ARouter的几个常用功能：
1.组件间的页面跳转。
2.依赖注入
3.拦截器。
ARouter-compiler: 这个模块主要用于解析注解，然后生成路由业务代码的java文件，主要需要阅读的源码文件是
RouterProcessor
InterceptorProcessor
AutowiredProcessor
ARouter-api:这个模块主要暴露一些接口和方法给业务层调用，还封装了一个线程池和一些异常等等，建议需要阅读的源码文件
thread包下的文件，理解为什么需要用到线程池
launcher包下的文件，理解初始化过程中做了哪些工作
Warehouse
LogisticsCenter
InterceptorServiceImpl
ARouter-annotation:定义了一些注解。
// 页面跳转
ARouter.getInstance().build("/test/activity").navigation();/**
* Build postcard by path and group
*/
protected Postcard build(String path, String group, Boolean afterReplace) {
if (TextUtils.isEmpty(path) || TextUtils.isEmpty(group)) {
throw new HandlerException(Consts.TAG + "Parameter is invalid!");
} else {
if (!afterReplace) {
PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);
if (null != pService) {
path = pService.forString(path);
}
}
return new Postcard(path, group);
}
}/**
* Use router navigation.
*
* @param context Activity or null.
* @param postcard Route metas
* @param requestCode RequestCode
* @param callback cb
*/
protected Object navigation(final Context context, final Postcard postcard, final int requestCode, final NavigationCallback callback) {
PretreatmentService pretreatmentService = ARouter.getInstance().navigation(PretreatmentService.class);
if (null != pretreatmentService && !pretreatmentService.onPretreatment(context, postcard)) {
// Pretreatment failed, navigation canceled.
return null;
}
// Set context to postcard.
postcard.setContext(null == context ? mContext : context);
try {
LogisticsCenter.completion(postcard);
} catch (NoRouteFoundException ex) {
logger.warning(Consts.TAG, ex.getMessage());
if (debuggable()) {
// Show friendly tips for user.
runInMainThread(new Runnable() {
@Override
public void run() {
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);
} 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;
}
if (null != callback) {
callback.onFound(postcard);
}
if (!postcard.isGreenChannel()) { // It must be run in async thread, maybe interceptor cost too mush time made ANR.
interceptorService.doInterceptions(postcard, new InterceptorCallback() {
/**
* Continue process
*
* @param postcard route meta
*/
@Override
public void onContinue(Postcard postcard) {
_navigation(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(postcard, requestCode, callback);
}
return null;
}build方法传入path和group(可不传)，最后new一个postcard对象，Postcard对象 可以理解为一个封装了页面跳转所需要的内容，它包含页面跳转的参数，动画，context等信息。
在navigation方法里面实现页面跳转的代码是
LogisticsCenter.completion(postcard);然后继续跟
/**
* Completion the postcard by route metas
*
* @param postcard Incomplete postcard, should complete by this method.
*/
public synchronized static void completion(Postcard postcard) {
if (null == postcard) {
throw new NoRouteFoundException(TAG + "No postcard!");
}
RouteMeta routeMeta = Warehouse.routes.get(postcard.getPath());
if (null == routeMeta) {
// Maybe its does't exist, or didn't load.
if (!Warehouse.groupsIndex.containsKey(postcard.getGroup())) {
throw new NoRouteFoundException(TAG + "There is no route match the path [" + postcard.getPath() + "], in group [" + postcard.getGroup() + "]");
} else {
// Load route and cache it into memory, then delete from metas.
