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Public Member Functions | Static Public Member Functions | Protected Member Functions
Lucene::IndexDeletionPolicy Class Referenceabstract

Policy for deletion of stale index commits. Implement this interface, and pass it to one of the IndexWriter or IndexReader constructors, to customize when older point-in-time commits are deleted from the index directory. The default deletion policy is KeepOnlyLastCommitDeletionPolicy, which always removes old commits as soon as a new commit is done (this matches the behavior before 2.2). More...

#include <IndexDeletionPolicy.h>

+ Inheritance diagram for Lucene::IndexDeletionPolicy:

Public Member Functions

virtual ~IndexDeletionPolicy ()
 
virtual String getClassName ()
 
boost::shared_ptr< IndexDeletionPolicyshared_from_this ()
 
virtual void onInit (Collection< IndexCommitPtr > commits)=0
 This is called once when a writer is first instantiated to give the policy a chance to remove old commit points.
 
virtual void onCommit (Collection< IndexCommitPtr > commits)=0
 This is called each time the writer completed a commit. This gives the policy a chance to remove old commit points with each commit.
 
- Public Member Functions inherited from Lucene::LuceneObject
virtual ~LuceneObject ()
 
virtual void initialize ()
 Called directly after instantiation to create objects that depend on this object being fully constructed.
 
virtual LuceneObjectPtr clone (const LuceneObjectPtr &other=LuceneObjectPtr())
 Return clone of this object.
 
virtual int32_t hashCode ()
 Return hash code for this object.
 
virtual bool equals (const LuceneObjectPtr &other)
 Return whether two objects are equal.
 
virtual int32_t compareTo (const LuceneObjectPtr &other)
 Compare two objects.
 
virtual String toString ()
 Returns a string representation of the object.
 
- Public Member Functions inherited from Lucene::LuceneSync
virtual ~LuceneSync ()
 
virtual SynchronizePtr getSync ()
 Return this object synchronize lock.
 
virtual LuceneSignalPtr getSignal ()
 Return this object signal.
 
virtual void lock (int32_t timeout=0)
 Lock this object using an optional timeout.
 
virtual void unlock ()
 Unlock this object.
 
virtual bool holdsLock ()
 Returns true if this object is currently locked by current thread.
 
virtual void wait (int32_t timeout=0)
 Wait for signal using an optional timeout.
 
virtual void notifyAll ()
 Notify all threads waiting for signal.
 

Static Public Member Functions

static String _getClassName ()
 

Protected Member Functions

 IndexDeletionPolicy ()
 
- Protected Member Functions inherited from Lucene::LuceneObject
 LuceneObject ()
 

Additional Inherited Members

- Protected Attributes inherited from Lucene::LuceneSync
SynchronizePtr objectLock
 
LuceneSignalPtr objectSignal
 

Detailed Description

Policy for deletion of stale index commits. Implement this interface, and pass it to one of the IndexWriter or IndexReader constructors, to customize when older point-in-time commits are deleted from the index directory. The default deletion policy is KeepOnlyLastCommitDeletionPolicy, which always removes old commits as soon as a new commit is done (this matches the behavior before 2.2).

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 IndexWriter removes the old commits. Note that doing so will increase the storage requirements of the index.

Constructor & Destructor Documentation

◆ IndexDeletionPolicy()

Lucene::IndexDeletionPolicy::IndexDeletionPolicy ( )
protected

◆ ~IndexDeletionPolicy()

virtual Lucene::IndexDeletionPolicy::~IndexDeletionPolicy ( )
virtual

Member Function Documentation

◆ _getClassName()

static String Lucene::IndexDeletionPolicy::_getClassName ( )
inlinestatic

◆ getClassName()

virtual String Lucene::IndexDeletionPolicy::getClassName ( )
inlinevirtual

◆ onCommit()

virtual void Lucene::IndexDeletionPolicy::onCommit ( Collection< IndexCommitPtr commits)
pure virtual

This is called each time the writer completed a commit. This gives the policy a chance to remove old commit points with each commit.

The policy may now choose to delete old commit points by calling method delete() of IndexCommit.

This method is only called when IndexWriter#commit or IndexWriter#close is called, or possibly not at all if the IndexWriter#rollback is called.

Note: the last CommitPoint is the most recent one, ie. 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.

Parameters
commitsList of IndexCommit, sorted by age (the 0th one is the oldest commit).

Implemented in Lucene::KeepOnlyLastCommitDeletionPolicy, and Lucene::SnapshotDeletionPolicy.

◆ onInit()

virtual void Lucene::IndexDeletionPolicy::onInit ( Collection< IndexCommitPtr commits)
pure virtual

This is called once when a writer is first instantiated to give the policy a chance to remove old commit points.

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 delete() of IndexCommit.

Note: the last CommitPoint is the most recent one, ie. 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.

Parameters
commitsList of current point-in-time commits, sorted by age (the 0th one is the oldest commit).

Implemented in Lucene::KeepOnlyLastCommitDeletionPolicy, and Lucene::SnapshotDeletionPolicy.

◆ shared_from_this()

boost::shared_ptr< IndexDeletionPolicy > Lucene::IndexDeletionPolicy::shared_from_this ( )
inline

The documentation for this class was generated from the following file:

clucene.sourceforge.net