Class LemmatizerAnnotator

java.lang.Object

opennlp.tools.lemmatizer.LemmatizerAnnotator

All Implemented Interfaces:

opennlp.tools.document.DocumentAnnotator

public final class LemmatizerAnnotator
extends Object
implements opennlp.tools.document.DocumentAnnotator

Adapts a Lemmatizer to the document pipeline: reads Layers.SENTENCES, Layers.TOKENS, and Layers.POS_TAGS and provides LEMMAS, one annotation per token on the token's span.

Each sentence is lemmatized separately, the way the lemmatizer contract expects its input, so lemmatization decisions never cross a sentence boundary. Token spans already refer to the original document text, so only the token and tag sequences handed to the lemmatizer are sliced per sentence; the produced lemma layer stays aligned with Layers.TOKENS by position.

Since:

3.0.0

Field Summary

Fields

Modifier and Type	Field	Description
static final opennlp.tools.document.LayerKey<String>	LEMMAS	The lemma layer.

Constructor Summary

Constructors

Constructor	Description
LemmatizerAnnotator(opennlp.tools.lemmatizer.Lemmatizer lemmatizer)	Initializes the adapter.

Method Summary

Modifier and Type	Method	Description
opennlp.tools.document.Document	annotate(opennlp.tools.document.Document document)	Lemmatizes the document sentence by sentence and adds the LEMMAS layer.
Set<opennlp.tools.document.LayerKey<?>>	provides()
Set<opennlp.tools.document.LayerKey<?>>	requires()
String	toString()	Returns the adapter's simple class name, which names it in pipeline validation messages.

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

LEMMAS

public static final opennlp.tools.document.LayerKey<String> LEMMAS

The lemma layer. It is aligned with the token layer by position, and each annotation carries the lemma of its token on that token's span.

Constructor Details

LemmatizerAnnotator

public LemmatizerAnnotator(opennlp.tools.lemmatizer.Lemmatizer lemmatizer)

Initializes the adapter.

Parameters:

lemmatizer - The lemmatizer to delegate to. Must not be null.

Throws:

IllegalArgumentException - Thrown if lemmatizer is null.

Method Details

annotate

public opennlp.tools.document.Document annotate(opennlp.tools.document.Document document)

Lemmatizes the document sentence by sentence and adds the LEMMAS layer.

For every sentence, the tokens whose spans lie inside the sentence span are lemmatized as one sequence together with their tags, and each lemma is emitted on its token's span. The required layers must be present, but they may be empty: a document without sentences or tokens yields a present-but-empty lemma layer, and a sentence containing no tokens contributes nothing.

Specified by:

annotate in interface opennlp.tools.document.DocumentAnnotator

Parameters:

document - The document to annotate. Must not be null and must carry the Layers.SENTENCES and Layers.TOKENS layers and a Layers.POS_TAGS layer with exactly one tag per token, with every token lying inside a sentence.

Returns:

A new Document with the LEMMAS layer added. Never null.

Throws:

IllegalArgumentException - Thrown if document is null, the sentence layer, the token layer, or the tag layer is absent, the tag layer does not have exactly one tag per token, a token lies outside every sentence, or the lemmatizer does not return one lemma per token of a sentence.

requires

public Set<opennlp.tools.document.LayerKey<?>> requires()

Specified by:

requires in interface opennlp.tools.document.DocumentAnnotator

provides

public Set<opennlp.tools.document.LayerKey<?>> provides()

Specified by:

provides in interface opennlp.tools.document.DocumentAnnotator

toString

public String toString()

Returns the adapter's simple class name, which names it in pipeline validation messages.

Overrides:

toString in class Object

Returns:

the adapter's simple class name, which names it in pipeline validation messages