001/*
002 * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.tribuo.classification.sequence.viterbi;
018
019import com.oracle.labs.mlrg.olcut.config.Configurable;
020import com.oracle.labs.mlrg.olcut.provenance.ConfiguredObjectProvenance;
021import com.oracle.labs.mlrg.olcut.provenance.Provenancable;
022import org.tribuo.Feature;
023import org.tribuo.classification.Label;
024
025import java.io.Serializable;
026import java.util.List;
027
028/**
029 * A class for featurising labels from previous steps in Viterbi.
030 */
031public interface LabelFeatureExtractor extends Configurable, Provenancable<ConfiguredObjectProvenance>, Serializable {
032
033    /**
034     * Generates features based on the previously produced labels.
035     * @param previousOutcomes The previous step's labels.
036     * @param value The value to give to the features.
037     * @return Features.
038     */
039    public List<Feature> extractFeatures(List<Label> previousOutcomes, double value);
040
041}