阿里路由框架ARouter 源碼解析之Compiler

更新時(shí)間：2018年07月02日 14:02:17 作者：Jack_sen

這篇文章主要介紹了阿里路由框架ARouter 源碼解析之Compiler,小編覺得挺不錯(cuò)的，現(xiàn)在分享給大家，也給大家做個(gè)參考。一起跟隨小編過來看看吧

前段時(shí)間，公司項(xiàng)目在做組件化重構(gòu)，過程中當(dāng)然會(huì)有很多痛點(diǎn)。

組件化最重要的是根據(jù)項(xiàng)目和業(yè)務(wù)進(jìn)行分模塊，至于模塊的粒度就看大家自己來把控了！

這里要說的就是模塊之間的數(shù)據(jù)傳輸問題

組件化之后，各個(gè)模塊不相互依賴，那么怎么相互跳轉(zhuǎn)和傳遞數(shù)據(jù)呢？

答案就是通過隱式Intent 的方式來跳轉(zhuǎn)和傳遞數(shù)據(jù)。

以往的顯示Intent 跳轉(zhuǎn)，會(huì)存在類直接依賴的問題，這樣會(huì)導(dǎo)致耦合性非常嚴(yán)重；相比而言，隱式Intent則不需要類之間的直接依賴，但是會(huì)出現(xiàn)規(guī)則集中式管理，擴(kuò)展性比較差。

所以在調(diào)研期間就發(fā)現(xiàn)阿里開源了ARouter–路由框架。

ARouter的好處我這里就不多說，大家可以去看官方文檔或者去github上看README。

【https://github.com/alibaba/ARouter】

接下來會(huì)分為若干篇blog來分析一下ARouter的源碼！

看了ARouter的源碼就會(huì)發(fā)現(xiàn)，它提供了兩個(gè)SDK，一個(gè)是API，一個(gè)Compiler。

Compiler SDK 是用于編譯器生成相關(guān)類文件的。
API SDK 是用在運(yùn)行期間路由跳轉(zhuǎn)等作用的。

這里先說說Compiler層SDK。

RouteProcessor 路由路徑處理器

InterceptorProcessor 攔截器處理器

AutowireProcessor 自動(dòng)裝配處理器

注解處理器的處理流程

（圖片轉(zhuǎn)自網(wǎng)絡(luò)）

實(shí)際上，Compiler SDK 只是處根據(jù)掃描到的注解生成相應(yīng)的映射(java)文件。

最后一步通過固定包名加載映射文件是由API SDK來做的。

以官方demo為例來說：

上圖所示就是ARouter在編譯期間生成的類文件。

紅色標(biāo)注的是 RouteProcessor 生成的類文件
藍(lán)色標(biāo)注的是 InterceptorProcessor 生成的類文件
橙色標(biāo)書的是 AutowiredProcessor 生成的類文件

arouter-compiler的目錄結(jié)構(gòu)如下：

processor包下面是注解處理器
utils包下面是相關(guān)工具類

下面分別說說這三種注解處理器：

用過編譯時(shí)注解的朋友們都知道，注解處理器需要繼承AbstractProcessor ，主要涉及的函數(shù)有 init()，process() 這兩個(gè)。

RouteProcessor

類的繼承信息：

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

init

init()

 // 初始化處理器
 @Override
 public synchronized void init(ProcessingEnvironment processingEnv) {
  super.init(processingEnv);

  // 文件管理器
  mFiler = processingEnv.getFiler();     // Generate class.
  // 獲取類型處理工具類
  types = processingEnv.getTypeUtils();   // Get type utils.
  // 獲取日志信息工具類
  elements = processingEnv.getElementUtils();  // Get class meta.

  typeUtils = new TypeUtils(types, elements);
  // 封裝日志信息類
  logger = new Logger(processingEnv.getMessager()); // Package the log utils.

  // 獲取用戶配置的[moduleName]
  Map<String, String> options = processingEnv.getOptions();
  if (MapUtils.isNotEmpty(options)) {
   moduleName = options.get(KEY_MODULE_NAME);
  }

  if (StringUtils.isNotEmpty(moduleName)) {
   // 格式化
   moduleName = moduleName.replaceAll("[^0-9a-zA-Z_]+", "");

   logger.info("The user has configuration the module name, it was [" + moduleName + "]");
  } else {
   // 如果沒有在build.gradle中配置moduleName，則會(huì)拋出異常。
   logger.error("These no module name, at 'build.gradle', like :\n" +
     "apt {\n" +
     " arguments {\n" +
     "  moduleName project.getName();\n" +
     " }\n" +
     "}\n");
   throw new RuntimeException("ARouter::Compiler >>> No module name, for more information, look at gradle log.");
  }

