Class TokenStreamToAutomaton

Consumes a TokenStream and creates an Automaton where the transition labels are UTF8 bytes (or Unicode code points if unicodeArcs is true) from the ITermToBytesRefAttribute. Between tokens we insert POS_SEP and for holes we insert HOLE.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk
Inheritance
System.Object
TokenStreamToAutomaton
Namespace: Lucene.Net.Analysis
Assembly: Lucene.Net.dll
Syntax
public class TokenStreamToAutomaton : object

Constructors

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TokenStreamToAutomaton()

Sole constructor.

Declaration
public TokenStreamToAutomaton()

Fields

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HOLE

We add this arc to represent a hole.

Declaration
public const int HOLE = null
Field Value
Type Description
System.Int32
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POS_SEP

We create transition between two adjacent tokens.

Declaration
public const int POS_SEP = null
Field Value
Type Description
System.Int32

Properties

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PreservePositionIncrements

Whether to generate holes in the automaton for missing positions, true by default.

Declaration
public virtual bool PreservePositionIncrements { get; set; }
Property Value
Type Description
System.Boolean
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UnicodeArcs

Whether to make transition labels Unicode code points instead of UTF8 bytes, false by default

Declaration
public virtual bool UnicodeArcs { get; set; }
Property Value
Type Description
System.Boolean

Methods

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ChangeToken(BytesRef)

Subclass & implement this if you need to change the token (such as escaping certain bytes) before it's turned into a graph.

Declaration
protected virtual BytesRef ChangeToken(BytesRef in)
Parameters
Type Name Description
BytesRef in
Returns
Type Description
BytesRef
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ToAutomaton(TokenStream)

Pulls the graph (including IPositionLengthAttribute from the provided TokenStream, and creates the corresponding automaton where arcs are bytes (or Unicode code points if unicodeArcs = true) from each term.

Declaration
public virtual Automaton ToAutomaton(TokenStream in)
Parameters
Type Name Description
TokenStream in
Returns
Type Description
Automaton