try {
if (ARouter.debuggable()) {
logger.debug(TAG, String.format(Locale.getDefault(), "The group [%s] starts loading, trigger by [%s]", postcard.getGroup(), postcard.getPath()));
}
addRouteGroupDynamic(postcard.getGroup(), null);
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); // Reload
}
} else {
postcard.setDestination(routeMeta.getDestination());
postcard.setType(routeMeta.getType());
postcard.setPriority(routeMeta.getPriority());
postcard.setExtra(routeMeta.getExtra());
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) {
logger.error(TAG, "Init provider failed!", e);
throw new HandlerException("Init provider failed!");
}
}
postcard.setProvider(instance);
postcard.greenChannel(); // Provider should skip all of interceptors
break;
case FRAGMENT:
postcard.greenChannel(); // Fragment needn't interceptors
default:
break;
}
}
}我们看到代码会从Warehouse类里面获取RouteMeta对象，如果为null，表示根据路由名找不到路由的目标页面，这个时候，做了一次对group的判断处理.
group是干嘛的？可以理解成分组的意思，因为各个组件交给各个人维护，所以很容易出现路由同名的情况，比如个人中心组件定义了相册选择页面的路由地址，购物车组件也有相册选择页面的路由地址，所以group的存在是为了做细分。
除了细分的作用以外，还可以减少内存的消耗，Warehouse.routes是一个static的map对象，如果一次性把所有路由信息全存放里面，有可能造成内存溢出。所以Group的第二个作用就是按组加载路由表。
根据group的特性不难理解为什么这里有个递归方法
completion(postcard); // Reload不知道有没有人跟我一样疑问，这里不会死循环吗？
public synchronized static void addRouteGroupDynamic(String groupName, IRouteGroup group) throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
if (Warehouse.groupsIndex.containsKey(groupName)){
// If this group is included, but it has not been loaded
// load this group first, because dynamic route has high priority.
Warehouse.groupsIndex.get(groupName).getConstructor().newInstance().loadInto(Warehouse.routes);
Warehouse.groupsIndex.remove(groupName);
}
// cover old group.
if (null != group) {
group.loadInto(Warehouse.routes);
}
}答案是不会，因为当某个group的路由表信息加载到内存的时候，这个group会从groupsIndex里面删除。
如果RouteMeta不为null，解析uri的相关参数，结合RouteMeta的路由信息设置Postcard的参数。然后调用
_navigation(postcard, requestCode, callback);private Object _navigation(final Postcard postcard, final int requestCode, final NavigationCallback callback) {
final Context currentContext = postcard.getContext();
switch (postcard.getType()) {
case ACTIVITY:
// Build intent
final Intent intent = new Intent(currentContext, postcard.getDestination());
intent.putExtras(postcard.getExtras());
// Set flags.
int flags = postcard.getFlags();
if (0 != flags) {
intent.setFlags(flags);
}
// Non activity, need FLAG_ACTIVITY_NEW_TASK
if (!(currentContext instanceof Activity)) {
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
}
// Set Actions
String action = postcard.getAction();
if (!TextUtils.isEmpty(action)) {
intent.setAction(action);
}
// Navigation in main looper.
runInMainThread(new Runnable() {
@Override
public void run() {
startActivity(requestCode, currentContext, intent, postcard, callback);
}
});
break;
case PROVIDER:
return postcard.getProvider();
case BOARDCAST:
case CONTENT_PROVIDER:
case FRAGMENT:
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;
}最后在上面这个方法里面调用了startActvity方法实现跳转。
整个跳转过程中，离不开路由表，接下来分析下路由表的构建流程，即Warehouse类的初始化工作。拦截器的和provider的相关代码先忽略。
class Warehouse {
// Cache route and metas
static Map<String, Class<? extends IRouteGroup>> groupsIndex = new HashMap<>();
static Map<String, RouteMeta> routes = new HashMap<>();
}路由表的构建在初始化阶段。_ARouter的init方法会调用LogisticsCenter.init(mContext, executor);方法
public synchronized static void init(Context context, ThreadPoolExecutor tpe) throws HandlerException {
mContext = context;
executor = tpe;
try {
long startInit = System.currentTimeMillis();
//load by plugin first
loadRouterMap();
if (registerByPlugin) {
logger.info(TAG, "Load router map by arouter-auto-register plugin.");
} else {
Set<String> routerMap;
// It will rebuild router map every times when debuggable.
if (ARouter.debuggable() || PackageUtils.isNewVersion(context)) {
logger.info(TAG, "Run with debug mode or new install, rebuild router map.");
// These class was generated by arouter-compiler.
routerMap = ClassUtils.getFileNameByPackageName(mContext, ROUTE_ROOT_PAKCAGE);
if (!routerMap.isEmpty()) {
context.getSharedPreferences(AROUTER_SP_CACHE_KEY, Context.MODE_PRIVATE).edit().putStringSet(AROUTER_SP_KEY_MAP, routerMap).apply();
}
PackageUtils.updateVersion(context); // Save new version name when router map update finishes.
