org.apache.lucene.analysis
Class TokenStreamToAutomaton

java.lang.Object
  org.apache.lucene.analysis.TokenStreamToAutomaton

public class TokenStreamToAutomaton
extends Object

Consumes a TokenStream and creates an Automaton where the transition labels are UTF8 bytes from the TermToBytesRefAttribute. Between tokens we insert POS_SEP and for holes we insert HOLE.

Field Summary

static int	HOLE We add this arc to represent a hole.
static int	POS_SEP We create transition between two adjacent tokens.

Constructor Summary

TokenStreamToAutomaton()
Sole constructor.

Method Summary

protected BytesRef	changeToken(BytesRef in) Subclass & implement this if you need to change the token (such as escaping certain bytes) before it's turned into a graph.
Automaton	toAutomaton(TokenStream in) Pulls the graph (including PositionLengthAttribute) from the provided TokenStream, and creates the corresponding automaton where arcs are bytes from each term.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

POS_SEP

public static final int POS_SEP

We create transition between two adjacent tokens.

See Also:

Constant Field Values

HOLE

public static final int HOLE

We add this arc to represent a hole.

See Also:

Constant Field Values

Constructor Detail

TokenStreamToAutomaton

public TokenStreamToAutomaton()

Sole constructor.

Method Detail

changeToken

protected BytesRef changeToken(BytesRef in)

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

toAutomaton

public Automaton toAutomaton(TokenStream in)
                      throws IOException

Pulls the graph (including PositionLengthAttribute) from the provided TokenStream, and creates the corresponding automaton where arcs are bytes from each term.

Throws:

IOException