arouter-compiler version : 1.2.2

前言

之前对 arouter-api 做了整个流程的分析，今天来看看 arouter-compiler 。

arouter-compiler 主要是利用 apt 在编译期自动生成代码的。之前我们看到的 ARouter$$Root$$app 、 ARouter$$Group$$test 和 Test1Activity$$ARouter$$Autowired 等都是 arouter-compiler 生成的。

那接下来就分析分析 arouter-compiler 是怎样生成这些源码的。

arouter-compiler

arouter-compiler 中 processor 有三种：

• AutowiredProcessor : 用来生成像 Test1Activity$$ARouter$$Autowired 这种类型；
• InterceptorProcessor : 用来生成像 ARouter$$Interceptors$$app 这种类型；
• RouteProcessor : 用来生成像 ARouter$$Root$$app ，ARouter$$Providers$$app 和 ARouter$$Group$$test 这种类型；

RouteProcessor

在这里我们就只分析 RouteProcessor 了。

RouteProcessor 相比其余两个 Processor 来说，代码更长，逻辑更加复杂。并且 RouteProcessor 主要解决的是路由映射这一块。其余两个 RouteProcessor 也是大同小异，有兴趣的同学可以自行阅读源码。

先来看看 RouteProcessor 的定义：

@AutoService(Processor.class)@SupportedOptions({KEY_MODULE_NAME, KEY_GENERATE_DOC_NAME})@SupportedSourceVersion(SourceVersion.RELEASE_7)@SupportedAnnotationTypes({ANNOTATION_TYPE_ROUTE, ANNOTATION_TYPE_AUTOWIRED})public class RouteProcessor extends AbstractProcessor {    ...}

RouteProcessor 类上面的注解很多，我们一个一个来看：

• @AutoService 会自动在 META-INF 文件夹下生成 Processor 配置信息文件，避免手动配置的麻烦;
• @SupportedOptions 指定 Processor 支持的选项参数名称，KEY_MODULE_NAME 就是 AROUTER_MODULE_NAME ，KEY_GENERATE_DOC_NAME 就是 AROUTER_GENERATE_DOC；没错，这两个就是我们一开始在 build.gradle 中配置的。
• @SupportedSourceVersion 指定 Processor 支持的 JDK 的版本；
• @SupportedAnnotationTypes 指定 Processor 解决的注解；

接着，趁热打铁。来瞧瞧 RouteProcessor 的 init 方法。

@Overridepublic synchronized void init(ProcessingEnvironment processingEnv) {    super.init(processingEnv);    mFiler = processingEnv.getFiler();                  // Generate class.    types = processingEnv.getTypeUtils();            // Get type utils.    elements = processingEnv.getElementUtils();      // Get class meta.    typeUtils = new TypeUtils(types, elements);    logger = new Logger(processingEnv.getMessager());   // Package the log utils.    // Attempt to get user configuration [moduleName]    Map<String, String> options = processingEnv.getOptions();    if (MapUtils.isNotEmpty(options)) {        moduleName = options.get(KEY_MODULE_NAME);        generateDoc = VALUE_ENABLE.equals(options.get(KEY_GENERATE_DOC_NAME));    }    if (StringUtils.isNotEmpty(moduleName)) {        moduleName = moduleName.replaceAll("[^0-9a-zA-Z_]+", "");        logger.info("The user has configuration the module name, it was [" + moduleName + "]");    } else {        logger.error(NO_MODULE_NAME_TIPS);        throw new RuntimeException("ARouter::Compiler >>> No module name, for more information, look at gradle log.");    }    // 假如需要生成路由 doc    if (generateDoc) {        try {            docWriter = mFiler.createResource(                    StandardLocation.SOURCE_OUTPUT,                    PACKAGE_OF_GENERATE_DOCS,                    "arouter-map-of-" + moduleName + ".json"            ).openWriter();        } catch (IOException e) {            logger.error("Create doc writer failed, because " + e.getMessage());        }    }    iProvider = elements.getTypeElement(Consts.IPROVIDER).asType();    logger.info(">>> RouteProcessor init. <<<");}