} else {
logger.info(TAG, "Load router map from cache.");
routerMap = new HashSet<>(context.getSharedPreferences(AROUTER_SP_CACHE_KEY, Context.MODE_PRIVATE).getStringSet(AROUTER_SP_KEY_MAP, new HashSet<String>()));
}
logger.info(TAG, "Find router map finished, map size = " + routerMap.size() + ", cost " + (System.currentTimeMillis() - startInit) + " ms.");
startInit = System.currentTimeMillis();
for (String className : routerMap) {
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)) {
// Load interceptorMeta
((IInterceptorGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.interceptorsIndex);
} else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_PROVIDERS)) {
// Load providerIndex
((IProviderGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.providersIndex);
}
}
}
logger.info(TAG, "Load root element finished, cost " + (System.currentTimeMillis() - startInit) + " ms.");
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() + "]");
}
}我们看到初始化阶段，如果verson非新版本，那么会遍历所有dex文件，找出dex文件里面的ROUTE_ROOT_PAKCAGE = "com.alibaba.android.arouter.routes"的class。
如果已经是新版本了，就从shareprefrence里面读取了缓存，然后根据反射去创建了Class对象，然后将创建好的Group表放到内存中。
这时候又出现新的问题com.alibaba.android.arouter.routes是什么?
从上面的分析，我们知道所有group的class文件都在该package下里面，group的class文件都需要实现IRouteGroup的接口，当我们去看哪些class实现了这些接口的时候，发现都在build目录下。如下图所示。
显而易见，这个class是在编译阶段自动生成的，所以ARouter框架使用了AOP的编程模式。
我们接下来去compiler模块里面看下RouterProcessor类。
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
if (CollectionUtils.isNotEmpty(annotations)) {
Set<? extends Element> routeElements = roundEnv.getElementsAnnotatedWith(Route.class);
try {
logger.info(">>> Found routes, start... <<<");
this.parseRoutes(routeElements);
} catch (Exception e) {
logger.error(e);
}
return true;
}
return false;
}先找到Route注解的Elements，然后解析。
解析的代码比较多，这里分批贴代码分析
// Follow a sequence, find out metas of group first, generate java file, then statistics them as root.
for (Element element : routeElements) {
TypeMirror tm = element.asType();
Route route = element.getAnnotation(Route.class);
RouteMeta routeMeta;
// Activity or Fragment
if (types.isSubtype(tm, type_Activity) || types.isSubtype(tm, fragmentTm) || types.isSubtype(tm, fragmentTmV4)) {
// Get all fields annotation by @Autowired
Map<String, Integer> paramsType = new HashMap<>();
Map<String, Autowired> injectConfig = new HashMap<>();
injectParamCollector(element, paramsType, injectConfig);
if (types.isSubtype(tm, type_Activity)) {
// Activity
logger.info(">>> Found activity route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.ACTIVITY, paramsType);
} else {
// Fragment
logger.info(">>> Found fragment route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.parse(FRAGMENT), paramsType);
}
routeMeta.setInjectConfig(injectConfig);
} else if (types.isSubtype(tm, iProvider)) { // IProvider
logger.info(">>> Found provider route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.PROVIDER, null);
} else if (types.isSubtype(tm, type_Service)) { // Service
logger.info(">>> Found service route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.parse(SERVICE), null);
} else {
throw new RuntimeException("The @Route is marked on unsupported class, look at [" + tm.toString() + "].");
}
categories(routeMeta);
}这里遍历了整个Elements，然后生成对应的RouteMeta。
最后的categories(routeMeta);会对生成的routeMeta做检验，只有合法的routeMeta才会被存入GroupMap里面。path不能为空且path必须是"/"开头才算合法。
然后是通过代码生成java文件，具体生成规则在下面的代码，关键部分补充了注释了。
/** 遍历groupMap **/
for (Map.Entry<String, Set<RouteMeta>> entry : groupMap.entrySet()) {
String groupName = entry.getKey();
/** 创建void loadInto(Map<String, RouteMeta> atlas);方法对象 **/
MethodSpec.Builder loadIntoMethodOfGroupBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
.addAnnotation(Override.class) //注解
