLastCommitDeletionPolicy.html">KeepOnlyLastCommitDeletionPolicy</a></div> |
| <div class="level2"><a class="xref" href="Lucene.Net.Index.NoDeletionPolicy.html">NoDeletionPolicy</a></div> |
| <div class="level2"><a class="xref" href="Lucene.Net.Index.SnapshotDeletionPolicy.html">SnapshotDeletionPolicy</a></div> |
| </div> |
| <div class="inheritedMembers"> |
| <h5>Inherited Members</h5> |
| <div> |
| <span class="xref">System.Object.Equals(System.Object)</span> |
| </div> |
| <div> |
| <span class="xref">System.Object.Equals(System.Object, System.Object)</span> |
| </div> |
| <div> |
| <span class="xref">System.Object.GetHashCode()</span> |
| </div> |
| <div> |
| <span class="xref">System.Object.GetType()</span> |
| </div> |
| <div> |
| <span class="xref">System.Object.MemberwiseClone()</span> |
| </div> |
| <div> |
| <span class="xref">System.Object.ReferenceEquals(System.Object, System.Object)</span> |
| </div> |
| <div> |
| <span class="xref">System.Object.ToString()</span> |
| </div> |
| </div> |
| <h6><strong>Namespace</strong>: <a class="xref" href="Lucene.Net.Index.html">Lucene.Net.Index</a></h6> |
| <h6><strong>Assembly</strong>: Lucene.Net.dll</h6> |
| <h5 id="Lucene_Net_Index_IndexDeletionPolicy_syntax">Syntax</h5> |
| <div class="codewrapper"> |
| <pre><code class="lang-csharp hljs">public abstract class IndexDeletionPolicy</code></pre> |
| </div> |
| <h3 id="constructors">Constructors |
| </h3> |
| <span class="small pull-right mobile-hide"> |
| <span class="divider">|</span> |
| <a href="https://github.com/apache/lucenenet/new/docs/4.8.0-beta00010/websites/apidocs/apiSpec/new?filename=Lucene_Net_Index_IndexDeletionPolicy__ctor.md&value=---%0Auid%3A%20Lucene.Net.Index.IndexDeletionPolicy.%23ctor%0Asummary%3A%20'*You%20can%20override%20summary%20for%20the%20API%20here%20using%20*MARKDOWN*%20syntax'%0A---%0A%0A*Please%20type%20below%20more%20information%20about%20this%20API%3A*%0A%0A">Improve this Doc</a> |
| </span> |
| <span class="small pull-right mobile-hide"> |
| <a href="https://github.com/NightOwl888/lucenenet/blob/release/Lucene.Net_4_8_0_beta00010/src/Lucene.Net/Index/IndexDeletionPolicy.cs/#L62">View Source</a> |
| </span> |
| <a id="Lucene_Net_Index_IndexDeletionPolicy__ctor_" data-uid="Lucene.Net.Index.IndexDeletionPolicy.#ctor*"></a> |
| <h4 id="Lucene_Net_Index_IndexDeletionPolicy__ctor" data-uid="Lucene.Net.Index.IndexDeletionPolicy.#ctor">IndexDeletionPolicy()</h4> |
| <div class="markdown level1 summary"><p>Sole constructor, typically called by sub-classes constructors. </p> |
| </div> |
| <div class="markdown level1 conceptual"></div> |
| <h5 class="decalaration">Declaration</h5> |
| <div class="codewrapper"> |
| <pre><code class="lang-csharp hljs">protected IndexDeletionPolicy()</code></pre> |
| </div> |
| <h3 id="methods">Methods |
| </h3> |
| <span class="small pull-right mobile-hide"> |
| <span class="divider">|</span> |
| <a href="https://github.com/apache/lucenenet/new/docs/4.8.0-beta00010/websites/apidocs/apiSpec/new?filename=Lucene_Net_Index_IndexDeletionPolicy_Clone.md&value=---%0Auid%3A%20Lucene.Net.Index.IndexDeletionPolicy.Clone%0Asummary%3A%20'*You%20can%20override%20summary%20for%20the%20API%20here%20using%20*MARKDOWN*%20syntax'%0A---%0A%0A*Please%20type%20below%20more%20information%20about%20this%20API%3A*%0A%0A">Improve this Doc</a> |
| </span> |
| <span class="small pull-right mobile-hide"> |
| <a href="https://github.com/NightOwl888/lucenenet/blob/release/Lucene.Net_4_8_0_beta00010/src/Lucene.Net/Index/IndexDeletionPolicy.cs/#L111">View Source</a> |
| </span> |
| <a id="Lucene_Net_Index_IndexDeletionPolicy_Clone_" data-uid="Lucene.Net.Index.IndexDeletionPolicy.Clone*"></a> |
| <h4 id="Lucene_Net_Index_IndexDeletionPolicy_Clone" data-uid="Lucene.Net.Index.IndexDeletionPolicy.Clone">Clone()</h4> |
