Proxy Pattern ayangxu 2016/01/07 

A proxy, in its most general form, is a class functioning as an interface to something else. 

Network (retrofit) 

REST API interface WRLoginService {
 @JSONEncoded
 @POST("/login")
 Observable login(
 @JSONField("code") String code,
 @JSONField("deviceId") String deviceId,
 @JSONField("wxToken") Integer wxToken
 );
 } 

REST API interface WRLoginService {
 @JSONEncoded
 @POST("/login")
 Observable login(
 @JSONField("code") String code,
 @JSONField("deviceId") String deviceId,
 @JSONField("wxToken") Integer wxToken
 );
 } LoginInfo loginInfo = RestAdapter#create(WRLoginService.class).login(/** */); 

REST API interface WRLoginService {
 @JSONEncoded
 @POST("/login")
 Observable login(
 @JSONField("code") String code,
 @JSONField("deviceId") String deviceId,
 @JSONField("wxToken") Integer wxToken
 );
 } LoginInfo loginInfo = RestAdapter#create(WRLoginService.class).login(/** */); login() 构造URL 发请求 JSON 反序列列化 

EventBus (Watcher) 

EventBus 是什什么 • 发布-订阅模型（Publish - Subscribe） • guava/EventBus • greenrobot/EventBus • square/otto • moai/Watcher 

// Define events: public class MessageEvent { /* Additional fields if needed */ } // Prepare subscribers: eventBus.register(this); public void onEvent(AnyEventType event) { /* Do something */ }; // Post events: eventBus.post(event); greenrobot/EventBus 

// Define events: public class MessageEvent { /* Additional fields if needed */ } // Prepare subscribers: eventBus.register(this); public void onEvent(AnyEventType event) { /* Do something */ }; // Post events: eventBus.post(event); greenrobot/EventBus // Define events: public class MessageEvent { /* Additional fields if needed */ } // Prepare subscribers: eventBus.register(this); public void onEvent(AnyEventType event) { /* Do something */ }; // Post events: eventBus.post(event); 

Bus bus = new Bus(); bus.post(new AnswerAvailableEvent(42)); @Subscribe public void answerAvailable(AnswerAvailableEvent event) { // TODO: React to the event somehow! } bus.register(this); @Produce public AnswerAvailableEvent produceAnswer() { // Assuming 'lastAnswer' exists. return new AnswerAvailableEvent(this.lastAnswer); } square/otto 

Bus bus = new Bus(); bus.post(new AnswerAvailableEvent(42)); @Subscribe public void answerAvailable(AnswerAvailableEvent event) { // TODO: React to the event somehow! } bus.register(this); @Produce public AnswerAvailableEvent produceAnswer() { // Assuming 'lastAnswer' exists. return new AnswerAvailableEvent(this.lastAnswer); } square/otto Bus bus = new Bus(); bus.post(new AnswerAvailableEvent(42)); @Subscribe public void answerAvailable(AnswerAvailableEvent event) { // TODO: React to the event somehow! } bus.register(this); @Produce public AnswerAvailableEvent produceAnswer() { // Assuming 'lastAnswer' exists. return new AnswerAvailableEvent(this.lastAnswer); } 

// Define an Event public interface PushWatcher extents Watchers.Watcher { void notify(Message message); } // Publishing an Event Watchers.of(PushWatcher.class).notify(message); // Subscribing to an Event public class MyFragment extends Fragment implement PushWatcher { public void notify(Message message) { } public void onStart() { Watchers.bind(this); } } Watcher 

// Define an Event public interface PushWatcher extents Watchers.Watcher { void notify(Message message); } // Publishing an Event Watchers.of(PushWatcher.class).notify(message); // Subscribing to an Event public class MyFragment extends Fragment implement PushWatcher { public void notify(Message message) { } public void onStart() { Watchers.bind(this); } } Watcher // Define an Event public interface PushWatcher extents Watchers.Watcher { void notify(Message message); } // Publishing an Event Watchers.of(PushWatcher.class).notify(message); // Subscribing to an Event public class MyFragment extends Fragment implement PushWatcher { public void notify(Message message) { } public void onStart() { Watchers.bind(this); } } 