.addModifiers(PUBLIC) //方法访问属性
.addParameter(groupParamSpec); //方法参数
List<RouteDoc> routeDocList = new ArrayList<>();
// Build group method body
Set<RouteMeta> groupData = entry.getValue();
/** 遍历每个groupMap下的routeMeta **/
for (RouteMeta routeMeta : groupData) {
RouteDoc routeDoc = extractDocInfo(routeMeta);
ClassName className = ClassName.get((TypeElement) routeMeta.getRawType());
switch (routeMeta.getType()) {
case PROVIDER: // Need cache provider's super class
List<? extends TypeMirror> interfaces = ((TypeElement) routeMeta.getRawType()).getInterfaces();
for (TypeMirror tm : interfaces) {
routeDoc.addPrototype(tm.toString());
if (types.isSameType(tm, iProvider)) { // Its implements iProvider interface himself.
// This interface extend the IProvider, so it can be used for mark provider
loadIntoMethodOfProviderBuilder.addStatement(
"providers.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, null, " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
(routeMeta.getRawType()).toString(),
routeMetaCn,
routeTypeCn,
className,
routeMeta.getPath(),
routeMeta.getGroup());
} else if (types.isSubtype(tm, iProvider)) {
// This interface extend the IProvider, so it can be used for mark provider
loadIntoMethodOfProviderBuilder.addStatement(
"providers.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, null, " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
tm.toString(), // So stupid, will duplicate only save class name.
routeMetaCn,
routeTypeCn,
className,
routeMeta.getPath(),
routeMeta.getGroup());
}
}
break;
default:
break;
}
// Make map body for paramsType
StringBuilder mapBodyBuilder = new StringBuilder();
Map<String, Integer> paramsType = routeMeta.getParamsType();
Map<String, Autowired> injectConfigs = routeMeta.getInjectConfig();
if (MapUtils.isNotEmpty(paramsType)) {
List<RouteDoc.Param> paramList = new ArrayList<>();
for (Map.Entry<String, Integer> types : paramsType.entrySet()) {
mapBodyBuilder.append("put(\"").append(types.getKey()).append("\", ").append(types.getValue()).append("); ");
RouteDoc.Param param = new RouteDoc.Param();
Autowired injectConfig = injectConfigs.get(types.getKey());
param.setKey(types.getKey());
param.setType(TypeKind.values()[types.getValue()].name().toLowerCase());
param.setDescription(injectConfig.desc());
param.setRequired(injectConfig.required());
paramList.add(param);
}
routeDoc.setParams(paramList);
}
String mapBody = mapBodyBuilder.toString();
/**
* loadInto方法里面加入具体的代码实现
* 比如atlas.put("/module/2", RouteMeta.build(RouteType.ACTIVITY, TestModule2Activity.class, "/module/2", "m2", null, -1, -2147483648));
* **/
loadIntoMethodOfGroupBuilder.addStatement(
"atlas.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, " + (StringUtils.isEmpty(mapBody) ? null : ("new java.util.HashMap<String, Integer>(){{" + mapBodyBuilder.toString() + "}}")) + ", " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
routeMeta.getPath(),
routeMetaCn,
routeTypeCn,
className,
routeMeta.getPath().toLowerCase(),
routeMeta.getGroup().toLowerCase());
routeDoc.setClassName(className.toString());
routeDocList.add(routeDoc);
}
// Generate groups
/**生成java文件**/
String groupFileName = NAME_OF_GROUP + groupName;
JavaFile.builder(PACKAGE_OF_GENERATE_FILE, //指定java文件的包路径
TypeSpec.classBuilder(groupFileName) //java文件名
.addJavadoc(WARNING_TIPS) //java注解
.addSuperinterface(ClassName.get(type_IRouteGroup)) //继承的接口
.addModifiers(PUBLIC) //类属性 公有
.addMethod(loadIntoMethodOfGroupBuilder.build()) //加入方法
.build()
).build().writeTo(mFiler);
logger.info(">>> Generated group: " + groupName + "<<<");
rootMap.put(groupName, groupFileName); //将组名和java文件名做映射关系
docSource.put(groupName, routeDocList);
}最后在生成root的java文件。
// Write root meta into disk.
