edu.stanford.nlp.naturalli

Class RelationTripleSegmenter

java.lang.Object

edu.stanford.nlp.naturalli.RelationTripleSegmenter

public class RelationTripleSegmenter
extends java.lang.Object

This class takes a SentenceFragment and converts it to a conventional OpenIE triple, as materialized in the RelationTriple class.

Author:

Gabor Angeli

Field Summary

Fields

Modifier and Type	Field and Description
java.util.List<TokenSequencePattern>	NOUN_TOKEN_PATTERNS A set of nominal patterns, that don't require being in a coherent clause, but do require NER information.
java.util.Set<java.lang.String>	VALID_ADVERB_ARCS A set of valid arcs denoting an adverbial modifier we are interested in
java.util.Set<java.lang.String>	VALID_OBJECT_ARCS A set of valid arcs denoting an object entity we are interested in
java.util.Set<java.lang.String>	VALID_SUBJECT_ARCS A set of valid arcs denoting a subject entity we are interested in
java.util.List<SemgrexPattern>	VERB_PATTERNS A list of patterns to match relation extractions against
java.util.List<SemgrexPattern>	VP_PATTERNS A set of derivative patterns from VERB_PATTERNS that ignore the subject arc.

Constructor Summary

Constructors

Constructor and Description
RelationTripleSegmenter()
RelationTripleSegmenter(boolean allowNominalsWithoutNER) Create a new relation triple segmenter.

Method Summary

Modifier and Type	Method and Description
java.util.List<RelationTriple>	extract(SemanticGraph parse, java.util.List<CoreLabel> tokens) Extract the nominal patterns from this sentence.
protected java.util.Optional<java.util.List<IndexedWord>>	getValidAdverbChunk(SemanticGraph parse, IndexedWord root, java.util.Optional<java.lang.String> noopArc) Get the yield of a given subtree, if it is a adverb chunk.
protected java.util.Optional<java.util.List<IndexedWord>>	getValidChunk(SemanticGraph parse, IndexedWord originalRoot, java.util.Set<java.lang.String> validArcs, java.util.Optional<java.lang.String> ignoredArc)
protected java.util.Optional<java.util.List<IndexedWord>>	getValidChunk(SemanticGraph parse, IndexedWord originalRoot, java.util.Set<java.lang.String> validArcs, java.util.Optional<java.lang.String> ignoredArc, boolean allowExtraArcs)
protected java.util.Optional<java.util.List<IndexedWord>>	getValidObjectChunk(SemanticGraph parse, IndexedWord root, java.util.Optional<java.lang.String> noopArc) Get the yield of a given subtree, if it is a valid object.
protected java.util.Optional<java.util.List<IndexedWord>>	getValidSubjectChunk(SemanticGraph parse, IndexedWord root, java.util.Optional<java.lang.String> noopArc) Get the yield of a given subtree, if it is a valid subject.
java.util.Optional<RelationTriple>	segment(SemanticGraph parse, java.util.Optional<java.lang.Double> confidence) Segment the given parse tree, forcing all nodes to be consumed.
java.util.Optional<RelationTriple>	segment(SemanticGraph parse, java.util.Optional<java.lang.Double> confidence, boolean consumeAll) This is the main entry point from the Annotator.

Methods inherited from class java.lang.Object

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

Field Detail

VERB_PATTERNS

public final java.util.List<SemgrexPattern> VERB_PATTERNS

A list of patterns to match relation extractions against

VP_PATTERNS

public final java.util.List<SemgrexPattern> VP_PATTERNS

A set of derivative patterns from VERB_PATTERNS that ignore the subject arc. This is useful primarily for creating a training set for the clause splitter which emulates the behavior of the relation triple segmenter component.

NOUN_TOKEN_PATTERNS

public final java.util.List<TokenSequencePattern> NOUN_TOKEN_PATTERNS

A set of nominal patterns, that don't require being in a coherent clause, but do require NER information.

VALID_SUBJECT_ARCS

public final java.util.Set<java.lang.String> VALID_SUBJECT_ARCS

A set of valid arcs denoting a subject entity we are interested in

VALID_OBJECT_ARCS

public final java.util.Set<java.lang.String> VALID_OBJECT_ARCS

A set of valid arcs denoting an object entity we are interested in

VALID_ADVERB_ARCS

public final java.util.Set<java.lang.String> VALID_ADVERB_ARCS

A set of valid arcs denoting an adverbial modifier we are interested in

Constructor Detail

RelationTripleSegmenter

public RelationTripleSegmenter(boolean allowNominalsWithoutNER)

Create a new relation triple segmenter.

Parameters:

allowNominalsWithoutNER - If true, extract all nominal relations and not just those which are warranted based on named entity tags. For most practical applications, this greatly over-produces trivial triples.

RelationTripleSegmenter

public RelationTripleSegmenter()

See Also:

RelationTripleSegmenter(boolean)

Method Detail

extract

public java.util.List<RelationTriple> extract(SemanticGraph parse,
                                              java.util.List<CoreLabel> tokens)

Extract the nominal patterns from this sentence.

