Expert: a MergePolicy determines the sequence of primitive merge operations to be used for overall merge and optimize operations.

Whenever the segments in an index have been altered by {@link IndexWriter}, either the addition of a newly flushed segment, addition of many segments from addIndexes* calls, or a previous merge that may now need to cascade, {@link IndexWriter} invokes {@link #findMerges} to give the MergePolicy a chance to pick merges that are now required. This method returns a {@link MergeSpecification} instance describing the set of merges that should be done, or null if no merges are necessary. When IndexWriter.optimize is called, it calls {@link #findMergesForOptimize} and the MergePolicy should then return the necessary merges.

Note that the policy can return more than one merge at a time. In this case, if the writer is using {@link SerialMergeScheduler}, the merges will be run sequentially but if it is using {@link ConcurrentMergeScheduler} they will be run concurrently.

The default MergePolicy is {@link LogByteSizeMergePolicy}.

NOTE: This API is new and still experimental (subject to change suddenly in the next release)

NOTE: This class typically requires access to package-private APIs (e.g.

CopyC#
SegmentInfos
) to do its job; if you implement your own MergePolicy, you'll need to put it in package Lucene.Net.Index in order to use these APIs.

The MergePolicy..::..MergeException type exposes the following members.

Constructors

Methods

  NameDescription
Public methodEquals
Determines whether the specified Object is equal to the current Object.
(Inherited from Object.)
Protected methodFinalize
Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection.
(Inherited from Object.)
Public methodGetBaseException
When overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.
(Inherited from Exception.)
Public methodGetDirectory
Returns the {@link Directory} of the index that hit the exception.
Public methodGetHashCode
Serves as a hash function for a particular type.
(Inherited from Object.)
Public methodGetObjectData
When overridden in a derived class, sets the SerializationInfo with information about the exception.
(Inherited from Exception.)
Public methodGetType
Gets the runtime type of the current instance.
(Inherited from Exception.)
Protected methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Public methodToString
Creates and returns a string representation of the current exception.
(Inherited from Exception.)

Properties

  NameDescription
Public propertyData
Gets a collection of key/value pairs that provide additional user-defined information about the exception.
(Inherited from Exception.)
Public propertyHelpLink
Gets or sets a link to the help file associated with this exception.
(Inherited from Exception.)
Protected propertyHResult
Gets or sets HRESULT, a coded numerical value that is assigned to a specific exception.
(Inherited from Exception.)
Public propertyInnerException
Gets the Exception instance that caused the current exception.
(Inherited from Exception.)
Public propertyMessage
Gets a message that describes the current exception.
(Inherited from Exception.)
Public propertySource
Gets or sets the name of the application or the object that causes the error.
(Inherited from Exception.)
Public propertyStackTrace
Gets a string representation of the immediate frames on the call stack.
(Inherited from Exception.)
Public propertyTargetSite
Gets the method that throws the current exception.
(Inherited from Exception.)

Events

  NameDescription
Protected eventSerializeObjectState
Occurs when an exception is serialized to create an exception state object that contains serialized data about the exception.
(Inherited from Exception.)

See Also