Class LimitTokenCountFilter

This Lucene.Net.Analysis.TokenFilter limits the number of tokens while indexing. It is a replacement for the maximum field length setting inside Lucene.Net.Index.IndexWriter.

By default, this filter ignores any tokens in the wrapped Lucene.Net.Analysis.TokenStream once the limit has been reached, which can result in Reset() being called prior to IncrementToken() returning false. For most Lucene.Net.Analysis.TokenStream implementations this should be acceptable, and faster then consuming the full stream. If you are wrapping a Lucene.Net.Analysis.TokenStream which requires that the full stream of tokens be exhausted in order to function properly, use the LimitTokenCountFilter(TokenStream, int, bool) consumeAllTokens option.

Inheritance

object

AttributeSource

TokenStream

TokenFilter

LimitTokenCountFilter

Implements

IDisposable

Inherited Members

TokenFilter.End()

TokenStream.Dispose()

AttributeSource.GetAttributeFactory()

AttributeSource.GetAttributeClassesEnumerator()

AttributeSource.GetAttributeImplsEnumerator()

AttributeSource.AddAttributeImpl(Attribute)

AttributeSource.AddAttribute<T>()

AttributeSource.HasAttributes

AttributeSource.HasAttribute<T>()

AttributeSource.GetAttribute<T>()

AttributeSource.ClearAttributes()

AttributeSource.CaptureState()

AttributeSource.RestoreState(AttributeSource.State)

AttributeSource.GetHashCode()

AttributeSource.Equals(object)

AttributeSource.ReflectAsString(bool)

AttributeSource.ReflectWith(IAttributeReflector)

AttributeSource.CloneAttributes()

AttributeSource.CopyTo(AttributeSource)

AttributeSource.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Namespace: Lucene.Net.Analysis.Miscellaneous

Assembly: Lucene.Net.Analysis.Common.dll

Syntax

public sealed class LimitTokenCountFilter : TokenFilter, IDisposable

Constructors

LimitTokenCountFilter(TokenStream, int)

Build a filter that only accepts tokens up to a maximum number. This filter will not consume any tokens beyond the maxTokenCount limit

Declaration

public LimitTokenCountFilter(TokenStream @in, int maxTokenCount)

Parameters

Type	Name	Description
TokenStream	in	the stream to wrap
int	maxTokenCount	max number of tokens to produce

See Also

LimitTokenCountFilter(TokenStream, int, bool)

LimitTokenCountFilter(TokenStream, int, bool)

Build an filter that limits the maximum number of tokens per field.

Declaration

public LimitTokenCountFilter(TokenStream @in, int maxTokenCount, bool consumeAllTokens)

Parameters

Type	Name	Description
TokenStream	in	the stream to wrap
int	maxTokenCount	max number of tokens to produce
bool	consumeAllTokens	whether all tokens from the input must be consumed even if maxTokenCount is reached.

Methods

IncrementToken()

Consumers (i.e., Lucene.Net.Index.IndexWriter) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriate Lucene.Net.Util.IAttributes with the attributes of the next token.

The producer must make no assumptions about the attributes after the method has been returned: the caller may arbitrarily change it. If the producer needs to preserve the state for subsequent calls, it can use Lucene.Net.Util.AttributeSource.CaptureState() to create a copy of the current attribute state.

this method is called for every token of a document, so an efficient implementation is crucial for good performance. To avoid calls to Lucene.Net.Util.AttributeSource.AddAttribute<T>() and Lucene.Net.Util.AttributeSource.GetAttribute<T>(), references to all Lucene.Net.Util.IAttributes that this stream uses should be retrieved during instantiation.

To ensure that filters and consumers know which attributes are available, the attributes must be added during instantiation. Filters and consumers are not required to check for availability of attributes in Lucene.Net.Analysis.TokenStream.IncrementToken().

Declaration

public override bool IncrementToken()

Returns

Type	Description
bool	false for end of stream; true otherwise

Overrides

Lucene.Net.Analysis.TokenStream.IncrementToken()

Reset()

This method is called by a consumer before it begins consumption using Lucene.Net.Analysis.TokenStream.IncrementToken().

Resets this stream to a clean state. Stateful implementations must implement this method so that they can be reused, just as if they had been created fresh.

If you override this method, always call base.Reset(), otherwise some internal state will not be correctly reset (e.g., Lucene.Net.Analysis.Tokenizer will throw InvalidOperationException on further usage).

Declaration

public override void Reset()

Overrides

Lucene.Net.Analysis.TokenFilter.Reset()

Remarks

NOTE: The default implementation chains the call to the input Lucene.Net.Analysis.TokenStream, so be sure to call base.Reset() when overriding this method.

Implements

IDisposable