Parameters:

parse - The parse tree of the sentence to annotate.

tokens - The tokens of the sentence to annotate.

Returns:

A list of RelationTriples. Note that these do not have an associated tree with them.

See Also:

NOUN_TOKEN_PATTERNS, NOUN_DEPENDENCY_PATTERNS

getValidChunk

protected java.util.Optional<java.util.List<IndexedWord>> getValidChunk(SemanticGraph parse,
                                                                        IndexedWord originalRoot,
                                                                        java.util.Set<java.lang.String> validArcs,
                                                                        java.util.Optional<java.lang.String> ignoredArc,
                                                                        boolean allowExtraArcs)

See Also:

getValidSubjectChunk(edu.stanford.nlp.semgraph.SemanticGraph, edu.stanford.nlp.ling.IndexedWord, Optional), getValidObjectChunk(edu.stanford.nlp.semgraph.SemanticGraph, edu.stanford.nlp.ling.IndexedWord, Optional), getValidAdverbChunk(edu.stanford.nlp.semgraph.SemanticGraph, edu.stanford.nlp.ling.IndexedWord, Optional)

getValidChunk

protected java.util.Optional<java.util.List<IndexedWord>> getValidChunk(SemanticGraph parse,
                                                                        IndexedWord originalRoot,
                                                                        java.util.Set<java.lang.String> validArcs,
                                                                        java.util.Optional<java.lang.String> ignoredArc)

See Also:

getValidChunk(SemanticGraph, IndexedWord, Set, Optional, boolean)

getValidSubjectChunk

protected java.util.Optional<java.util.List<IndexedWord>> getValidSubjectChunk(SemanticGraph parse,
                                                                               IndexedWord root,
                                                                               java.util.Optional<java.lang.String> noopArc)

Get the yield of a given subtree, if it is a valid subject. Otherwise, return Optional.empty()}.

Parameters:

parse - The parse tree we are extracting a subtree from.

root - The root of the subtree.

noopArc - An optional edge type to ignore in gathering the chunk.

Returns:

If this subtree is a valid entity, we return its yield. Otherwise, we return empty.

getValidObjectChunk

protected java.util.Optional<java.util.List<IndexedWord>> getValidObjectChunk(SemanticGraph parse,
                                                                              IndexedWord root,
                                                                              java.util.Optional<java.lang.String> noopArc)

Get the yield of a given subtree, if it is a valid object. Otherwise, return Optional.empty()}.

Parameters:

parse - The parse tree we are extracting a subtree from.

root - The root of the subtree.

noopArc - An optional edge type to ignore in gathering the chunk.

Returns:

If this subtree is a valid entity, we return its yield. Otherwise, we return empty.

getValidAdverbChunk

protected java.util.Optional<java.util.List<IndexedWord>> getValidAdverbChunk(SemanticGraph parse,
                                                                              IndexedWord root,
                                                                              java.util.Optional<java.lang.String> noopArc)

Get the yield of a given subtree, if it is a adverb chunk. Otherwise, return Optional.empty()}.

Parameters:

parse - The parse tree we are extracting a subtree from.

root - The root of the subtree.

noopArc - An optional edge type to ignore in gathering the chunk.

Returns:

If this subtree is a valid adverb, we return its yield. Otherwise, we return empty.

segment

public java.util.Optional<RelationTriple> segment(SemanticGraph parse,
                                                  java.util.Optional<java.lang.Double> confidence,
                                                  boolean consumeAll)

This is the main entry point from the Annotator.

Tries to segment this sentence as a relation triple. This sentence must already match one of a few strict patterns for a valid OpenIE extraction. If it does not, then no relation triple is created. That is, this is not a relation extractor; it is just a utility to segment what is already a (subject, relation, object) triple into these three parts.

Relations are verified using semgrex expressions. For example, look at VERB_PATTERNS for a list of semgrex expressions involving verbs.

Once a relation is potentially here, this method goes through some pruning steps to eliminate invalid relations. For example, if one of the get clauses contains a NOT or similar word, we eliminate that, since the system has not been written to handle negation. Other possible eliminations are for having arcs which were not expected as part of the semgrex expression used to identify the triple.

This method will attempt to use both the verb-centric patterns and the ACL-centric patterns.

Parameters:

parse - The sentence to process, as a dependency tree.

confidence - An optional confidence to pass on to the relation triple.

consumeAll - if true, force the entire parse to be consumed by the pattern.

Returns:

A relation triple, if this sentence matches one of the patterns of a valid relation triple.

segment

public java.util.Optional<RelationTriple> segment(SemanticGraph parse,
                                                  java.util.Optional<java.lang.Double> confidence)

Segment the given parse tree, forcing all nodes to be consumed.

See Also:

segment(edu.stanford.nlp.semgraph.SemanticGraph, Optional)