  // 
  iProvider = elements.getTypeElement(Consts.IPROVIDER).asType();
  // RouterProcessor 初始化完畢
  logger.info(">>> RouteProcessor init. <<<");
 }

// Consts.java
public static final String KEY_MODULE_NAME = "moduleName";

在使用ARouter注解的時(shí)候，按照官方文檔是需要在每個(gè)module里面的build.gradle中配置如下信息：

javaCompileOptions {
   annotationProcessorOptions {
    arguments = [ moduleName : project.getName() ]
   }
  }

配置這個(gè)屬性的目的，就是為了在編譯期間生成相關(guān)module下的文件和存儲(chǔ)文件名稱。

process()

一般在process()函數(shù)中做的操作如下：

遍歷注解的元素
檢驗(yàn)元素是否符合要求（過濾元素）
獲取輸出類參數(shù)
生成映射文件（java文件）
錯(cuò)誤處理

 @Override
 public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
  if (CollectionUtils.isNotEmpty(annotations)) {
   // 獲取所有添加Route注解的元素
   Set<? extends Element> routeElements = roundEnv.getElementsAnnotatedWith(Route.class);
   try {
    logger.info(">>> Found routes, start... <<<");
    // 調(diào)用arseRoute()函數(shù)進(jìn)行處理獲取的注解元素集合
    this.parseRoutes(routeElements);

   } catch (Exception e) {
    logger.error(e);
   }
   // 如果有Route元素的注解，并且處理過程中無異常則返回true
   return true;
  }
  // 否則返回false
  return false;
 }

parseRoutes()

這個(gè)函數(shù)的代碼有點(diǎn)長，大家耐心看！

 // Consts.java

 public static final String ACTIVITY = "android.app.Activity";
 public static final String FRAGMENT = "android.app.Fragment";
 public static final String FRAGMENT_V4 = "android.support.v4.app.Fragment";
 public static final String SERVICE = "android.app.Service";

 private static final String FACADE_PACKAGE = "com.alibaba.android.arouter.facade";
 private static final String TEMPLATE_PACKAGE = ".template";

 public static final String IROUTE_GROUP = FACADE_PACKAGE + TEMPLATE_PACKAGE + ".IRouteGroup";

 public static final String IPROVIDER_GROUP = FACADE_PACKAGE + TEMPLATE_PACKAGE + ".IProviderGroup";

private void parseRoutes(Set<? extends Element> routeElements) throws IOException {
  if (CollectionUtils.isNotEmpty(routeElements)) {
   // ...

   rootMap.clear();

   // 獲取ACTIVITY, SERVICE, FRAGMENT, FRAGMENT_V4 這四種 類型鏡像
   TypeMirror type_Activity = elements.getTypeElement(ACTIVITY).asType();
   TypeMirror type_Service = elements.getTypeElement(SERVICE).asType();
   TypeMirror fragmentTm = elements.getTypeElement(FRAGMENT).asType();
   TypeMirror fragmentTmV4 = elements.getTypeElement(Consts.FRAGMENT_V4).asType();

   // ARouter的接口
   TypeElement type_IRouteGroup = elements.getTypeElement(IROUTE_GROUP);
   TypeElement type_IProviderGroup = elements.getTypeElement(IPROVIDER_GROUP);

   // 
   // 下面就是遍歷獲取的注解信息，通過javapoet來生成類文件了 

   ClassName routeMetaCn = ClassName.get(RouteMeta.class);
   ClassName routeTypeCn = ClassName.get(RouteType.class);

   /*
    ParameterizedTypeName用來創(chuàng)建類型對象，例如下面

    ```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))
     )
   );

   /*
    RouteMeta封裝了路由相關(guān)的信息

    ```Map<String, RouteMeta>```
    */
   ParameterizedTypeName inputMapTypeOfGroup = ParameterizedTypeName.get(
     ClassName.get(Map.class),
     ClassName.get(String.class),
     ClassName.get(RouteMeta.class)
   );

   /*
    創(chuàng)建輸入?yún)?shù)
    */

   // 1。 生成的參數(shù)：Map<String, Class<? extends IRouteGroup>> routes
   ParameterSpec rootParamSpec = ParameterSpec.builder(inputMapTypeOfRoot, "routes").build(); // 第一個(gè)參數(shù)表示參數(shù)類型，第二個(gè)函數(shù)表示參數(shù)名稱