Watchers.of(PushWatcher.class).notify(message); 调⽤用委托 

Watchers.of(PushWatcher.class).notify(message); 调⽤用委托 Watchers.of(PushWatcher.class).notify(message); 

调⽤用委托 Watchers.of(PushWatcher.class).notify(message); EventBus 

调⽤用委托 Watchers.of(PushWatcher.class).notify(message); EventBus 事件类别 

调⽤用委托 Watchers.of(PushWatcher.class).notify(message); EventBus 事件类别 事件动作 

调⽤用委托 Watchers.of(PushWatcher.class).notify(message); EventBus 事件类别 事件动作 动作上下⽂文 

Proxy.newProxyInstance( clazz.getClassLoader(), new Class[] { clazz }, new WatcherHandler(clazz) ) 调⽤用委托 

Proxy.newProxyInstance( clazz.getClassLoader(), new Class[] { clazz }, new WatcherHandler(clazz) ) 调⽤用委托 Proxy.newProxyInstance( clazz.getClassLoader(), new Class[] { clazz }, new WatcherHandler(clazz) ) 

WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class clazz;
 WatcherHandler(Class clazz) {
 this.clazz = clazz;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 instance.trigger(clazz, method, args);
 return null;
 }
 } 

WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class clazz;
 WatcherHandler(Class clazz) {
 this.clazz = clazz;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 instance.trigger(clazz, method, args);
 return null;
 }
 } static class WatcherHandler implements InvocationHandler {
 private final Class clazz;
 WatcherHandler(Class clazz) {
 this.clazz = clazz;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 instance.trigger(clazz, method, args);
 return null;
 }
 } EventBus 

WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class clazz;
 WatcherHandler(Class clazz) {
 this.clazz = clazz;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 instance.trigger(clazz, method, args);
 return null;
 }
 } static class WatcherHandler implements InvocationHandler {
 private final Class clazz;
 WatcherHandler(Class clazz) {
 this.clazz = clazz;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 instance.trigger(clazz, method, args);
 return null;
 }
 } EventBus 事件类别 

WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class clazz;
 WatcherHandler(Class clazz) {
 this.clazz = clazz;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 instance.trigger(clazz, method, args);
 return null;
 }
 } static class WatcherHandler implements InvocationHandler {
 private final Class clazz;
 WatcherHandler(Class clazz) {
 this.clazz = clazz;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 instance.trigger(clazz, method, args);
 return null;
 }
 } EventBus 事件类别 事件动作 

WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class clazz;
 WatcherHandler(Class clazz) {
 this.clazz = clazz;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 instance.trigger(clazz, method, args);
 return null;
 }
 } static class WatcherHandler implements InvocationHandler {
 private final Class clazz;
 WatcherHandler(Class clazz) {
 this.clazz = clazz;
 }
 
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 instance.trigger(clazz, method, args);
 return null;
 }
 } EventBus 事件类别 事件动作 动作上下⽂文 

// Define an Event public interface PushWatcher extents Watchers.Watcher { void notify(Message message); } // Publishing an Event Watchers.of(PushWatcher.class).notify(message); // Subscribing to an Event public class MyFragment extends Fragment implement PushWatcher { public void notify(Message message) { } public void onStart() { Watchers.bind(this); } } 类型安全 & 重构 

// Define an Event public interface PushWatcher extents Watchers.Watcher { void notify(Message message); } // Publishing an Event Watchers.of(PushWatcher.class).notify(message); // Subscribing to an Event public class MyFragment extends Fragment implement PushWatcher { public void notify(Message message) { } public void onStart() { Watchers.bind(this); } } 类型安全 & 重构 // Define an Event public interface PushWatcher extents Watchers.Watcher { void notify(Message message); } // Publishing an Event Watchers.of(PushWatcher.class).notify(message); // Subscribing to an Event public class MyFragment extends Fragment implement PushWatcher { public void notify(Message message) { } public void onStart() { Watchers.bind(this); } } 

A/B Testing (Feature) 