在 init 方法中，主要获取了 KEY_MODULE_NAME 和 KEY_GENERATE_DOC_NAME 这两个编译选项参数。而后判断一下能否需要生成路由文档。

在 init 方法中获取参数后，接着就是 process 方法。

process 方法就如同是 main 方法一样，在这里面都是 processer 解决注解自动生成代码的逻辑。

@Overridepublic boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {    if (CollectionUtils.isNotEmpty(annotations)) {        // 获取 @Route 注解的集合        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;}

在 process 中调用了 parseRoutes ，parseRoutes 方法实在是太长了，在这里我们进行分段讲解吧。

private void parseRoutes(Set<? extends Element> routeElements) throws IOException {    if (CollectionUtils.isNotEmpty(routeElements)) {        // prepare the type an so on.            logger.info(">>> Found routes, size is " + routeElements.size() + " <<<");            rootMap.clear();        // Activity 类型        TypeMirror type_Activity = elements.getTypeElement(ACTIVITY).asType();        // Service 类型        TypeMirror type_Service = elements.getTypeElement(SERVICE).asType();        // Fragment 类型        TypeMirror fragmentTm = elements.getTypeElement(FRAGMENT).asType();        // v4 Fragment 类型        TypeMirror fragmentTmV4 = elements.getTypeElement(Consts.FRAGMENT_V4).asType();            // IRouteGroup 类型        TypeElement type_IRouteGroup = elements.getTypeElement(IROUTE_GROUP);        // IProviderGroup 类型        TypeElement type_IProviderGroup = elements.getTypeElement(IPROVIDER_GROUP);        // 获取 RouteMeta 和 RouteType 的类名        ClassName routeMetaCn = ClassName.get(RouteMeta.class);        ClassName routeTypeCn = ClassName.get(RouteType.class);            /*           构造 ARouter$$Root$$xxx 的 loadInto 方法入参类型           Build input type, format as :               Map<String, Class<? extends IRouteGroup>>         */        ParameterizedTypeName inputMapTypeOfRoot = ParameterizedTypeName.get(                ClassName.get(Map.class),                ClassName.get(String.class),                ParameterizedTypeName.get(                        ClassName.get(Class.class),                        WildcardTypeName.subtypeOf(ClassName.get(type_IRouteGroup))                )        );            /*          构造 ARouter$$Group$$xxx 的 loadInto 方法入参类型          Map<String, RouteMeta>         */        ParameterizedTypeName inputMapTypeOfGroup = ParameterizedTypeName.get(                ClassName.get(Map.class),                ClassName.get(String.class),                ClassName.get(RouteMeta.class)        );            /*          构造方法入参参数名称          Build input param name.         */        ParameterSpec rootParamSpec = ParameterSpec.builder(inputMapTypeOfRoot, "routes").build();        ParameterSpec groupParamSpec = ParameterSpec.builder(inputMapTypeOfGroup, "atlas").build();        ParameterSpec providerParamSpec = ParameterSpec.builder(inputMapTypeOfGroup, "providers").build();  // Ps. its param type same as groupParamSpec!            /*          构造 ARouter$$Root$$xxx 的 loadInto 方法          Build method : 'loadInto'         */        MethodSpec.Builder loadIntoMethodOfRootBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)                .addAnnotation(Override.class)                .addModifiers(PUBLIC)                .addParameter(rootParamSpec);            ...            }}