   // 2。 Map<String, RouteMeta> atlas
   ParameterSpec groupParamSpec = ParameterSpec.builder(inputMapTypeOfGroup, "atlas").build();

   // 3。 Map<String, RouteMeta> providers
   ParameterSpec providerParamSpec = ParameterSpec.builder(inputMapTypeOfGroup, "providers").build(); 

   // MethodSpec用來創(chuàng)建方法

   // public static final String METHOD_LOAD_INTO = "loadInto";
   /*
    Build method : 'loadInto'
    */
   MethodSpec.Builder loadIntoMethodOfRootBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
     .addAnnotation(Override.class) // override
     .addModifiers(PUBLIC) // public
     .addParameter(rootParamSpec); // 參數(shù)

   // 創(chuàng)建出來的函數(shù)如下
   /**
    * @Override
    * public void loadInto(Map<String, Class<? extends IRouteGroup>> routes) { } 
    */ 

   //

   // 接下來的代碼就是遍歷注解元素，進(jìn)行分組，進(jìn)而聲稱java文件

   for (Element element : routeElements) { // 遍歷每個(gè)元素

    TypeMirror tm = element.asType();
    Route route = element.getAnnotation(Route.class);
    RouteMeta routeMete = null;

    // 判斷類型
    if (types.isSubtype(tm, type_Activity)) { // Activity
     logger.info(">>> Found activity route: " + tm.toString() + " <<<");

     Map<String, Integer> paramsType = new HashMap<>();

     // 遍歷查找所有添加 @AutoWired 注解的變量
     for (Element field : element.getEnclosedElements()) {

      // 1. 必須是field
      // 2. 必須有注解AutoWired
      // 3. 必須不是IProvider類型

      if (field.getKind().isField() && field.getAnnotation(Autowired.class) != null && !types.isSubtype(field.asType(), iProvider)) {
       // 滿足上述條件后，獲取注解
       Autowired paramConfig = field.getAnnotation(Autowired.class);

       // 看過源碼就知道，Autowired支持寫別名，當(dāng)指定name屬性之后，就會(huì)以name為準(zhǔn)，否則以field的名字為準(zhǔn)。
       // TypeUtils是自定義工具類，用來判斷field的數(shù)據(jù)類型的，轉(zhuǎn)換成int值。

       paramsType.put(StringUtils.isEmpty(paramConfig.name()) ? field.getSimpleName().toString() : paramConfig.name(), typeUtils.typeExchange(field));
      }

     // 構(gòu)建一條路由信息，將字段注解信息保存進(jìn)去

     routeMete = new RouteMeta(route, element, RouteType.ACTIVITY, paramsType);
    } 

    // 如果是IProvider類型的注解，則直接創(chuàng)建一條PROVIDER類型的路由信息
    else if (types.isSubtype(tm, iProvider)) {   
     routeMete = new RouteMeta(route, element, RouteType.PROVIDER, null);
    } 
    // 如果是Service類型的注解，則直接創(chuàng)建一條Service類型的路由信息
    else if (types.isSubtype(tm, type_Service)) {   // Service
     routeMete = new RouteMeta(route, element, RouteType.parse(Service), null);
    } 
    // 如果是fragmentTmV4類型的注解，則直接創(chuàng)建一條Fragment類型的路由信息
    else if (types.isSubtype(tm, fragmentTm) || types.isSubtype(tm, fragmentTmV4)) {
     routeMete = new RouteMeta(route, element, RouteType.parse(FRAGMENT), null);
    }

    // 將路由信息進(jìn)行分組 （每個(gè)路由信息對象中都保存著它所屬的組別信息，在調(diào)用categories()函數(shù)之前所有的組別信息都是默認(rèn)值"" ）
    categories(routeMete);

   }

   // 第一次遍歷之前，已經(jīng)創(chuàng)建了ROOT類的loadInto函數(shù)
   // 下面開始創(chuàng)建Provider類的loadInto函數(shù)
   MethodSpec.Builder loadIntoMethodOfProviderBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
     .addAnnotation(Override.class)
     .addModifiers(PUBLIC)
     .addParameter(providerParamSpec);

   // 創(chuàng)建出來的函數(shù)如下
   /**
    * @Override
    * public void loadInto(Map<String, RouteMeta> providers) { } 
    */   

   // 接著，遍歷所有在 categories(routeMete); 得到的所有組別

   for (Map.Entry<String, Set<RouteMeta>> entry : groupMap.entrySet()) {
    String groupName = entry.getKey();