| <div class="markdown level1 summary"></div> |
| <div class="markdown level1 conceptual"></div> |
| <h5 class="decalaration">Declaration</h5> |
| <div class="codewrapper"> |
| <pre><code class="lang-csharp hljs">public virtual object Clone()</code></pre> |
| </div> |
| <h5 class="returns">Returns</h5> |
| <table class="table table-bordered table-striped table-condensed"> |
| <thead> |
| <tr> |
| <th>Type</th> |
| <th>Description</th> |
| </tr> |
| </thead> |
| <tbody> |
| <tr> |
| <td><span class="xref">System.Object</span></td> |
| <td></td> |
| </tr> |
| </tbody> |
| </table> |
| <span class="small pull-right mobile-hide"> |
| <span class="divider">|</span> |
| <a href="https://github.com/apache/lucenenet/new/docs/4.8.0-beta00010/websites/apidocs/apiSpec/new?filename=Lucene_Net_Index_IndexDeletionPolicy_OnCommit__1_System_Collections_Generic_IList___0__.md&value=---%0Auid%3A%20Lucene.Net.Index.IndexDeletionPolicy.OnCommit%60%601(System.Collections.Generic.IList%7B%60%600%7D)%0Asummary%3A%20'*You%20can%20override%20summary%20for%20the%20API%20here%20using%20*MARKDOWN*%20syntax'%0A---%0A%0A*Please%20type%20below%20more%20information%20about%20this%20API%3A*%0A%0A">Improve this Doc</a> |
| </span> |
| <span class="small pull-right mobile-hide"> |
| <a href="https://github.com/NightOwl888/lucenenet/blob/release/Lucene.Net_4_8_0_beta00010/src/Lucene.Net/Index/IndexDeletionPolicy.cs/#L109">View Source</a> |
| </span> |
| <a id="Lucene_Net_Index_IndexDeletionPolicy_OnCommit_" data-uid="Lucene.Net.Index.IndexDeletionPolicy.OnCommit*"></a> |
| <h4 id="Lucene_Net_Index_IndexDeletionPolicy_OnCommit__1_System_Collections_Generic_IList___0__" data-uid="Lucene.Net.Index.IndexDeletionPolicy.OnCommit``1(System.Collections.Generic.IList{``0})">OnCommit<T>(IList<T>)</h4> |
| <div class="markdown level1 summary"><p>this is called each time the writer completed a commit. |
| this gives the policy a chance to remove old commit points |
| with each commit.</p> |
| |
| <p>The policy may now choose to delete old commit points |
| by calling method <a class="xref" href="Lucene.Net.Index.IndexCommit.html#Lucene_Net_Index_IndexCommit_Delete">Delete()</a> |
| of <a class="xref" href="Lucene.Net.Index.IndexCommit.html">IndexCommit</a>.</p> |
| |
| <p>This method is only called when |
| <a class="xref" href="Lucene.Net.Index.IndexWriter.html#Lucene_Net_Index_IndexWriter_Commit">Commit()</a>} or <a class="xref" href="Lucene.Net.Index.IndexWriter.html#Lucene_Net_Index_IndexWriter_Dispose">Dispose()</a> is |
| called, or possibly not at all if the |
| <a class="xref" href="Lucene.Net.Index.IndexWriter.html#Lucene_Net_Index_IndexWriter_Rollback">Rollback()</a>} method is called.</p> |
| |
| <p><u>Note:</u> the last CommitPoint is the most recent one, |
| i.e. the "front index state". Be careful not to delete it, |
| unless you know for sure what you are doing, and unless |
| you can afford to lose the index content while doing that.</p> |
| </div> |
| <div class="markdown level1 conceptual"></div> |
| <h5 class="decalaration">Declaration</h5> |
| <div class="codewrapper"> |
| <pre><code class="lang-csharp hljs">public abstract void OnCommit<T>(IList<T> commits) |
| where T : IndexCommit</code></pre> |
| </div> |
| <h5 class="parameters">Parameters</h5> |
| <table class="table table-bordered table-striped table-condensed"> |
| <thead> |
| <tr> |
| <th>Type</th> |
| <th>Name</th> |
| <th>Description</th> |
| </tr> |
| </thead> |
| <tbody> |
| <tr> |
| <td><span class="xref">System.Collections.Generic.IList</span><T></td> |
| <td><span class="parametername">commits</span></td> |
| <td><p>List of <a class="xref" href="Lucene.Net.Index.IndexCommit.html">IndexCommit</a>s, |
