分析需要儲備以下知識點：
- Java註解知識
- Java反射知識
- javapoet庫(在註釋裡也有簡單分析)
- auto-service庫
下面分析的時候會把各位看官當做已經掌握了以上知識點哈！
ARouter包含3個核心模組
- arouter-annotation 註解的宣告和資訊儲存類的模組
- arouter-compiler 編譯期解析註解資訊並生成相應類以便進行注入的模組
- arouter-api 核心呼叫Api功能的模組
1.模組arouter-annotation分析
- 這個註解用於路由傳遞過來的物件自動進行注入值
- 這個攔截器註解主要是用來宣告和確定攔截器優先順序
- Route註解是用到最多的，用來宣告路由的路徑和分組（分組這塊後面會詳細講解，因為分組這塊用到懶載入的形式來提高效能）
總結：這個模組主要還是用來宣告註解的引數和compiler搭配使用這樣分開，讓結構更加清晰。
2.模組arouter-compiler分析
在這個模組中引用了一下兩個核心庫
compile 'com.google.auto.service:auto-service:1.0-rc2' //auto-service 主要用於註解 Processor，對其生成 META-INF 配置資訊。
compile 'com.squareup:javapoet:1.7.0' // Javapoet是square一個工具，提供了各種 API 讓你用各種姿勢去生成 Java 程式碼檔案，避免了徒手拼接字串的尷尬。複製程式碼AutowiredProcessor分析
package com.alibaba.android.arouter.compiler.processor;
import com.alibaba.android.arouter.compiler.utils.Consts;
import com.alibaba.android.arouter.compiler.utils.Logger;
import com.alibaba.android.arouter.compiler.utils.TypeUtils;
import com.alibaba.android.arouter.facade.annotation.Autowired;
import com.alibaba.android.arouter.facade.enums.TypeKind;
import com.google.auto.service.AutoService;
import com.squareup.javapoet.ClassName;
import com.squareup.javapoet.FieldSpec;
import com.squareup.javapoet.JavaFile;
import com.squareup.javapoet.MethodSpec;
import com.squareup.javapoet.ParameterSpec;
import com.squareup.javapoet.TypeName;
import com.squareup.javapoet.TypeSpec;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.commons.collections4.MapUtils;
import org.apache.commons.lang3.StringUtils;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.Filer;
import javax.annotation.processing.ProcessingEnvironment;
import javax.annotation.processing.Processor;
import javax.annotation.processing.RoundEnvironment;
import javax.annotation.processing.SupportedAnnotationTypes;
import javax.annotation.processing.SupportedOptions;
import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.Modifier;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.Elements;
import javax.lang.model.util.Types;
import static com.alibaba.android.arouter.compiler.utils.Consts.ANNOTATION_TYPE_AUTOWIRED;
import static com.alibaba.android.arouter.compiler.utils.Consts.ISYRINGE;
import static com.alibaba.android.arouter.compiler.utils.Consts.JSON_SERVICE;
import static com.alibaba.android.arouter.compiler.utils.Consts.KEY_MODULE_NAME;
import static com.alibaba.android.arouter.compiler.utils.Consts.METHOD_INJECT;
import static com.alibaba.android.arouter.compiler.utils.Consts.NAME_OF_AUTOWIRED;
import static com.alibaba.android.arouter.compiler.utils.Consts.WARNING_TIPS;
import static javax.lang.model.element.Modifier.PUBLIC;
/**
* Processor used to create autowired helper
*
* @author zhilong <a href="mailto:zhilong.lzl@alibaba-inc.com">Contact me.</a>
* @version 1.0
* @since 2017/2/20 下午5:56
*/
@AutoService(Processor.class)//用 @AutoService 來註解這個處理器，可以自動生成配置資訊。
@SupportedOptions(KEY_MODULE_NAME)
@SupportedSourceVersion(SourceVersion.RELEASE_7)
@SupportedAnnotationTypes({ANNOTATION_TYPE_AUTOWIRED})
public class AutowiredProcessor extends AbstractProcessor {
private Filer mFiler; //檔案相關的輔助類
private Logger logger;
private Types types; //型別相關的輔助類
private TypeUtils typeUtils;
private Elements elements; //元素相關的輔助類
private Map<TypeElement, List<Element>> parentAndChild = new HashMap<>(); // 包含註解欄位的Map集合 // Contain field need autowired and his super class.
private static final ClassName ARouterClass = ClassName.get("com.alibaba.android.arouter.launcher", "ARouter");
private static final ClassName AndroidLog = ClassName.get("android.util", "Log");
@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.