    // 創(chuàng)建分組類的函數(shù) -- loadInto(Map<String, RouteMeta> atlas)
    MethodSpec.Builder loadIntoMethodOfGroupBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
      .addAnnotation(Override.class)
      .addModifiers(PUBLIC)
      .addParameter(groupParamSpec);

    // 往組別函數(shù)loadInto中添加數(shù)據(jù)
    Set<RouteMeta> groupData = entry.getValue();

    // PROVIDERL 類型的數(shù)據(jù)需要特殊處理

    for (RouteMeta routeMeta : groupData) {
     switch (routeMeta.getType()) {
      case PROVIDER: 

       List<? extends TypeMirror> interfaces = ((TypeElement) routeMeta.getRawType()).getInterfaces();
       // 遍歷當(dāng)前類的接口
       for (TypeMirror tm : interfaces) {
        // 如果當(dāng)前類直接實(shí)現(xiàn)了IProvider接口
        if (types.isSameType(tm, iProvider)) { 

   // 這種情況下，在loadInfo()函數(shù)里面添加的語句類似于：
   // singleService直接實(shí)現(xiàn)IProvider接口

   /**
    * @Route(path = "/service/single")
    * public class SingleService implements IProvider
    * 
    * providers.put("com.alibaba.android.arouter.demo.testservice.SingleService", RouteMeta.build(RouteType.PROVIDER, SingleService.class, "/service/single", "service", null, -1, -2147483648)); 
    */         

         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.get((TypeElement) routeMeta.getRawType()),
           routeMeta.getPath(),
           routeMeta.getGroup());

        } else if (types.isSubtype(tm, iProvider)) {
         // 如果是接口繼承的IProvider

   // 這種情況下，在loadInfo()函數(shù)里面添加的語句類似于：
   // singleService直接實(shí)現(xiàn)IProvider接口

   /**
    * @Route(path = "/service/hello")
    * public class HelloServiceImpl implements HelloService 
    * public interface HelloService extends IProvider
    * //
    * providers.put("com.alibaba.android.arouter.demo.testservice.HelloService", RouteMeta.build(RouteType.PROVIDER, HelloServiceImpl.class, "/service/hello", "service", null, -1, -2147483648)); 
    */            

         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.get((TypeElement) routeMeta.getRawType()),
           routeMeta.getPath(),
           routeMeta.getGroup());
        }
       }
       break;
      default:
       break;
     }

     // 拼接添加注解的字段

     StringBuilder mapBodyBuilder = new StringBuilder();
     Map<String, Integer> paramsType = routeMeta.getParamsType();
     if (MapUtils.isNotEmpty(paramsType)) {
      for (Map.Entry<String, Integer> types : paramsType.entrySet()) {
       mapBodyBuilder.append("put(\"").append(types.getKey()).append("\", ").append(types.getValue()).append("); ");
      }
     }
     // // 形式如： put("pac", 9); put("obj", 10);
     String mapBody = mapBodyBuilder.toString();

     // 往loadInto函數(shù)里面添加一個(gè)語句
     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(), // 完整路徑
       routeMetaCn, // RouteMeta
       routeTypeCn, // RouteType
       ClassName.get((TypeElement) routeMeta.getRawType()), // 注解原生類的名稱
       routeMeta.getPath().toLowerCase(), // 完整路徑
       routeMeta.getGroup().toLowerCase()); // 組名
    }

    // 添加的語句如下：
    // atlas.put("/test/activity1", RouteMeta.build(RouteType.ACTIVITY, Test1Activity.class, "/test/activity1", "test", new java.util.HashMap<String, Integer>(){{put("pac", 9); put("obj", 10); put("name", 8); put("boy", 0); put("age", 3); put("url", 8); }}, -1, -2147483648));

    // 生成組類別java文件
    // public static final String NAME_OF_GROUP = PROJECT + SEPARATOR + "Group" + SEPARATOR;
    // public static final String SEPARATOR = "$$";
    // public static final String PROJECT = "ARouter";
    String groupFileName = NAME_OF_GROUP + groupName;

    JavaFile.builder(PACKAGE_OF_GENERATE_FILE, // package 名稱 --"com.alibaba.android.arouter.routes"
      TypeSpec.classBuilder(groupFileName) //java類名
        .addJavadoc(WARNING_TIPS) // doc
        .addSuperinterface(ClassName.get(type_IRouteGroup)) // 添加繼承的接口
        .addModifiers(PUBLIC) //　作用域?yàn)閜ublic
        .addMethod(loadIntoMethodOfGroupBuilder.build()) // 添加函數(shù)（包括了函數(shù)里面的代碼塊）
        .build()
    ).build().writeTo(mFiler);

