Java tutorial
/** * 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 com.google.wave.api.impl; import com.google.gson.InstanceCreator; import com.google.gson.JsonArray; 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 com.google.wave.api.Blip; import com.google.wave.api.BlipData; import com.google.wave.api.OperationQueue; import com.google.wave.api.OperationRequest; import com.google.wave.api.BlipThread; import com.google.wave.api.Wavelet; import com.google.wave.api.event.Event; import com.google.wave.api.event.EventSerializationException; import com.google.wave.api.event.EventSerializer; import java.lang.reflect.Type; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Map.Entry; /** * Gson adaptor to serialize and deserialize {@link EventMessageBundle}. * * @author douwe@google.com (Douwe Osinga) */ public class EventMessageBundleGsonAdaptor implements InstanceCreator<EventMessageBundle>, JsonSerializer<EventMessageBundle>, JsonDeserializer<EventMessageBundle> { public static final String EVENTS_TAG = "events"; public static final String WAVELET_TAG = "wavelet"; public static final String BLIPS_TAG = "blips"; public static final String THREADS_TAG = "threads"; private static final String PROXYING_FOR_TAG = "proxyingFor"; private static final String ROBOT_ADDRESS_TAG = "robotAddress"; private static final String RPC_SERVER_URL_TAG = "rpcServerUrl"; @Override public EventMessageBundle createInstance(Type type) { return new EventMessageBundle("", "http://opensocial.example.com"); } @Override public JsonElement serialize(EventMessageBundle src, Type typeOfSrc, JsonSerializationContext context) { JsonObject result = new JsonObject(); JsonArray events = new JsonArray(); for (Event event : src.getEvents()) { try { events.add(EventSerializer.serialize(event, context)); } catch (EventSerializationException e) { throw new JsonParseException(e); } } result.add(EVENTS_TAG, events); result.add(WAVELET_TAG, context.serialize(src.getWaveletData())); result.add(BLIPS_TAG, context.serialize(src.getBlipData())); result.add(THREADS_TAG, context.serialize(src.getThreads())); result.addProperty(ROBOT_ADDRESS_TAG, src.getRobotAddress()); String proxyingFor = src.getProxyingFor(); if (proxyingFor != null && !proxyingFor.isEmpty()) { result.addProperty(PROXYING_FOR_TAG, proxyingFor); } String rpcServerUrl = src.getRpcServerUrl(); if (rpcServerUrl != null && !rpcServerUrl.isEmpty()) { result.addProperty(RPC_SERVER_URL_TAG, rpcServerUrl); } return result; } @Override public EventMessageBundle deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException { JsonObject jsonObj = json.getAsJsonObject(); String robotAddress = jsonObj.get(ROBOT_ADDRESS_TAG).getAsString(); String rpcServerUrl = ""; if (jsonObj.has(RPC_SERVER_URL_TAG)) { rpcServerUrl = jsonObj.get(RPC_SERVER_URL_TAG).getAsString(); } EventMessageBundle result = new EventMessageBundle(robotAddress, rpcServerUrl); OperationQueue operationQueue; if (jsonObj.has(PROXYING_FOR_TAG)) { result.setProxyingFor(jsonObj.get(PROXYING_FOR_TAG).getAsString()); operationQueue = new OperationQueue(new ArrayList<OperationRequest>(), result.getProxyingFor()); } else { operationQueue = new OperationQueue(); } // Deserialize wavelet. WaveletData waveletData = context.deserialize(jsonObj.get(WAVELET_TAG), WaveletData.class); result.setWaveletData(waveletData); Map<String, Blip> blips = new HashMap<String, Blip>(); Map<String, BlipThread> threads = new HashMap<String, BlipThread>(); Wavelet wavelet = Wavelet.deserialize(operationQueue, blips, threads, waveletData); wavelet.setRobotAddress(robotAddress); result.setWavelet(wavelet); // Deserialize threads. Map<String, BlipThread> tempThreads = context.deserialize(jsonObj.get(THREADS_TAG), GsonFactory.THREAD_MAP_TYPE); for (Entry<String, BlipThread> entry : tempThreads.entrySet()) { BlipThread thread = entry.getValue(); threads.put(entry.getKey(), new BlipThread(thread.getId(), thread.getLocation(), thread.getBlipIds(), blips)); } // Deserialize blips. Map<String, BlipData> blipDatas = context.deserialize(jsonObj.get(BLIPS_TAG), GsonFactory.BLIP_MAP_TYPE); result.setBlipData(blipDatas); for (Entry<String, BlipData> entry : blipDatas.entrySet()) { blips.put(entry.getKey(), Blip.deserialize(operationQueue, wavelet, entry.getValue())); } // Deserialize events. JsonArray eventsArray = jsonObj.get(EVENTS_TAG).getAsJsonArray(); List<Event> events = new ArrayList<Event>(eventsArray.size()); for (JsonElement element : eventsArray) { JsonObject eventObject = element.getAsJsonObject(); try { events.add(EventSerializer.deserialize(wavelet, result, eventObject, context)); } catch (EventSerializationException e) { throw new JsonParseException(e.getMessage()); } } result.setEvents(events); return result; } }