EntityConfidence.java revision 0d9fbb9bd15fb1c6eae171d316a2de65aaffeb48 
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;
21import android.os.Parcel;
22import android.os.Parcelable;
23import android.util.ArrayMap;
24
25import com.android.internal.util.Preconditions;
26
27import java.util.ArrayList;
28import java.util.Collections;
29import java.util.List;
30import java.util.Map;
31
32/**
33 * Helper object for setting and getting entity scores for classified text.
34 *
35 * @hide
36 */
37final class EntityConfidence implements Parcelable {
38
39    private final ArrayMap<String, Float> mEntityConfidence = new ArrayMap<>();
40    private final ArrayList<String> mSortedEntities = new ArrayList<>();
41
42    EntityConfidence() {}
43
44    EntityConfidence(@NonNull EntityConfidence source) {
45        Preconditions.checkNotNull(source);
46        mEntityConfidence.putAll(source.mEntityConfidence);
47        mSortedEntities.addAll(source.mSortedEntities);
48    }
49
50    /**
51     * Constructs an EntityConfidence from a map of entity to confidence.
52     *
53     * Map entries that have 0 confidence are removed, and values greater than 1 are clamped to 1.
54     *
55     * @param source a map from entity to a confidence value in the range 0 (low confidence) to
56     *               1 (high confidence).
57     */
58    EntityConfidence(@NonNull Map<String, Float> source) {
59        Preconditions.checkNotNull(source);
60
61        // Prune non-existent entities and clamp to 1.
62        mEntityConfidence.ensureCapacity(source.size());
63        for (Map.Entry<String, Float> it : source.entrySet()) {
64            if (it.getValue() <= 0) continue;
65            mEntityConfidence.put(it.getKey(), Math.min(1, it.getValue()));
66        }
67        resetSortedEntitiesFromMap();
68    }
69
70    /**
71     * Returns an immutable list of entities found in the classified text ordered from
72     * high confidence to low confidence.
73     */
74    @NonNull
75    public List<String> getEntities() {
76        return Collections.unmodifiableList(mSortedEntities);
77    }
78
79    /**
80     * Returns the confidence score for the specified entity. The value ranges from
81     * 0 (low confidence) to 1 (high confidence). 0 indicates that the entity was not found for the
82     * classified text.
83     */
84    @FloatRange(from = 0.0, to = 1.0)
85    public float getConfidenceScore(String entity) {
86        if (mEntityConfidence.containsKey(entity)) {
87            return mEntityConfidence.get(entity);
88        }
89        return 0;
90    }
91
92    @Override
93    public String toString() {
94        return mEntityConfidence.toString();
95    }
96
97    @Override
98    public int describeContents() {
99        return 0;
100    }
101
102    @Override
103    public void writeToParcel(Parcel dest, int flags) {
104        dest.writeInt(mEntityConfidence.size());
105        for (Map.Entry<String, Float> entry : mEntityConfidence.entrySet()) {
106            dest.writeString(entry.getKey());
107            dest.writeFloat(entry.getValue());
108        }
109    }
110
111    public static final Parcelable.Creator<EntityConfidence> CREATOR =
112            new Parcelable.Creator<EntityConfidence>() {
113                @Override
114                public EntityConfidence createFromParcel(Parcel in) {
115                    return new EntityConfidence(in);
116                }
117
118                @Override
119                public EntityConfidence[] newArray(int size) {
120                    return new EntityConfidence[size];
121                }
122            };
123
124    private EntityConfidence(Parcel in) {
125        final int numEntities = in.readInt();
126        mEntityConfidence.ensureCapacity(numEntities);
127        for (int i = 0; i < numEntities; ++i) {
128            mEntityConfidence.put(in.readString(), in.readFloat());
129        }
130        resetSortedEntitiesFromMap();
131    }
132
133    private void resetSortedEntitiesFromMap() {
134        mSortedEntities.clear();
135        mSortedEntities.ensureCapacity(mEntityConfidence.size());
136        mSortedEntities.addAll(mEntityConfidence.keySet());
137        mSortedEntities.sort((e1, e2) -> {
138            float score1 = mEntityConfidence.get(e1);
139            float score2 = mEntityConfidence.get(e2);
140            return Float.compare(score2, score1);
141        });
142    }
143}
144