String rootFileName = NAME_OF_ROOT + SEPARATOR + moduleName;
JavaFile.builder(PACKAGE_OF_GENERATE_FILE,
TypeSpec.classBuilder(rootFileName)
.addJavadoc(WARNING_TIPS)
.addSuperinterface(ClassName.get(elementUtils.getTypeElement(ITROUTE_ROOT)))
.addModifiers(PUBLIC)
.addMethod(loadIntoMethodOfRootBuilder.build())
.build()
).build().writeTo(mFiler);AOP阶段路由表的生成规则总结:
1.解析注解得到带有Route注解相关的Elements。
2.遍历所有Elements并解析Route注解的参数，生成对应的RouteMeta数据 ，并插入到groupMap中
3.遍历groupMap，将每个groupName下的所有的RouteMeta生成对应的java代码，然后写入该java文件到内存。此时一个groupName对应一个java文件。
4.并将每个groupName和生成的java文件做映射放在rootMap中。
5.最后再生成对应的root的java文件，该文件主要用于初始化的时候将groupName和java文件的映射关系加载进内存。
到这里，整个页面路由的逻辑都已经理清楚了。
AutowiredProcessor类和Autowired注解
@Override
public boolean process(Set<? extends TypeElement> set, RoundEnvironment roundEnvironment) {
if (CollectionUtils.isNotEmpty(set)) {
try {
logger.info(">>> Found autowired field, start... <<<");
categories(roundEnvironment.getElementsAnnotatedWith(Autowired.class));
generateHelper();
} catch (Exception e) {
logger.error(e);
}
return true;
}
return false;
}private void categories(Set<? extends Element> elements) throws IllegalAccessException {
if (CollectionUtils.isNotEmpty(elements)) {
for (Element element : elements) {
TypeElement enclosingElement = (TypeElement) element.getEnclosingElement();
if (element.getModifiers().contains(Modifier.PRIVATE)) {
throw new IllegalAccessException("The inject fields CAN NOT BE 'private'!!! please check field ["
+ element.getSimpleName() + "] in class [" + enclosingElement.getQualifiedName() + "]");
}
if (parentAndChild.containsKey(enclosingElement)) { // Has categries
parentAndChild.get(enclosingElement).add(element);
} else {
List<Element> childs = new ArrayList<>();
childs.add(element);
parentAndChild.put(enclosingElement, childs);
}
}
logger.info("categories finished.");
}
}编译阶段会去解析Autowired注解，然后获取带有该注解的Elements，然后遍历，如果是私有属性，直接抛异常。然后将正确的elements存到parentAndChild map里面。
接着开始根据parentAndChild的数据里面的内容生成对应的java文件。
生成autowired的java文件步骤和生成ARouter的步骤相似；
1.创建inject方法对象。inject方法在ISyringe接口里面定义了，所以所有autowired类实现该接口。
2.先判断是否是provder，不是provider，然后去区分是activity还是fragment，activity情况下通过getintent去取参数，fragment情况下通过getArguments方法去取参数。
3.然后根据element属性生成对应的get代码，比如boolean对应getBooleanExtra()方法。
4.判断autowired注解里面的required是否是true，如果是true并且是非基本数据类型，则加入对象是否为null的判断代码。
5.此时autowired注解相关的java文件已经生成完毕。
当我们在某个地方调用如下方法的时候：依赖注入才开始生效。
ARouter.getInstance().inject(this);然后跟下这个方法，会走到这里
static void inject(Object thiz) {
AutowiredService autowiredService = ((AutowiredService) ARouter.getInstance().build("/arouter/service/autowired").navigation());
if (null != autowiredService) {
autowiredService.autowire(thiz);
}
