Android路由框架ARouter分析

String path();//路径URL字符串
String group() default "";//组名，默认为一级路径名；一旦被设置，跳转时必须赋值
String name() default "undefined";//该路径的名称，用于产生JavaDoc
int extras() default Integer.MIN_VALUE;//额外配置的开关信息；譬如某些页面是否需要网络校验、登录校验等
int priority() default -1;//该路径的优先级

BlankFragment @Route(path = "/test/fragment") 
Test1Activity @Route(path = "/test/activity1")

boolean required() default false;
String desc() default "No desc.";

@Autowired
int age = 10;
@Autowired
HelloService helloService;

int priority();//该拦截器的优先级
String name() default "Default";//该拦截器的名称，用于产生JavaDoc

@Interceptor(priority = 7)
public class Test1Interceptor implements IInterceptor {
 @Override
 public void process(final Postcard postcard, final InterceptorCallback callback) {
 ............
 }
}

public class ARouter$$Root$$app implements IRouteRoot {
 @Override
 public void loadInto(Map<String, Class<? extends IRouteGroup>> routes) {
 routes.put("service", ARouter$$Group$$service.class);
 routes.put("test", ARouter$$Group$$test.class);
 }
}

public static void init(Application application) {//静态函数进行初始化，不依赖对象
 if (!hasInit) {
  logger = _ARouter.logger; //持有 日志打印的 全局静态标量
  _ARouter.logger.info(Consts.TAG, "ARouter init start.");//打印 ARouter初始化日志
  hasInit = _ARouter.init(application);//移交 _ARouter去 初始化

  if (hasInit) {
   _ARouter.afterInit();
  }

  _ARouter.logger.info(Consts.TAG, "ARouter init over.");//打印 ARouter初始化日志
 }
}

protected static synchronized boolean init(Application application) {
  mContext = application;// Application的上下文
  LogisticsCenter.init(mContext, executor);//移交逻辑中心进行初始化，并传入线城池对象
  logger.info(Consts.TAG, "ARouter init success!");//打印日志
  hasInit = true;//标示是否初始化完成

  // It's not a good idea.
  // if (Build.VERSION.SDK_INT > Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
  //  application.registerActivityLifecycleCallbacks(new AutowiredLifecycleCallback());
  // }
  return true;
 }

public synchronized static void init(Context context, ThreadPoolExecutor tpe) throws HandlerException {
  mContext = context; //静态持有Application的上下文
  executor = tpe;//静态持有 线城池

  try {
   // These class was generate by arouter-compiler.
   // 通过指定包名com.alibaba.android.arouter.routes，找到所有 编译期产生的routes目录下的类名(不包含装载类)
   List<String> classFileNames = ClassUtils.getFileNameByPackageName(mContext, ROUTE_ROOT_PAKCAGE);

   for (String className : classFileNames) {//组别列表com.alibaba.android.arouter.routes.ARouter\$\$Root
    if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_ROOT)) {
     // This one of root elements, load root.
     ((IRouteRoot) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.groupsIndex);
    } else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_INTERCEPTORS)) {//模块内的拦截器列表com.alibaba.android.arouter.routes.ARouter\$\$Interceptors
     // Load interceptorMeta
     ((IInterceptorGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.interceptorsIndex);
    } else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_PROVIDERS)) {//IOC的动作路由列表com.alibaba.android.arouter.routes.ARouter\$\$Providers
     // Load providerIndex
     ((IProviderGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.providersIndex);
    }
   }

   if (Warehouse.groupsIndex.size() == 0) {
    logger.error(TAG, "No mapping files were found, check your configuration please!");
   }

   if (ARouter.debuggable()) {
    logger.debug(TAG, String.format(Locale.getDefault(), "LogisticsCenter has already been loaded, GroupIndex[%d], InterceptorIndex[%d], ProviderIndex[%d]", Warehouse.groupsIndex.size(), Warehouse.interceptorsIndex.size(), Warehouse.providersIndex.size()));
   }
  } catch (Exception e) {
   throw new HandlerException(TAG + "ARouter init logistics center exception! [" + e.getMessage() + "]");
  }
 }

class Warehouse {
 // Cache route and metas
 static Map<String, Class<? extends IRouteGroup>> groupsIndex = new HashMap<>();//组别的列表 包含了组名与对应组内的路由清单列表Class的映射关系
 static Map<String, RouteMeta> routes = new HashMap<>();//组内的路由列表 包含了对应分组下的，路由URL与目标对象Class的映射关系

 // Cache provider
 static Map<Class, IProvider> providers = new HashMap<>(); //缓存IOC 目标class与已经创建了的对象 
 
 static Map<String, RouteMeta> providersIndex = new HashMap<>();//IOC 的动作路由列表包含了使用依赖注入方式的某class的 路由URL 与class映射关系

 // Cache interceptor
 //模块内的拦截器列表 包含了某个模块下的拦截器 与 优先级的映射关系
 static Map<Integer, Class<? extends IInterceptor>> interceptorsIndex = new UniqueKeyTreeMap<>("More than one interceptors use same priority [%s]");
 static List<IInterceptor> interceptors = new ArrayList<>();//已排序的拦截器实例对象
 
