EntityConfidence.java revision a6096f6c4c56c4937b52efb593d4333db301d6ad 
1/*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.view.textclassifier;
18
19import android.annotation.FloatRange;
20import android.annotation.NonNull;
21
22import com.android.internal.util.Preconditions;
23
24import java.util.ArrayList;
25import java.util.Collections;
26import java.util.Comparator;
27import java.util.HashMap;
28import java.util.List;
29import java.util.Map;
30
31/**
32 * Helper object for setting and getting entity scores for classified text.
33 *
34 * @param <T> the entity type.
35 * @hide
36 */
37final class EntityConfidence<T> {
38
39    private final Map<T, Float> mEntityConfidence = new HashMap<>();
40
41    private final Comparator<T> mEntityComparator = (e1, e2) -> {
42        float score1 = mEntityConfidence.get(e1);
43        float score2 = mEntityConfidence.get(e2);
44        if (score1 > score2) {
45            return -1;
46        }
47        if (score1 < score2) {
48            return 1;
49        }
50        return 0;
51    };
52
53    EntityConfidence() {}
54
55    EntityConfidence(@NonNull EntityConfidence<T> source) {
56        Preconditions.checkNotNull(source);
57        mEntityConfidence.putAll(source.mEntityConfidence);
58    }
59
60    /**
61     * Sets an entity type for the classified text and assigns a confidence score.
62     *
63     * @param confidenceScore a value from 0 (low confidence) to 1 (high confidence).
64     *      0 implies the entity does not exist for the classified text.
65     *      Values greater than 1 are clamped to 1.
66     */
67    public void setEntityType(
68            @NonNull T type, @FloatRange(from = 0.0, to = 1.0) float confidenceScore) {
69        Preconditions.checkNotNull(type);
70        if (confidenceScore > 0) {
71            mEntityConfidence.put(type, Math.min(1, confidenceScore));
72        } else {
73            mEntityConfidence.remove(type);
74        }
75    }
76
77    /**
78     * Returns an immutable list of entities found in the classified text ordered from
79     * high confidence to low confidence.
80     */
81    @NonNull
82    public List<T> getEntities() {
83        List<T> entities = new ArrayList<>(mEntityConfidence.size());
84        entities.addAll(mEntityConfidence.keySet());
85        entities.sort(mEntityComparator);
86        return Collections.unmodifiableList(entities);
87    }
88
89    /**
90     * Returns the confidence score for the specified entity. The value ranges from
91     * 0 (low confidence) to 1 (high confidence). 0 indicates that the entity was not found for the
92     * classified text.
93     */
94    @FloatRange(from = 0.0, to = 1.0)
95    public float getConfidenceScore(T entity) {
96        if (mEntityConfidence.containsKey(entity)) {
97            return mEntityConfidence.get(entity);
98        }
99        return 0;
100    }
101
102    @Override
103    public String toString() {
104        return mEntityConfidence.toString();
105    }
106}
107