    // 將組名和組文件名放到map中，方便按需加載
    rootMap.put(groupName, groupFileName);
   }

  // .................................................................... //


   // 經(jīng)過了上面的for循環(huán)，生成了如 ARouter$$Group$$service.java 和ARouter$$Group$$test.java 文件，它們所在的包是 com.alibaba.android.arouter.routes。

   if (MapUtils.isNotEmpty(rootMap)) {
    // 遍歷這些group，進(jìn)而生成Root類文件
    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()));

     // 每一個(gè)statement如： routes.put("test", ARouter$$Group$$test.class);
    }
   }

   // 生成provider類文件

   // provider文件名為：ARouter$$Providers$$xxx
   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);


   // 生成root文件
   // ARouter$$Root$$xxx
   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);


  }
 }

categories()

下面來看一下怎么講路由進(jìn)行分組的

private void categories(RouteMeta routeMete) {
  // 首先去驗(yàn)證這條路由信息
  if (routeVerify(routeMete)) {
   // 嘗試從groupMap中通過group名稱獲取路由信息
   Set<RouteMeta> routeMetas = groupMap.get(routeMete.getGroup());
   if (CollectionUtils.isEmpty(routeMetas)) { // 如果map中沒有相關(guān)記錄，則表示這個(gè)組別還未添加到map中
    Set<RouteMeta> routeMetaSet = new TreeSet<>(new Comparator<RouteMeta>() {
     @Override
     public int compare(RouteMeta r1, RouteMeta r2) {
      try {
       return r1.getPath().compareTo(r2.getPath());
      } catch (NullPointerException npe) {
       logger.error(npe.getMessage());
       return 0;
      }
     }
    });
    // 添加該組別到map中
    routeMetaSet.add(routeMete);
    groupMap.put(routeMete.getGroup(), routeMetaSet);
   } else { // 如果存在該組別則添加到這一組中
    routeMetas.add(routeMete);
   }
  } else {
   // 驗(yàn)證路由信息不正確是會(huì)在編譯期間輸出錯(cuò)誤日志
   logger.warning(">>> Route meta verify error, group is " + routeMete.getGroup() + " <<<");
  }
 }

routeVerify()

// 驗(yàn)證路由信息的正確性
private boolean routeVerify(RouteMeta meta) {
  String path = meta.getPath();
  // 判斷路徑是否為空或者是否以“/”開頭
  if (StringUtils.isEmpty(path) || !path.startsWith("/")) { // The path must be start with '/' and not empty!
   return false;
  }
  // 沒有分組時(shí)，group為""
  if (StringUtils.isEmpty(meta.getGroup())) { // Use default group(the first word in path)
   try {
    // 截取字符串獲取group
    String defaultGroup = path.substring(1, path.indexOf("/", 1));
    if (StringUtils.isEmpty(defaultGroup)) {
     return false;
    }

    meta.setGroup(defaultGroup);
    return true;
   } catch (Exception e) {
    logger.error("Failed to extract default group! " + e.getMessage());
    return false;
   }
  }

  return true;
 }

通過上面的分析可以得到以下幾點(diǎn)：

配置Route注解時(shí)，路徑不允許為空且必須以“/”開頭

RouteProcessor注解處理器生成的文件由三種：

1. ARouter$$Group$$xxx (可能有多個(gè))
2. ARouter$$Providers$$xxx (只有一個(gè))
3. ARouter$$Root$$xxx (只有一個(gè))

InterceptorProcessor

@AutoService(Processor.class)
@SupportedOptions(KEY_MODULE_NAME)
@SupportedSourceVersion(SourceVersion.RELEASE_7)
@SupportedAnnotationTypes(ANNOTATION_TYPE_INTECEPTOR)
public class InterceptorProcessor extends AbstractProcessor

init()

 @Override
 public synchronized void init(ProcessingEnvironment processingEnv) {
  super.init(processingEnv);

  // ... 省略代碼與RouteProcressor基本一樣

  iInterceptor = elementUtil.getTypeElement(Consts.IINTERCEPTOR).asType();
 }

process()

 @Override
 public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
  if (CollectionUtils.isNotEmpty(annotations)) {
   // 獲取Interceptor注解的集合
   Set<? extends Element> elements = roundEnv.getElementsAnnotatedWith(Interceptor.class);
   try {
    // 處理注解信息
    parseInterceptors(elements);
   } catch (Exception e) {
    logger.error(e);
   }
   return true;
  }

  return false;
 }

parseInterceptors()

private Map<Integer, Element> interceptors = new TreeMap<>();

private void parseInterceptors(Set<? extends Element> elements) throws IOException {
  if (CollectionUtils.isNotEmpty(elements)) {
   // 遍歷注解元素
   for (Element element : elements) {
    if (verify(element)) { // 做驗(yàn)證