}

ARouter.getInstance().build("/test/activity2").navigation();</pre>

public Postcard build(String path) {
 return _ARouter.getInstance().build(path);
}

protected Postcard build(String path) {
  if (TextUtils.isEmpty(path)) {
   throw new HandlerException(Consts.TAG + "Parameter is invalid!");
  } else {
   PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);
   if (null != pService) {
    path = pService.forString(path);
   }
   return build(path, extractGroup(path));
  }
 }

public interface PathReplaceService extends IProvider {

 /**
  * For normal path.
  *
  * @param path raw path
  */
 String forString(String path);

 /**
  * For uri type.
  *
  * @param uri raw uri
  */
 Uri forUri(Uri uri);
}

protected <T> T navigation(Class<? extends T> service) {
 try {
  Postcard postcard = LogisticsCenter.buildProvider(service.getName());

  // Compatible 1.0.5 compiler sdk.
  if (null == postcard) { // No service, or this service in old version.
   postcard = LogisticsCenter.buildProvider(service.getSimpleName());
  }

  LogisticsCenter.completion(postcard);
  return (T) postcard.getProvider();
 } catch (NoRouteFoundException ex) {
  logger.warning(Consts.TAG, ex.getMessage());
  return null;
 }
}

public Object navigation() {
  return navigation(null);
 }
 
 public Object navigation(Context context) {
  return navigation(context, null);
 }

 public Object navigation(Context context, NavigationCallback callback) {
  return ARouter.getInstance().navigation(context, this, -1, callback);
 }

 public void navigation(Activity mContext, int requestCode) {
  navigation(mContext, requestCode, null);
 }

 public void navigation(Activity mContext, int requestCode, NavigationCallback callback) {
  ARouter.getInstance().navigation(mContext, this, requestCode, callback);
 }

protected Object navigation(final Context context, final Postcard postcard, final int requestCode, final NavigationCallback callback) {
  try {
   LogisticsCenter.completion(postcard);
  } catch (NoRouteFoundException ex) {
   logger.warning(Consts.TAG, ex.getMessage());

   if (debuggable()) { // Show friendly tips for user.
    Toast.makeText(mContext, "There's no route matched!\n" +
      " Path = [" + postcard.getPath() + "]\n" +
      " Group = [" + postcard.getGroup() + "]", Toast.LENGTH_LONG).show();
   }
 
   if (null != callback) {
    callback.onLost(postcard);//触发路由查找失败
   } else { // No callback for this invoke, then we use the global degrade service.
    DegradeService degradeService = ARouter.getInstance().navigation(DegradeService.class);
    if (null != degradeService) {
     degradeService.onLost(context, postcard);
    }
   }

   return null;
  }
  //找到了路由元信息，触发路由查找的回调
  if (null != callback) {
   callback.onFound(postcard);
  }
  //绿色通道校验 需要拦截处理
  if (!postcard.isGreenChannel()) { // It must be run in async thread, maybe interceptor cost too mush time made ANR.
   //调用拦截器截面控制器，遍历内存仓库的自定义拦截器，并在异步线程中执行拦截函数
   interceptorService.doInterceptions(postcard, new InterceptorCallback() {
    /**
     * Continue process
     *
     * @param postcard route meta
     */
    @Override
    public void onContinue(Postcard postcard) {
     _navigation(context, postcard, requestCode, callback);
    }

    /**
     * Interrupt process, pipeline will be destory when this method called.
     *
     * @param exception Reson of interrupt.
     */
    @Override
    public void onInterrupt(Throwable exception) {
     if (null != callback) {
      callback.onInterrupt(postcard);
     }

     logger.info(Consts.TAG, "Navigation failed, termination by interceptor : " + exception.getMessage());
    }
   });
  } else {
   return _navigation(context, postcard, requestCode, callback);
  }

  return null;
 }

public synchronized static void completion(Postcard postcard) {
 if (null == postcard) {
  throw new NoRouteFoundException(TAG + "No postcard!");
 }
 //根据路径URL获取到路径元信息
 RouteMeta routeMeta = Warehouse.routes.get(postcard.getPath());
 if (null == routeMeta) { // Maybe its does't exist, or didn't load.
  //可能没加载组内清单路径，从组别的清单列表拿到对应组
  Class<? extends IRouteGroup> groupMeta = Warehouse.groupsIndex.get(postcard.getGroup()); // Load route meta.
  if (null == groupMeta) {
   throw new NoRouteFoundException(TAG + "There is no route match the path [" + postcard.getPath() + "], in group [" + postcard.getGroup() + "]");
  } else {
   //将该组的组内清单列表加入到内存仓库中，并把组别移除
   try {
    if (ARouter.debuggable()) {
     logger.debug(TAG, String.format(Locale.getDefault(), "The group [%s] starts loading, trigger by [%s]", postcard.getGroup(), postcard.getPath()));
    }