}这里用到一个AutowiredService，这个接口继承了IProvider的接口。然后在AutowiredServiceImpl类里面找到了该接口的具体实现。这个实现类也加了Router注解，那么这里有个新的问题，IProvider是干嘛的？
这里我们要回到RouteProcessor看下Provider的解析代码：
switch (routeMeta.getType()) {
case PROVIDER: // Need cache provider's super class
List<? extends TypeMirror> interfaces = ((TypeElement) routeMeta.getRawType()).getInterfaces();
for (TypeMirror tm : interfaces) {
routeDoc.addPrototype(tm.toString());
if (types.isSameType(tm, iProvider)) { // Its implements iProvider interface himself.
// This interface extend the IProvider, so it can be used for mark provider
loadIntoMethodOfProviderBuilder.addStatement(
"providers.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, null, " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
(routeMeta.getRawType()).toString(),
routeMetaCn,
routeTypeCn,
className,
routeMeta.getPath(),
routeMeta.getGroup());
} else if (types.isSubtype(tm, iProvider)) {
// This interface extend the IProvider, so it can be used for mark provider
loadIntoMethodOfProviderBuilder.addStatement(
"providers.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, null, " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
tm.toString(), // So stupid, will duplicate only save class name.
routeMetaCn,
routeTypeCn,
className,
routeMeta.getPath(),
routeMeta.getGroup());
}
}
break;
default:
break;
}这里看到如果是provider，会生成一段代码，这段代码会将定义的Interface和该interface的实现类做映射，前提条件是，该interface必须继承IProvider。
那做映射干嘛呢？
我们再去看下Provider的映射表使用的地方。也是在wareHouse类里面，发现和路由跳转一样，也是build()方法里面传入string，然后navigation跳转，其实到这里已经能猜到要干嘛了，为了实现跨组件间的方法调用嘛，比如组件A调用组件B里面的Class C的方法，那么就定义一个interface，然后interface下沉到底层组件，Class C继承该interface并实现该方法，接着按照ARouter的provder配置好后，就能在组件A中调用组件B的Class C的暴露的接口了，组件A也不需要去依赖组件B。
这样做得好处就是减少组件间依赖关系。
Provider已经理解了，我们继续AutowiredService分析。
/**
* Recursive injection
*
* @param instance who call me.
* @param parent parent of me.
*/
private void doInject(Object instance, Class<?> parent) {
Class<?> clazz = null == parent ? instance.getClass() : parent;
ISyringe syringe = getSyringe(clazz);
if (null != syringe) {
syringe.inject(instance);
}
Class<?> superClazz = clazz.getSuperclass();
// has parent and its not the class of framework.
if (null != superClazz && !superClazz.getName().startsWith("android")) {
doInject(instance, superClazz);
}
}
private ISyringe getSyringe(Class<?> clazz) {
String className = clazz.getName();
try {
if (!blackList.contains(className)) {
ISyringe syringeHelper = classCache.get(className);
if (null == syringeHelper) { // No cache.
syringeHelper = (ISyringe) Class.forName(clazz.getName() + SUFFIX_AUTOWIRED).getConstructor().newInstance();
}
classCache.put(className, syringeHelper);
return syringeHelper;
}
} catch (Exception e) {
blackList.add(className); // This instance need not autowired.