| sorted by age (the 0th one is the oldest commit). </p> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| <h5 class="typeParameters">Type Parameters</h5> |
| <table class="table table-bordered table-striped table-condensed"> |
| <thead> |
| <tr> |
| <th>Name</th> |
| <th>Description</th> |
| </tr> |
| </thead> |
| <tbody> |
| <tr> |
| <td><span class="parametername">T</span></td> |
| <td></td> |
| </tr> |
| </tbody> |
| </table> |
| <span class="small pull-right mobile-hide"> |
| <span class="divider">|</span> |
| <a href="https://github.com/apache/lucenenet/new/docs/4.8.0-beta00010/websites/apidocs/apiSpec/new?filename=Lucene_Net_Index_IndexDeletionPolicy_OnInit__1_System_Collections_Generic_IList___0__.md&value=---%0Auid%3A%20Lucene.Net.Index.IndexDeletionPolicy.OnInit%60%601(System.Collections.Generic.IList%7B%60%600%7D)%0Asummary%3A%20'*You%20can%20override%20summary%20for%20the%20API%20here%20using%20*MARKDOWN*%20syntax'%0A---%0A%0A*Please%20type%20below%20more%20information%20about%20this%20API%3A*%0A%0A">Improve this Doc</a> |
| </span> |
| <span class="small pull-right mobile-hide"> |
| <a href="https://github.com/NightOwl888/lucenenet/blob/release/Lucene.Net_4_8_0_beta00010/src/Lucene.Net/Index/IndexDeletionPolicy.cs/#L86">View Source</a> |
| </span> |
| <a id="Lucene_Net_Index_IndexDeletionPolicy_OnInit_" data-uid="Lucene.Net.Index.IndexDeletionPolicy.OnInit*"></a> |
| <h4 id="Lucene_Net_Index_IndexDeletionPolicy_OnInit__1_System_Collections_Generic_IList___0__" data-uid="Lucene.Net.Index.IndexDeletionPolicy.OnInit``1(System.Collections.Generic.IList{``0})">OnInit<T>(IList<T>)</h4> |
| <div class="markdown level1 summary"><p>this is called once when a writer is first |
| instantiated to give the policy a chance to remove old |
| commit points.</p> |
| |
| <p>The writer locates all index commits present in the |
| index directory and calls this method. The policy may |
| choose to delete some of the commit points, doing so by |
| calling method <a class="xref" href="Lucene.Net.Index.IndexCommit.html#Lucene_Net_Index_IndexCommit_Delete">Delete()</a>.</p> |
| |
| <p><u>Note:</u> the last CommitPoint is the most recent one, |
| i.e. the "front index state". Be careful not to delete it, |
| unless you know for sure what you are doing, and unless |
| you can afford to lose the index content while doing that.</p> |
| </div> |
| <div class="markdown level1 conceptual"></div> |
| <h5 class="decalaration">Declaration</h5> |
| <div class="codewrapper"> |
| <pre><code class="lang-csharp hljs">public abstract void OnInit<T>(IList<T> commits) |
| where T : IndexCommit</code></pre> |
| </div> |
| <h5 class="parameters">Parameters</h5> |
| <table class="table table-bordered table-striped table-condensed"> |
| <thead> |
| <tr> |
| <th>Type</th> |
| <th>Name</th> |
| <th>Description</th> |
| </tr> |
| </thead> |
| <tbody> |
| <tr> |
| <td><span class="xref">System.Collections.Generic.IList</span><T></td> |
| <td><span class="parametername">commits</span></td> |
| <td><p>List of current point-in-time commits |
| (<a class="xref" href="Lucene.Net.Index.IndexCommit.html">IndexCommit</a>), |
| sorted by age (the 0th one is the oldest commit). |
| Note that for a new index this method is invoked with |
| an empty list. </p> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| <h5 class="typeParameters">Type Parameters</h5> |
| <table class="table table-bordered table-striped table-condensed"> |
| <thead> |
| <tr> |
| <th>Name</th> |
| <th>Description</th> |
| </tr> |
| </thead> |
| <tbody> |
| <tr> |
| <td><span class="parametername">T</span></td> |
| <td></td> |
| </tr> |
| </tbody> |
| </table> |
| </article> |
| </div> |
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