     Interceptor interceptor = element.getAnnotation(Interceptor.class);
     // 嘗試從攔截器結(jié)合中根據(jù)優(yōu)先級獲取
     Element lastInterceptor = interceptors.get(interceptor.priority());

     // 如果是已經(jīng)存在相同優(yōu)先級的攔截器，就會(huì)拋出異常
     if (null != lastInterceptor) { 
      throw new IllegalArgumentException(
        String.format(Locale.getDefault(), "More than one interceptors use same priority [%d], They are [%s] and [%s].",
          interceptor.priority(),
          lastInterceptor.getSimpleName(),
          element.getSimpleName())
      );
     }
     // 添加到集合中
     interceptors.put(interceptor.priority(), element);
    } else {
     logger.error("A interceptor verify failed, its " + element.asType());
    }
   }

   // Interface of ARouter.
   TypeElement type_ITollgate = elementUtil.getTypeElement(IINTERCEPTOR);
   TypeElement type_ITollgateGroup = elementUtil.getTypeElement(IINTERCEPTOR_GROUP);

   /**
    * 創(chuàng)建類型對象
    *
    * ```Map<Integer, Class<? extends IInterceptor>>```
    */
   ParameterizedTypeName inputMapTypeOfTollgate = ParameterizedTypeName.get(
     ClassName.get(Map.class),
     ClassName.get(Integer.class),
     ParameterizedTypeName.get(
       ClassName.get(Class.class),
       WildcardTypeName.subtypeOf(ClassName.get(type_ITollgate))
     )
   );

   // 構(gòu)建輸入?yún)?shù)
   ParameterSpec tollgateParamSpec = ParameterSpec.builder(inputMapTypeOfTollgate, "interceptors").build();

   // 創(chuàng)建函數(shù) : 'loadInto'
   MethodSpec.Builder loadIntoMethodOfTollgateBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
     .addAnnotation(Override.class)
     .addModifiers(PUBLIC)
     .addParameter(tollgateParamSpec);

   // 遍歷攔截器結(jié)合，往loadInto函數(shù)中添加語句
   if (null != interceptors && interceptors.size() > 0) {
    // Build method body
    for (Map.Entry<Integer, Element> entry : interceptors.entrySet()) {
     loadIntoMethodOfTollgateBuilder.addStatement("interceptors.put(" + entry.getKey() + ", $T.class)", ClassName.get((TypeElement) entry.getValue()));

    // 語句類似于
    // interceptors.put(1, Test1Interceptor.class);
    }
   }

   // 寫入文件
   JavaFile.builder(PACKAGE_OF_GENERATE_FILE,
     TypeSpec.classBuilder(NAME_OF_INTERCEPTOR + SEPARATOR + moduleName)
       .addModifiers(PUBLIC)
       .addJavadoc(WARNING_TIPS)
       .addMethod(loadIntoMethodOfTollgateBuilder.build())
       .addSuperinterface(ClassName.get(type_ITollgateGroup))
       .build()
   ).build().writeTo(mFiler);

   logger.info(">>> Interceptor group write over. <<<");
  }
 }

verify()

// 驗(yàn)證注解元素是否合格
private boolean verify(Element element) {
  Interceptor interceptor = element.getAnnotation(Interceptor.class);
  return null != interceptor && ((TypeElement)element).getInterfaces().contains(iInterceptor);
 }

通過上面的分析可以得到以下幾點(diǎn)：

不能設(shè)置相同優(yōu)先級的攔截器，否則會(huì)拋出異常

InterceptorProcessor生成的類文件格式為：ARouter$$Interceptors$$xxx

AutowiredProcessor

@AutoService(Processor.class)
@SupportedOptions(KEY_MODULE_NAME)
@SupportedSourceVersion(SourceVersion.RELEASE_7)
@SupportedAnnotationTypes({ANNOTATION_TYPE_AUTOWIRED})
public class AutowiredProcessor extends AbstractProcessor

init()

 @Override
 public synchronized void init(ProcessingEnvironment processingEnvironment) {
  super.init(processingEnvironment);

  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.
 }

process()

 // process函數(shù)主要關(guān)注兩點(diǎn) categories() 和 generateHelper()
 @Override
 public boolean process(Set<? extends TypeElement> set, RoundEnvironment roundEnvironment) {
  if (CollectionUtils.isNotEmpty(set)) {
   try {
    logger.info(">>> Found autowired field, start... <<<");
    // 1. 分組
    categories(roundEnvironment.getElementsAnnotatedWith(Autowired.class));
    // 2. 
    generateHelper();