    IRouteGroup iGroupInstance = groupMeta.getConstructor().newInstance();
    iGroupInstance.loadInto(Warehouse.routes);
    Warehouse.groupsIndex.remove(postcard.getGroup());

    if (ARouter.debuggable()) {
     logger.debug(TAG, String.format(Locale.getDefault(), "The group [%s] has already been loaded, trigger by [%s]", postcard.getGroup(), postcard.getPath()));
    }
   } catch (Exception e) {
    throw new HandlerException(TAG + "Fatal exception when loading group meta. [" + e.getMessage() + "]");
   }

   completion(postcard); // 再次触发完善逻辑
  }
 } else {
  postcard.setDestination(routeMeta.getDestination());//目标 class
  postcard.setType(routeMeta.getType());//路由类
  postcard.setPriority(routeMeta.getPriority());//路由优先级
  postcard.setExtra(routeMeta.getExtra());//额外的配置开关信息

  Uri rawUri = postcard.getUri();
  if (null != rawUri) { // Try to set params into bundle.
   Map<String, String> resultMap = TextUtils.splitQueryParameters(rawUri);
   Map<String, Integer> paramsType = routeMeta.getParamsType();

   if (MapUtils.isNotEmpty(paramsType)) {
    // Set value by its type, just for params which annotation by @Param
    for (Map.Entry<String, Integer> params : paramsType.entrySet()) {
     setValue(postcard,
       params.getValue(),
       params.getKey(),
       resultMap.get(params.getKey()));
    }

    // Save params name which need auto inject.
    postcard.getExtras().putStringArray(ARouter.AUTO_INJECT, paramsType.keySet().toArray(new String[]{}));
   }

   // Save raw uri
   postcard.withString(ARouter.RAW_URI, rawUri.toString());
  }

  switch (routeMeta.getType()) {
   case PROVIDER: // if the route is provider, should find its instance
    // Its provider, so it must implement IProvider
    Class<? extends IProvider> providerMeta = (Class<? extends IProvider>) routeMeta.getDestination();
    IProvider instance = Warehouse.providers.get(providerMeta);
    if (null == instance) { // There's no instance of this provider
     IProvider provider;
     try {
      provider = providerMeta.getConstructor().newInstance();
      provider.init(mContext);
      Warehouse.providers.put(providerMeta, provider);
      instance = provider;
     } catch (Exception e) {
      throw new HandlerException("Init provider failed! " + e.getMessage());
     }
    }
    postcard.setProvider(instance);
    postcard.greenChannel(); // Provider should skip all of interceptors
    break;
   case FRAGMENT:
    postcard.greenChannel(); // Fragment needn't interceptors
   default:
    break;
  }
 }
}

private Object _navigation(final Context context, final Postcard postcard, final int requestCode, final NavigationCallback callback) {
  final Context currentContext = null == context ? mContext : context;

  switch (postcard.getType()) {
   case ACTIVITY://如果是Acitvity，则实现Intent跳转
    // Build intent
    final Intent intent = new Intent(currentContext, postcard.getDestination());
    intent.putExtras(postcard.getExtras());

    // Set flags.
    int flags = postcard.getFlags();
    if (-1 != flags) {
     intent.setFlags(flags);
    } else if (!(currentContext instanceof Activity)) { // Non activity, need less one flag.
     intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    }

    // Navigation in main looper.
    new Handler(Looper.getMainLooper()).post(new Runnable() {
     @Override
     public void run() {
      if (requestCode > 0) { // Need start for result
       ActivityCompat.startActivityForResult((Activity) currentContext, intent, requestCode, postcard.getOptionsBundle());
      } else {
       ActivityCompat.startActivity(currentContext, intent, postcard.getOptionsBundle());
      }

      if ((-1 != postcard.getEnterAnim() && -1 != postcard.getExitAnim()) && currentContext instanceof Activity) { // Old version.
       ((Activity) currentContext).overridePendingTransition(postcard.getEnterAnim(), postcard.getExitAnim());
      }

      if (null != callback) { // Navigation over.
       callback.onArrival(postcard);
      }
     }
    });

    break;
   case PROVIDER://如果是IOC，则返回目标对象实例
    return postcard.getProvider();
   case BOARDCAST:
   case CONTENT_PROVIDER:
   case FRAGMENT://如果是Fragment，则返回实例，并填充bundle
    Class fragmentMeta = postcard.getDestination();
    try {
     Object instance = fragmentMeta.getConstructor().newInstance();
     if (instance instanceof Fragment) {
      ((Fragment) instance).setArguments(postcard.getExtras());
     } else if (instance instanceof android.support.v4.app.Fragment) {
      ((android.support.v4.app.Fragment) instance).setArguments(postcard.getExtras());
     }

     return instance;
    } catch (Exception ex) {
     logger.error(Consts.TAG, "Fetch fragment instance error, " + TextUtils.formatStackTrace(ex.getStackTrace()));
    }
   case METHOD:
   case SERVICE:
   default:
    return null;
  }

  return null;
 }