logger.info(">>> AutowiredProcessor init. <<<");
}
@Override
public boolean process(Set<? extends TypeElement> set, RoundEnvironment roundEnvironment) {
if (CollectionUtils.isNotEmpty(set)) {
try {
logger.info(">>> Found autowired field, start... <<<");
//傳入被Autowire註解修飾的集合並且執行分類填充進parentAndChild的Map集合
categories(roundEnvironment.getElementsAnnotatedWith(Autowired.class));
//執行解析
generateHelper();
} catch (Exception e) {
logger.error(e);
}
return true;
}
return false;
}
private void generateHelper() throws IOException, IllegalAccessException {
TypeElement type_ISyringe = elements.getTypeElement(ISYRINGE); //獲取注入物件的元素類
TypeElement type_JsonService = elements.getTypeElement(JSON_SERVICE);// 獲取JsonService元素類
TypeMirror iProvider = elements.getTypeElement(Consts.IPROVIDER).asType(); //獲取IProvider類物件
TypeMirror activityTm = elements.getTypeElement(Consts.ACTIVITY).asType(); //獲取activity類物件
TypeMirror fragmentTm = elements.getTypeElement(Consts.FRAGMENT).asType(); //獲取fragment類物件
TypeMirror fragmentTmV4 = elements.getTypeElement(Consts.FRAGMENT_V4).asType(); //獲取fragment的v4版本的類物件
// Build input param name.
ParameterSpec objectParamSpec = ParameterSpec.builder(TypeName.OBJECT, "target").build(); //生成方法的引數 ***(Object target)
if (MapUtils.isNotEmpty(parentAndChild)) { //解析parentAndChild
for (Map.Entry<TypeElement, List<Element>> entry : parentAndChild.entrySet()) { // 被autowire註解的迴圈物件
// Build method : 'inject'
MethodSpec.Builder injectMethodBuilder = MethodSpec.methodBuilder(METHOD_INJECT)
.addAnnotation(Override.class)
.addModifiers(PUBLIC)
.addParameter(objectParamSpec);
//生成方法injtct 所以和上面聯合在一塊就是生成了@override public void inject(Object target)
TypeElement parent = entry.getKey();
List<Element> childs = entry.getValue();
String qualifiedName = parent.getQualifiedName().toString();//整個類名
String packageName = qualifiedName.substring(0, qualifiedName.lastIndexOf("."));//擷取包名
String fileName = parent.getSimpleName() + NAME_OF_AUTOWIRED;//檔名
logger.info(">>> Start process " + childs.size() + " field in " + parent.getSimpleName() + " ... <<<");
// 生成類 類名是 **$$**$***實現ISyringe介面並且是public的類
TypeSpec.Builder helper = TypeSpec.classBuilder(fileName)
.addJavadoc(WARNING_TIPS)
.addSuperinterface(ClassName.get(type_ISyringe))
.addModifiers(PUBLIC);
// 生成一個私有的全域性物件serializationService
FieldSpec jsonServiceField = FieldSpec.builder(TypeName.get(type_JsonService.asType()), "serializationService", Modifier.PRIVATE).build();
helper.addField(jsonServiceField);
// 在方法體內加入指定的語句執行
injectMethodBuilder.addStatement("serializationService = $T.getInstance().navigation($T.class)", ARouterClass, ClassName.get(type_JsonService));
injectMethodBuilder.addStatement("$T substitute = ($T)target", ClassName.get(parent), ClassName.get(parent));
//生成方法體並且注入
// Generate method body, start inject.
for (Element element : childs) {
Autowired fieldConfig = element.getAnnotation(Autowired.class);
String fieldName = element.getSimpleName().toString();
if (types.isSubtype(element.asType(), iProvider)) { // It's provider //如果是iProvider的子類
if ("".equals(fieldConfig.name())) { // User has not set service path, then use byType.
//預設通過類解析
// Getter
injectMethodBuilder.addStatement(
"substitute." + fieldName + " = $T.getInstance().navigation($T.class)",
ARouterClass,
ClassName.get(element.asType())
);
} else { // use byName //如果指定了Autowired的name的話 則用name進行解析
// Getter
injectMethodBuilder.addStatement(
"substitute." + fieldName + " = ($T)$T.getInstance().build($S).navigation();",
ClassName.get(element.asType()),
ARouterClass,
fieldConfig.name()
);
}
// Validater 校驗
if (fieldConfig.required()) { //校驗此欄位是不是必填的不許為空
injectMethodBuilder.beginControlFlow("if (substitute." + fieldName + " == null)");
injectMethodBuilder.addStatement(
"throw new RuntimeException(\"The field '" + fieldName + "' is null, in class '\" + $T.class.getName() + \"!\")", ClassName.get(parent));
injectMethodBuilder.endControlFlow();
}
} else { // It's normal intent value 如果是普通的引數傳遞
String originalValue = "substitute." + fieldName;
String statement = "substitute." + fieldName + " = substitute.";
boolean isActivity = false;
if (types.isSubtype(parent.asType(), activityTm)) { // Activity, then use getIntent() 如果是activity則通過getIntent注入
isActivity = true;
statement += "getIntent().";
} else if (types.isSubtype(parent.asType(), fragmentTm) || types.isSubtype(parent.asType(), fragmentTmV4)) { // Fragment, then use getArguments() 如果是fragment則通過getArguements進行注入
statement += "getArguments().";
} else {//其他方式暫不支援
throw new IllegalAccessException("The field [" + fieldName + "] need autowired from intent, its parent must be activity or fragment!");
}
//判斷型別進行相應的轉換生成程式碼
statement = buildStatement(originalValue, statement, typeUtils.typeExchange(element), isActivity);
// 生成servicejson解析的服務迴圈解析生成程式碼
if (statement.startsWith("serializationService.")) { // Not mortals
injectMethodBuilder.beginControlFlow("if (null != serializationService)");
injectMethodBuilder.addStatement(
"substitute." + fieldName + " = " + statement,
(StringUtils.isEmpty(fieldConfig.name()) ? fieldName : fieldConfig.name()),
ClassName.get(element.asType())
);
injectMethodBuilder.nextControlFlow("else");
injectMethodBuilder.addStatement(
"$T.e(\"" + Consts.TAG + "\", \"You want automatic inject the field '" + fieldName + "' in class '$T' , then you should implement 'SerializationService' to support object auto inject!\")", AndroidLog, ClassName.get(parent));
injectMethodBuilder.endControlFlow();
} else {
//在方法體內加入程式碼
injectMethodBuilder.addStatement(statement, StringUtils.isEmpty(fieldConfig.name()) ? fieldName : fieldConfig.name());
}
// Validator 校驗支援解析的型別為空則做記錄
if (fieldConfig.required() && !element.asType().getKind().isPrimitive()) { // Primitive wont be check.