   } catch (Exception e) {
    logger.error(e);
   }
   return true;
  }

  return false;
 }

categories

private Map<TypeElement, List<Element>> parentAndChild = new HashMap<>();

// 將注解元素分組
private void categories(Set<? extends Element> elements) throws IllegalAccessException {
  if (CollectionUtils.isNotEmpty(elements)) {
   for (Element element : elements) { // 遍歷
    // 獲取注解字段所在的類信息
    TypeElement enclosingElement = (TypeElement) element.getEnclosingElement();
    // 注解的字段不能為private，否則拋出異常
    if (element.getModifiers().contains(Modifier.PRIVATE)) {
     throw new IllegalAccessException("The autowired fields CAN NOT BE 'private'!!! please check field ["
       + element.getSimpleName() + "] in class [" + enclosingElement.getQualifiedName() + "]");
    }
    // 判斷集合中是否存在集合中
    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.");
  }
 }

generateHelper

 // 
 private void generateHelper() throws IOException, IllegalAccessException {
  // ISyringe
  TypeElement type_ISyringe = elements.getTypeElement(ISYRINGE);
  // SerializationService
  TypeElement type_JsonService = elements.getTypeElement(JSON_SERVICE);

  TypeMirror iProvider = elements.getTypeElement(Consts.IPROVIDER).asType();
  TypeMirror activityTm = elements.getTypeElement(Consts.ACTIVITY).asType();
  TypeMirror fragmentTm = elements.getTypeElement(Consts.FRAGMENT).asType();
  TypeMirror fragmentTmV4 = elements.getTypeElement(Consts.FRAGMENT_V4).asType();

  // 構(gòu)建輸入?yún)?shù)
  ParameterSpec objectParamSpec = ParameterSpec.builder(TypeName.OBJECT, "target").build();
  // 遍歷分組的集合
  if (MapUtils.isNotEmpty(parentAndChild)) {
   for (Map.Entry<TypeElement, List<Element>> entry : parentAndChild.entrySet()) {
    // 構(gòu)建函數(shù) : 'inject'
    MethodSpec.Builder injectMethodBuilder = MethodSpec.methodBuilder(METHOD_INJECT)
      .addAnnotation(Override.class)
      .addModifiers(PUBLIC)
      .addParameter(objectParamSpec); // 添加參數(shù)

    TypeElement parent = entry.getKey();
    List<Element> childs = entry.getValue();

    String qualifiedName = parent.getQualifiedName().toString();
    String packageName = qualifiedName.substring(0, qualifiedName.lastIndexOf("."));

    // 文件名稱例如：Test1Activity$$ARouter$$Autowired
    String fileName = parent.getSimpleName() + NAME_OF_AUTOWIRED;

    // 
    TypeSpec.Builder helper = TypeSpec.classBuilder(fileName)
      .addJavadoc(WARNING_TIPS)
      .addSuperinterface(ClassName.get(type_ISyringe))
      .addModifiers(PUBLIC);
    // 構(gòu)建SerializationService 字段
    FieldSpec jsonServiceField = FieldSpec.builder(TypeName.get(type_JsonService.asType()), "serializationService", Modifier.PRIVATE).build();
    // 添加字段
    helper.addField(jsonServiceField);
    // inject函數(shù)中添加語句
    // serializationService = ARouter.getInstance().navigation(SerializationService.class);

    injectMethodBuilder.addStatement("serializationService = $T.getInstance().navigation($T.class);", ARouterClass, ClassName.get(type_JsonService));

    // 轉(zhuǎn)換對象
    // 比如：Test1Activity substitute = (Test1Activity)target;
    injectMethodBuilder.addStatement("$T substitute = ($T)target", ClassName.get(parent), ClassName.get(parent));

    // 遍歷注解變量
    for (Element element : childs) {
     Autowired fieldConfig = element.getAnnotation(Autowired.class);
     String fieldName = element.getSimpleName().toString();

     // 判斷是否是IProvider類型
     if (types.isSubtype(element.asType(), iProvider)) { 
      // 如果name為空，則通過Type方式
      if ("".equals(fieldConfig.name())) { 

       injectMethodBuilder.addStatement(
         "substitute." + fieldName + " = $T.getInstance().navigation($T.class)",
         ARouterClass,
         ClassName.get(element.asType())
       );
      } else { // 如果name不為空，則通過name方式

       injectMethodBuilder.addStatement(
         "substitute." + fieldName + " = ($T)$T.getInstance().build($S).navigation();",
         ClassName.get(element.asType()),
         ARouterClass,
         fieldConfig.name()
       );
      }