功能定义 public interface Https extends Feature {
 String schema();
 } 

两种实现 @BooleanValue(true) public static class HttpsOn implements Https {
 @Override
 public String schema() {
 return "https";
 }
 }
 
 @BooleanValue(false) public static class HttpsOff implements Https {
 @Override
 public String schema() {
 return "http";
 }
 } 

使⽤用 new Endpoint() {
 @Override
 public String getUrl() {
 return Features.of(Https.class).schema()
 + "://" + Features.of(ServiceEndPoint.class).url();
 }
 }; 

开关 HttpsOn HttpsOff Https SP Server Features 

reflect.Proxy if (!c.isInterface()) {
 throw new IllegalArgumentException(c + " is not an interface");
 } 

Dexmaker https://github.com/crittercism/dexmaker 

实现部分接⼝口 @GET("/review/list")
 Observable LoadTimeLine(
 @Query("listType") int listType,
 @Query("synckey") long synckey,
 @Query("maxIdx") long maxIdx,
 @Query("count") int count
 ); 

实现部分接⼝口 public Observable LoadAllTimeLineList() {
 return LoadTimeLine(
 ReviewListType.TIMELINE.getTypeCode(),
 0,
 0l,
 LOAD_REVIEW_LIST_COUNT_AT_ONCE
 ).map(new Func1() {
 @Override
 public AllTimeLineList call(TimelineList timeLineList) {
 return new AllTimeLineList(timeLineList);
 }
 });
 } 

实现部分接⼝口 public Observable LoadFriendsTimeLineList(long synckey) {
 return LoadTimeLine(
 ReviewListType.TIMELINE_FRIEND.getTypeCode(),
 synckey,
 0l,
 LOAD_REVIEW_LIST_COUNT_AT_ONCE
 ).map(new Func1() {
 @Override
 public FriendsTimeLineList call(TimelineList timeLineList) {
 return new FriendsTimeLineList(timeLineList);
 }
 });
 } 

Factory 代理理 

Factory 代理理 okHttpClient.setSslSocketFactory(Reflections.proxy(WRApplicationContext.sharedInstance(),
 SSLSocketFactory.class, new InvocationHandler() {
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 if (method.getDeclaringClass() == Object.class) {
 return method.invoke(this, args);
 }
 method = FeatureSSLSocketFactory.class.getDeclaredMethod(
 method.getName(), method.getParameterTypes());
 return method.invoke(Features.of(FeatureSSLSocketFactory.class), args);
 }
 })); 

JavaBeanProxy 

JavaBeanProxy 需求点：设置过的值才提交（UpdateConfig） 

JavaBeanProxy 需求点：设置过的值才提交（UpdateConfig） 问题：怎么知道哪个字段被设置过？ 

JavaBeanProxy 

JavaBeanProxy JSON.toJSONString(object, new PropertyFilter() {
 @Override
 public boolean apply(Object o, String s, Object o1) {
 return JavaBeanProxy.has(o, s);
 }
 }); 

JavaBeanStorage 

JavaBeanStorage 需求点：设置落地 

JavaBeanStorage 需求点：设置落地 问题：怎么避免写⼀一堆重复代码？ 

JavaBeanStorage public void setDiscoverSyncKey(long syncKey) {
 setValue(AccountManager.getInstance().getCurrentLoginAccountId(),
 WRSettingKey.DISCOVER_SYNC_KEY, String.valueOf(syncKey));
 }
 
 public long getDiscoverSyncKey() {
 return getLongValue(WRSettingKey.DISCOVER_SYNC_KEY,
 AccountManager.getInstance().getCurrentLoginAccountId());
 } 

JavaBeanStorage public void setReadingBookId(String bookId) {
 setValue(AccountManager.getInstance().getCurrentLoginAccountId(), 
 WRSettingKey.READING_BOOK_ID, bookId);
 }
 
 public String getReadingBookId() {
 return getStringValue(WRSettingKey.READING_BOOK_ID,
 AccountManager.getInstance().getCurrentLoginAccountId());
 } 

JavaBeanStorage 

JavaBeanStorage 

Proxy 还能做什什么？