parseRoutes 方法一开始，做足了准备。下面就到了放大招的时候了。

//  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;    // 假如 element 修饰的类是 Activity 类型的    if (types.isSubtype(tm, type_Activity)) {                 // Activity        logger.info(">>> Found activity route: " + tm.toString() + " <<<");        // 获取 Activity 中 @Autowired 注解的属性，IProvider 类型的除外        Map<String, Integer> paramsType = new HashMap<>();        Map<String, Autowired> injectConfig = new HashMap<>();        for (Element field : element.getEnclosedElements()) {            if (field.getKind().isField() && field.getAnnotation(Autowired.class) != null && !types.isSubtype(field.asType(), iProvider)) {                // It must be field, then it has annotation, but it not be provider.                Autowired paramConfig = field.getAnnotation(Autowired.class);                String injectName = StringUtils.isEmpty(paramConfig.name()) ? field.getSimpleName().toString() : paramConfig.name();                paramsType.put(injectName, typeUtils.typeExchange(field));                injectConfig.put(injectName, paramConfig);            }        }        // 构造 activity 类型的路由数据        routeMeta = new RouteMeta(route, element, RouteType.ACTIVITY, paramsType);        routeMeta.setInjectConfig(injectConfig);    } else if (types.isSubtype(tm, iProvider)) {         // IProvider 类型        logger.info(">>> Found provider route: " + tm.toString() + " <<<");        routeMeta = new RouteMeta(route, element, RouteType.PROVIDER, null);    } else if (types.isSubtype(tm, type_Service)) {           // Service 类型        logger.info(">>> Found service route: " + tm.toString() + " <<<");        routeMeta = new RouteMeta(route, element, RouteType.parse(SERVICE), null);    } else if (types.isSubtype(tm, fragmentTm) || types.isSubtype(tm, fragmentTmV4)) { // fragment 类型        logger.info(">>> Found fragment route: " + tm.toString() + " <<<");        routeMeta = new RouteMeta(route, element, RouteType.parse(FRAGMENT), null);    } else {        throw new RuntimeException("ARouter::Compiler >>> Found unsupported class type, type = [" + types.toString() + "].");    }    // 将生成好的 routeMeta 按组存放进入 groupMap 中    categories(routeMeta);}

上面这段代码主要将每个 routeElement 进行了分类，将 @Route 修饰的类信息封装进 RouteMeta 中。再把 RouteMeta 按照组名分好组存进 groupMap 中。

// 构造 ARouter$$Providers$$xxx 的 loadInto 方法MethodSpec.Builder loadIntoMethodOfProviderBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)        .addAnnotation(Override.class)        .addModifiers(PUBLIC)        .addParameter(providerParamSpec);Map<String, List<RouteDoc>> docSource = new HashMap<>();// Start generate java source, structure is divided into upper and lower levels, used for demand initialization.for (Map.Entry<String, Set<RouteMeta>> entry : groupMap.entrySet()) {    // 每组的组名    String groupName = entry.getKey();    // 构造 ARouter$$Group$$xxx 的 loadInto 方法    MethodSpec.Builder loadIntoMethodOfGroupBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)            .addAnnotation(Override.class)            .addModifiers(PUBLIC)            .addParameter(groupParamSpec);    List<RouteDoc> routeDocList = new ArrayList<>();    // Build group method body    Set<RouteMeta> groupData = entry.getValue();    for (RouteMeta routeMeta : groupData) {        RouteDoc routeDoc = extractDocInfo(routeMeta);        // 类名。比方 com.alibaba.android.arouter.demo.testservice.HelloService        ClassName className = ClassName.get((TypeElement) routeMeta.getRawType());        switch (routeMeta.getType()) {            case PROVIDER:  // Need cache provider's super class                // 获取该节点下的接口                List<? extends TypeMirror> interfaces = ((TypeElement) routeMeta.getRawType()).getInterfaces();                // 遍历接口                for (TypeMirror tm : interfaces) {                    routeDoc.addPrototype(tm.toString());                    // 假如接口是 iProvider 类型                    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, $S, null, " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",                                (routeMeta.getRawType()).toString(),                                routeMetaCn,                                routeTypeCn,                                className,                                routeMeta.getPath(),                                routeMeta.getGroup());                    } else if (types.isSubtype(tm, iProvider)) { // 假如是 iProvider 的子接口                        // This interface extend the IProvider, so it can be used for mark provider                        loadIntoMethodOfProviderBuilder.addStatement(                                "providers.put($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;        }

