| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| package org.apache.twill.internal.state; |
| |
| import com.google.common.base.Charsets; |
| import com.google.common.reflect.TypeToken; |
| import com.google.gson.Gson; |
| import com.google.gson.GsonBuilder; |
| import com.google.gson.JsonDeserializationContext; |
| import com.google.gson.JsonDeserializer; |
| import com.google.gson.JsonElement; |
| import com.google.gson.JsonObject; |
| import com.google.gson.JsonParseException; |
| import com.google.gson.JsonSerializationContext; |
| import com.google.gson.JsonSerializer; |
| import org.apache.twill.api.Command; |
| |
| import java.lang.reflect.Type; |
| import java.util.Map; |
| |
| /** |
| * Gson codec for {@link Message}. |
| */ |
| public final class MessageCodec { |
| |
| private static final Type OPTIONS_TYPE = new TypeToken<Map<String, String>>() { }.getType(); |
| private static final Gson GSON = new GsonBuilder() |
| .serializeNulls() |
| .registerTypeAdapter(Message.class, new MessageAdapter()) |
| .registerTypeAdapter(Command.class, new CommandAdapter()) |
| .create(); |
| |
| /** |
| * Decodes a {@link Message} from the given byte array. |
| * @param bytes byte array to be decoded |
| * @return Message decoded or {@code null} if fails to decode. |
| */ |
| public static Message decode(byte[] bytes) { |
| if (bytes == null) { |
| return null; |
| } |
| String content = new String(bytes, Charsets.UTF_8); |
| return GSON.fromJson(content, Message.class); |
| } |
| |
| /** |
| * Encodes a {@link Message} into byte array. Revserse of {@link #decode(byte[])} method. |
| * @param message Message to be encoded |
| * @return byte array representing the encoded message. |
| */ |
| public static byte[] encode(Message message) { |
| return GSON.toJson(message, Message.class).getBytes(Charsets.UTF_8); |
| } |
| |
| /** |
| * Gson codec for {@link Message} object. |
| */ |
| private static final class MessageAdapter implements JsonSerializer<Message>, JsonDeserializer<Message> { |
| |
| @Override |
| public Message deserialize(JsonElement json, Type typeOfT, |
| JsonDeserializationContext context) throws JsonParseException { |
| JsonObject jsonObj = json.getAsJsonObject(); |
| |
| Message.Type type = Message.Type.valueOf(jsonObj.get("type").getAsString()); |
| Message.Scope scope = Message.Scope.valueOf(jsonObj.get("scope").getAsString()); |
| JsonElement name = jsonObj.get("runnableName"); |
| String runnableName = (name == null || name.isJsonNull()) ? null : name.getAsString(); |
| Command command = context.deserialize(jsonObj.get("command"), Command.class); |
| |
| return new SimpleMessage(type, scope, runnableName, command); |
| } |
| |
| @Override |
| public JsonElement serialize(Message message, Type typeOfSrc, JsonSerializationContext context) { |
| JsonObject jsonObj = new JsonObject(); |
| jsonObj.addProperty("type", message.getType().name()); |
| jsonObj.addProperty("scope", message.getScope().name()); |
| jsonObj.addProperty("runnableName", message.getRunnableName()); |
| jsonObj.add("command", context.serialize(message.getCommand(), Command.class)); |
| |
| return jsonObj; |
| } |
| } |
| |
| /** |
| * Gson codec for {@link Command} object. |
| */ |
| private static final class CommandAdapter implements JsonSerializer<Command>, JsonDeserializer<Command> { |
| |
| @Override |
| public Command deserialize(JsonElement json, Type typeOfT, |
| JsonDeserializationContext context) throws JsonParseException { |
| JsonObject jsonObj = json.getAsJsonObject(); |
| return Command.Builder.of(jsonObj.get("command").getAsString()) |
| .addOptions(context.<Map<String, String>>deserialize(jsonObj.get("options"), OPTIONS_TYPE)) |
| .build(); |
| } |
| |
| @Override |
| public JsonElement serialize(Command command, Type typeOfSrc, JsonSerializationContext context) { |
| JsonObject jsonObj = new JsonObject(); |
| jsonObj.addProperty("command", command.getCommand()); |
| jsonObj.add("options", context.serialize(command.getOptions(), OPTIONS_TYPE)); |
| return jsonObj; |
| } |
| } |
| |
| private MessageCodec() { |
| } |
| } |