}
return null;
}这段代码也好理解，获取传入object对象的class对象，通过类名找到编译阶段生成的实现ISyring接口的相关类，反射创建对象，然后调用该对象的inject方法。
至此:依赖注入也分析完了。
拦截器是什么，参考OKHttp的实现，拦截器就是在处理一个任务的时候，在该任务之前或者之后加入自己的业务逻辑。拦截器设计模式可以有效减少耦合度。
IntercepterProcessor的注解解析其实和前面两个差不多，拦截器表也在Warehouse类里维护。
区别是拦截器提供了手动注册的方法，不一定要通过Aop的方式去注册。
if (!postcard.isGreenChannel()) { // It must be run in async thread, maybe interceptor cost too mush time made ANR.
interceptorService.doInterceptions(postcard, new InterceptorCallback() {
/**
* Continue process
*
* @param postcard route meta
*/
@Override
public void onContinue(Postcard postcard) {
_navigation(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(postcard, requestCode, callback);
}这里我们看到如果是绿色通道，则会调用拦截器的方法。
那什么时候是绿色通道呢？
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) {
logger.error(TAG, "Init provider failed!", e);
throw new HandlerException("Init provider failed!");
}
}
postcard.setProvider(instance);
postcard.greenChannel(); // Provider should skip all of interceptors
break;
case FRAGMENT:
postcard.greenChannel(); // Fragment needn't interceptors
default:
break;
}这里我们看到如果是fragment或者provider的时候，打开了绿色通道，所以这两个不会经过拦截器。
然后我们到InterceptorServiceImpl看下拦截器的执行过程
@Override
public void doInterceptions(final Postcard postcard, final InterceptorCallback callback) {
if (MapUtils.isNotEmpty(Warehouse.interceptorsIndex)) {
checkInterceptorsInitStatus();
if (!interceptorHasInit) {
callback.onInterrupt(new HandlerException("Interceptors initialization takes too much time."));
return;
}
LogisticsCenter.executor.execute(new Runnable() {
@Override
public void run() {
CancelableCountDownLatch interceptorCounter = new CancelableCountDownLatch(Warehouse.interceptors.size());
try {
_execute(0, interceptorCounter, postcard);
interceptorCounter.await(postcard.getTimeout(), TimeUnit.SECONDS);
if (interceptorCounter.getCount() > 0) { // Cancel the navigation this time, if it hasn't return anythings.
callback.onInterrupt(new HandlerException("The interceptor processing timed out."));
} else if (null != postcard.getTag()) { // Maybe some exception in the tag.
callback.onInterrupt((Throwable) postcard.getTag());
} else {
callback.onContinue(postcard);
}
} catch (Exception e) {
callback.onInterrupt(e);
}
}
});
} else {
callback.onContinue(postcard);
}
}1.校验拦截器是否初始化。
2.开启线程执行拦截器内部代码。
private static void _execute(final int index, final CancelableCountDownLatch counter, final Postcard postcard) {
if (index < Warehouse.interceptors.size()) {
IInterceptor iInterceptor = Warehouse.interceptors.get(index);
iInterceptor.process(postcard, new InterceptorCallback() {
@Override
public void onContinue(Postcard postcard) {
// Last interceptor excute over with no exception.
counter.countDown();
_execute(index + 1, counter, postcard); // When counter is down, it will be execute continue ,but index bigger than interceptors size, then U know.
}
@Override
public void onInterrupt(Throwable exception) {
// Last interceptor execute over with fatal exception.
postcard.setTag(null == exception ? new HandlerException("No message.") : exception); // save the exception message for backup.
counter.cancel();
// Be attention, maybe the thread in callback has been changed,
// then the catch block(L207) will be invalid.
// The worst is the thread changed to main thread, then the app will be crash, if you throw this exception!
// if (!Looper.getMainLooper().equals(Looper.myLooper())) { // You shouldn't throw the exception if the thread is main thread.
// throw new HandlerException(exception.getMessage());
// }
}
});
}
}按照从0--n的顺序执行拦截器。
这里拦截器的代码也分析完了。