Proxy Pattern

讲述了代理模式在 App 开发过程中的应用，解耦调用和实现。

Transcript

1. Proxy Pattern ayangxu 2016/01/07
2. A proxy, in its most general form, is a class functioning as an interface to something else.
3. Network (retrofit)
4. REST API interface WRLoginService {
 @JSONEncoded
 @POST("/login")
 Observable<LoginInfo> login(
 @JSONField("code") String code,
 @JSONField("deviceId") String deviceId,
 @JSONField("wxToken") Integer wxToken
 );
 }
5. REST API interface WRLoginService {
 @JSONEncoded
 @POST("/login")
 Observable<LoginInfo> login(
 @JSONField("code") String code,
 @JSONField("deviceId") String deviceId,
 @JSONField("wxToken") Integer wxToken
 );
 } LoginInfo loginInfo = RestAdapter#create(WRLoginService.class).login(/** */);
6. REST API interface WRLoginService {
 @JSONEncoded
 @POST("/login")
 Observable<LoginInfo> 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
7. EventBus (Watcher)
8. EventBus 是什什么 • 发布-订阅模型（Publish - Subscribe） • guava/EventBus • greenrobot/EventBus • square/otto • moai/Watcher
9. // 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
10. // 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);
11. 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
12. 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); }
13. // 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
14. // 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); } }
15. Watchers.of(PushWatcher.class).notify(message); 调⽤用委托
16. Watchers.of(PushWatcher.class).notify(message); 调⽤用委托 Watchers.of(PushWatcher.class).notify(message);
17. 调⽤用委托 Watchers.of(PushWatcher.class).notify(message); EventBus
18. 调⽤用委托 Watchers.of(PushWatcher.class).notify(message); EventBus 事件类别
19. 调⽤用委托 Watchers.of(PushWatcher.class).notify(message); EventBus 事件类别 事件动作
20. 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
21. Proxy.newProxyInstance( clazz.getClassLoader(), new Class[] { clazz }, new WatcherHandler(clazz) ) 调⽤用委托
22. 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) )
23. WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class<? extends Watcher> clazz;
 WatcherHandler(Class<? extends Watcher> 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;
 }
 }
24. WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class<? extends Watcher> clazz;
 WatcherHandler(Class<? extends Watcher> 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<? extends Watcher> clazz;
 WatcherHandler(Class<? extends Watcher> 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
25. WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class<? extends Watcher> clazz;
 WatcherHandler(Class<? extends Watcher> 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<? extends Watcher> clazz;
 WatcherHandler(Class<? extends Watcher> 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
26. WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class<? extends Watcher> clazz;
 WatcherHandler(Class<? extends Watcher> 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<? extends Watcher> clazz;
 WatcherHandler(Class<? extends Watcher> 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
27. WatcherHandler static class WatcherHandler implements InvocationHandler {
 private final Class<? extends Watcher> clazz;
 WatcherHandler(Class<? extends Watcher> 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<? extends Watcher> clazz;
 WatcherHandler(Class<? extends Watcher> 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
28. // 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
29. // 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); } }
30. A/B Testing (Feature)
31. 功能定义 public interface Https extends Feature {
 String schema();
 }
32. 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";
 }
 }
33. 使⽤用 new Endpoint() {
 @Override
 public String getUrl() {
 return Features.of(Https.class).schema()
 + "://" + Features.of(ServiceEndPoint.class).url();
 }
 };
34. 开关 HttpsOn HttpsOff Https SP Server Features
35. reflect.Proxy if (!c.isInterface()) {
 throw new IllegalArgumentException(c + " is not an interface");
 }
36. Dexmaker https://github.com/crittercism/dexmaker
37. 实现部分接⼝口 @GET("/review/list")
 Observable<TimelineList> LoadTimeLine(
 @Query("listType") int listType,
 @Query("synckey") long synckey,
 @Query("maxIdx") long maxIdx,
 @Query("count") int count
 );
38. 实现部分接⼝口 public Observable<AllTimeLineList> LoadAllTimeLineList() {
 return LoadTimeLine(
 ReviewListType.TIMELINE.getTypeCode(),
 0,
 0l,
 LOAD_REVIEW_LIST_COUNT_AT_ONCE
 ).map(new Func1<TimelineList, AllTimeLineList>() {
 @Override
 public AllTimeLineList call(TimelineList timeLineList) {
 return new AllTimeLineList(timeLineList);
 }
 });
 }
39. 实现部分接⼝口 public Observable<FriendsTimeLineList> LoadFriendsTimeLineList(long synckey) {
 return LoadTimeLine(
 ReviewListType.TIMELINE_FRIEND.getTypeCode(),
 synckey,
 0l,
 LOAD_REVIEW_LIST_COUNT_AT_ONCE
 ).map(new Func1<TimelineList, FriendsTimeLineList>() {
 @Override
 public FriendsTimeLineList call(TimelineList timeLineList) {
 return new FriendsTimeLineList(timeLineList);
 }
 });
 }
40. Factory 代理理
41. 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);
 }
 }));
42. JavaBeanProxy
43. JavaBeanProxy 需求点：设置过的值才提交（UpdateConfig）
44. 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？
45. JavaBeanProxy
46. JavaBeanProxy JSON.toJSONString(object, new PropertyFilter() {
 @Override
 public boolean apply(Object o, String s, Object o1) {
 return JavaBeanProxy.has(o, s);
 }
 });
47. JavaBeanStorage
48. JavaBeanStorage 需求点：设置落地
49. JavaBeanStorage 需求点：设置落地 问题：怎么避免写⼀一堆重复代码？
50. 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());
 }
51. 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());
 }
52. JavaBeanStorage
53. JavaBeanStorage
54. Proxy 还能做什什么？