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Diffstat (limited to 'gson/src/main/java/org/onap/policy/common/gson/JacksonMethodAdapterFactory.java')
-rw-r--r-- | gson/src/main/java/org/onap/policy/common/gson/JacksonMethodAdapterFactory.java | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/gson/src/main/java/org/onap/policy/common/gson/JacksonMethodAdapterFactory.java b/gson/src/main/java/org/onap/policy/common/gson/JacksonMethodAdapterFactory.java new file mode 100644 index 00000000..1c3039f7 --- /dev/null +++ b/gson/src/main/java/org/onap/policy/common/gson/JacksonMethodAdapterFactory.java @@ -0,0 +1,202 @@ +/* + * ============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; + } + } +} |