上面的代码最终会生成 ARouterxxx 的 loadInto 方法，比方像这样：

providers.put("com.alibaba.android.arouter.demo.testservice.HelloService", RouteMeta.build(RouteType.PROVIDER, HelloServiceImpl.class, "/yourservicegroupname/hello", "yourservicegroupname", null, -1, -2147483648));

那我们接着看。

    // 构造 RouteMeta 的 paramType 参数    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();    // 以下代码生成这种模版 atlas.put("/test/activity1", RouteMeta.build(RouteType.ACTIVITY, Test1Activity.class, "/test/activity1", "test", new java.util.HashMap<String, Integer>(){{put("ser", 9); }}, -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);}// 生成 ARouter$$Group$$xxx 类String groupFileName = NAME_OF_GROUP + groupName;JavaFile.builder(PACKAGE_OF_GENERATE_FILE,        TypeSpec.classBuilder(groupFileName)                .addJavadoc(WARNING_TIPS)                .addSuperinterface(ClassName.get(type_IRouteGroup))                .addModifiers(PUBLIC)                .addMethod(loadIntoMethodOfGroupBuilder.build())                .build()).build().writeTo(mFiler);logger.info(">>> Generated group: " + groupName + "<<<");rootMap.put(groupName, groupFileName);docSource.put(groupName, routeDocList);

上面代码主要做的事情就是遍历 groupmap 集合给 ARouterxxx 类中的 loadInto 增加方法体，并生成 java 文件。

if (MapUtils.isNotEmpty(rootMap)) {    // Generate root meta by group name, it must be generated before root, then I can find out the class of group.    // 生成 ARouter$$Root$$app 的 loadInto 方法体    for (Map.Entry<String, String> entry : rootMap.entrySet()) {        loadIntoMethodOfRootBuilder.addStatement("routes.put($S, $T.class)", entry.getKey(), ClassName.get(PACKAGE_OF_GENERATE_FILE, entry.getValue()));    }}// Output route docif (generateDoc) {    docWriter.append(JSON.toJSONString(docSource, SerializerFeature.PrettyFormat));    docWriter.flush();    docWriter.close();}// 生成 ARouter$$Providers$$app 类String providerMapFileName = NAME_OF_PROVIDER + SEPARATOR + moduleName;JavaFile.builder(PACKAGE_OF_GENERATE_FILE,        TypeSpec.classBuilder(providerMapFileName)                .addJavadoc(WARNING_TIPS)                .addSuperinterface(ClassName.get(type_IProviderGroup))                .addModifiers(PUBLIC)                .addMethod(loadIntoMethodOfProviderBuilder.build())                .build()).build().writeTo(mFiler);logger.info(">>> Generated provider map, name is " + providerMapFileName + " <<<");// 生成 ARouter$$Root$$app 类 String rootFileName = NAME_OF_ROOT + SEPARATOR + moduleName;JavaFile.builder(PACKAGE_OF_GENERATE_FILE,        TypeSpec.classBuilder(rootFileName)                .addJavadoc(WARNING_TIPS)                .addSuperinterface(ClassName.get(elements.getTypeElement(ITROUTE_ROOT)))                .addModifiers(PUBLIC)                .addMethod(loadIntoMethodOfRootBuilder.build())                .build()).build().writeTo(mFiler);logger.info(">>> Generated root, name is " + rootFileName + " <<<");

以上，就是整个 RouteProcessor 的流程。看完 RouteProcessor 之后，相信你对 ARouter 的的理解也更加深入了。

之后，也会对 ARouter 的 arouter-register 板块做一个深入解析，敬请期待吧。