      // 是否是必須傳值字段，這里加入了if判斷
      if (fieldConfig.required()) {
       injectMethodBuilder.beginControlFlow("if (substitute." + fieldName + " == null)");
       injectMethodBuilder.addStatement(
         "throw new RuntimeException(\"The field '" + fieldName + "' is null, in class '\" + $T.class.getName() + \"!\")", ClassName.get(parent));
       injectMethodBuilder.endControlFlow();
      }
     } else { // It's normal intent value
      String statment = "substitute." + fieldName + " = substitute.";
      boolean isActivity = false;
      // Activity類型時(shí)，通過 getIntent() 方式

      if (types.isSubtype(parent.asType(), activityTm)) { 
       isActivity = true;
       statment += "getIntent().";
      }
      // Fragment類型, 使用 getArguments()
       else if (types.isSubtype(parent.asType(), fragmentTm) || types.isSubtype(parent.asType(), fragmentTmV4)) { 
       statment += "getArguments().";
      } 
      // 非Activity或者非Fragment，則拋出異常
      else {
       throw new IllegalAccessException("The field [" + fieldName + "] need autowired from intent, its parent must be activity or fragment!");
      }

      statment = buildStatement(statment, typeUtils.typeExchange(element), isActivity);

      // 針對SerializationService添加判空操作
      if (statment.startsWith("serializationService.")) { // Not mortals
       injectMethodBuilder.beginControlFlow("if (null != serializationService)");
       injectMethodBuilder.addStatement(
         "substitute." + fieldName + " = " + statment,
         (StringUtils.isEmpty(fieldConfig.name()) ? fieldName : fieldConfig.name()),
         ClassName.get(element.asType())
       );
       injectMethodBuilder.nextControlFlow("else");
       injectMethodBuilder.addStatement(
         "$T.e(\"" + Consts.TAG + "\", \"You want automatic inject the field '" + fieldName + "' in class '$T' , then you should implement 'SerializationService' to support object auto inject!\")", AndroidLog, ClassName.get(parent));
       injectMethodBuilder.endControlFlow();
      } else {
       injectMethodBuilder.addStatement(statment, StringUtils.isEmpty(fieldConfig.name()) ? fieldName : fieldConfig.name());
      }

      // Validator
      if (fieldConfig.required() && !element.asType().getKind().isPrimitive()) { // Primitive wont be check.
       injectMethodBuilder.beginControlFlow("if (null == substitute." + fieldName + ")");
       injectMethodBuilder.addStatement(
         "$T.e(\"" + Consts.TAG + "\", \"The field '" + fieldName + "' is null, in class '\" + $T.class.getName() + \"!\")", AndroidLog, ClassName.get(parent));
       injectMethodBuilder.endControlFlow();
      }
     }
    }
    // 往類中添加inject() 函數(shù)
    helper.addMethod(injectMethodBuilder.build());

    // 寫入文件
    JavaFile.builder(packageName, helper.build()).build().writeTo(mFiler);

   }

   logger.info(">>> Autowired processor stop. <<<");
  }
 }

AutowiredProcessor生成的java文件舉例如下：

public class Test1Activity$$ARouter$$Autowired implements ISyringe {
 private SerializationService serializationService;

 @Override
 public void inject(Object target) {
 serializationService = ARouter.getInstance().navigation(SerializationService.class);;
 Test1Activity substitute = (Test1Activity)target;
 substitute.name = substitute.getIntent().getStringExtra("name");
 substitute.age = substitute.getIntent().getIntExtra("age", 0);
 substitute.girl = substitute.getIntent().getBooleanExtra("boy", false);
 substitute.pac = substitute.getIntent().getParcelableExtra("pac");
 if (null != serializationService) {
  substitute.obj = serializationService.json2Object(substitute.getIntent().getStringExtra("obj"), TestObj.class);
 } else {
  Log.e("ARouter::", "You want automatic inject the field 'obj' in class 'Test1Activity' , then you should implement 'SerializationService' to support object auto inject!");
 }
 substitute.url = substitute.getIntent().getStringExtra("url");
 substitute.helloService = ARouter.getInstance().navigation(HelloService.class);
 }
}

總結(jié)

至此，ARouter之Compiler SDK中的三種注解處理器都分析完畢！

接下來的文章開始分析API SDK的源碼！以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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