aboutsummaryrefslogtreecommitdiffstats
path: root/gson/src/main/java/org/onap/policy/common/gson/JacksonMethodAdapterFactory.java
blob: 1c3039f784cbdfea54f80bcd0c8d45c067c6dd14 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
/*
 * ============LICENSE_START=======================================================
 * ONAP
 * ================================================================================
 * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============LICENSE_END=========================================================
 */

package org.onap.policy.common.gson;

import com.google.gson.Gson;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.onap.policy.common.gson.internal.AnyGetterSerializer;
import org.onap.policy.common.gson.internal.AnySetterDeserializer;
import org.onap.policy.common.gson.internal.ClassWalker;
import org.onap.policy.common.gson.internal.Deserializer;
import org.onap.policy.common.gson.internal.MethodDeserializer;
import org.onap.policy.common.gson.internal.MethodSerializer;
import org.onap.policy.common.gson.internal.Serializer;

/**
 * Factory that serializes/deserializes class methods following the normal behavior of
 * jackson. Supports the following annotations:
 * <ul>
 * <li>GsonJsonIgnore</li>
 * <li>GsonJsonProperty</li>
 * <li>GsonJsonAnyGetter</li>
 * <li>GsonJsonAnySetter</li>
 * </ul>
 */
public class JacksonMethodAdapterFactory implements TypeAdapterFactory {

    @Override
    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
        Class<? super T> clazz = type.getRawType();

        if (!JacksonExclusionStrategy.isManaged(clazz)) {
            return null;
        }

        ClassWalker data = new ClassWalker();
        data.walkClassHierarchy(clazz);

        if (data.getInProps(Method.class).isEmpty() && data.getOutProps(Method.class).isEmpty()) {
            if (data.getAnyGetter() == null && data.getAnySetter() == null) {
                // no methods to serialize
                return null;
            }
        }

        return new JacksonMethodAdapter<>(gson, data, gson.getDelegateAdapter(this, type));
    }

    /**
     * Adapter for a single class.
     *
     * @param <T> type of class on which the adapter works
     */
    private static class JacksonMethodAdapter<T> extends TypeAdapter<T> {

        /**
         * Used to create an object of the given class.
         */
        private final TypeAdapter<T> delegate;

        /**
         * Used to serialize/deserialize a JsonElement.
         */
        private final TypeAdapter<JsonElement> elementAdapter;

        /**
         * Serializers for each item within the object.
         */
        private final Serializer[] serializers;

        /**
         * Deserializers for each item within the object.
         */
        private final Deserializer[] deserializers;

        /**
         * Constructs the object.
         *
         * @param gson the associated gson object
         * @param data data used to configure the adapter
         * @param delegate default constructor for the type
         */
        public JacksonMethodAdapter(Gson gson, ClassWalker data, TypeAdapter<T> delegate) {
            this.delegate = delegate;

            this.elementAdapter = gson.getAdapter(JsonElement.class);

            Set<String> unliftedProps = new HashSet<>();
            unliftedProps.addAll(data.getInNotIgnored());
            unliftedProps.addAll(data.getOutNotIgnored());

            // create serializers
            this.serializers = makeSerializers(gson, data, unliftedProps).toArray(new Serializer[0]);

            // create deserializers
            this.deserializers = makeDeserializers(gson, data, unliftedProps).toArray(new Deserializer[0]);
        }

        /**
         * Creates a complete list of serializers.
         *
         * @param gson the associated gson object
         * @param data data used to configure the serializers
         * @param unliftedProps properties that should not be lowered by "any-getters"
         * @return a list of all serializers
         */
        private List<Serializer> makeSerializers(Gson gson, ClassWalker data, Set<String> unliftedProps) {
            List<Serializer> ser = new ArrayList<Serializer>();

            if (data.getAnyGetter() != null) {
                ser.add(new AnyGetterSerializer(gson, unliftedProps, data.getAnyGetter()));
            }

            data.getOutProps(Method.class).forEach(method -> ser.add(new MethodSerializer(gson, method)));

            return ser;
        }

        /**
         * Creates a complete list of deserializers.
         *
         * @param gson the associated gson object
         * @param data data used to configure the deserializers
         * @param unliftedProps properties that should not be lifted by "any-setters"
         * @return a list of all deserializers
         */
        private List<Deserializer> makeDeserializers(Gson gson, ClassWalker data, Set<String> unliftedProps) {
            List<Deserializer> deser = new ArrayList<Deserializer>();

            if (data.getAnySetter() != null) {
                deser.add(new AnySetterDeserializer(gson, unliftedProps, data.getAnySetter()));
            }

            data.getInProps(Method.class).forEach(method -> deser.add(new MethodDeserializer(gson, method)));

            return deser;
        }

        @Override
        public void write(JsonWriter out, T value) throws IOException {
            JsonElement tree = delegate.toJsonTree(value);

            if (tree.isJsonObject()) {
                JsonObject jsonObj = tree.getAsJsonObject();

                // serialize each item from the value into the target tree
                for (Serializer serializer : serializers) {
                    serializer.addToTree(value, jsonObj);
                }
            }

            elementAdapter.write(out, tree);
        }

        @Override
        public T read(JsonReader in) throws IOException {
            JsonElement tree = elementAdapter.read(in);

            T object = delegate.fromJsonTree(tree);

            if (tree.isJsonObject()) {
                JsonObject jsonObj = tree.getAsJsonObject();

                // deserialize each item from the tree into the target object
                for (Deserializer dser : deserializers) {
                    dser.getFromTree(jsonObj, object);
                }
            }

            return object;
        }
    }
}