injectMethodBuilder.beginControlFlow("if (null == substitute." + fieldName + ")");
injectMethodBuilder.addStatement(
"$T.e(\"" + Consts.TAG + "\", \"The field '" + fieldName + "' is null, in class '\" + $T.class.getName() + \"!\")", AndroidLog, ClassName.get(parent));
injectMethodBuilder.endControlFlow();
}
}
}
// 生成指定方法
helper.addMethod(injectMethodBuilder.build());
// Generate autowire helper 生成檔案
JavaFile.builder(packageName, helper.build()).build().writeTo(mFiler);
logger.info(">>> " + parent.getSimpleName() + " has been processed, " + fileName + " has been generated. <<<");
}
logger.info(">>> Autowired processor stop. <<<");
}
}
private String buildStatement(String originalValue, String statement, int type, boolean isActivity) {
if (type == TypeKind.BOOLEAN.ordinal()) {
statement += (isActivity ? ("getBooleanExtra($S, " + originalValue + ")") : ("getBoolean($S)"));
} else if (type == TypeKind.BYTE.ordinal()) {
statement += (isActivity ? ("getByteExtra($S, " + originalValue + "") : ("getByte($S)"));
} else if (type == TypeKind.SHORT.ordinal()) {
statement += (isActivity ? ("getShortExtra($S, " + originalValue + ")") : ("getShort($S)"));
} else if (type == TypeKind.INT.ordinal()) {
statement += (isActivity ? ("getIntExtra($S, " + originalValue + ")") : ("getInt($S)"));
} else if (type == TypeKind.LONG.ordinal()) {
statement += (isActivity ? ("getLongExtra($S, " + originalValue + ")") : ("getLong($S)"));
} else if (type == TypeKind.CHAR.ordinal()) {
statement += (isActivity ? ("getCharExtra($S, " + originalValue + ")") : ("getChar($S)"));
} else if (type == TypeKind.FLOAT.ordinal()) {
statement += (isActivity ? ("getFloatExtra($S, " + originalValue + ")") : ("getFloat($S)"));
} else if (type == TypeKind.DOUBLE.ordinal()) {
statement += (isActivity ? ("getDoubleExtra($S, " + originalValue + ")") : ("getDouble($S)"));
} else if (type == TypeKind.STRING.ordinal()) {
statement += (isActivity ? ("getStringExtra($S)") : ("getString($S)"));
} else if (type == TypeKind.PARCELABLE.ordinal()) {
statement += (isActivity ? ("getParcelableExtra($S)") : ("getParcelable($S)"));
} else if (type == TypeKind.OBJECT.ordinal()) {
statement = "serializationService.parseObject(substitute." + (isActivity ? "getIntent()." : "getArguments().") + (isActivity ? "getStringExtra($S)" : "getString($S)") + ", new com.alibaba.android.arouter.facade.model.TypeWrapper<$T>(){}.getType())";
}
return statement;
}
/**
* Categories field, find his papa.
*
* @param elements Field need autowired
*/
private void categories(Set<? extends Element> elements) throws IllegalAccessException {
if (CollectionUtils.isNotEmpty(elements)) {//判斷註解集合是不是為空
for (Element element : elements) {//迴圈解析
TypeElement enclosingElement = (TypeElement) element.getEnclosingElement();// 獲取父元素
if (element.getModifiers().contains(Modifier.PRIVATE)) {// 檢驗是否註解的物件不能被private修飾
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 {//第1次進入會生成列表並且組裝到parentAndChild的map中
List<Element> childs = new ArrayList<>();
childs.add(element);
parentAndChild.put(enclosingElement, childs);
}
}
logger.info("categories finished.");
}
}
}複製程式碼都是通過解析Element物件的註解的引數來進行編寫相應的Java類
下圖就是上面AutowiredProcessor通過解析生成的類
下圖是攔截器的Processor類和上面一樣也會生成相應的攔截類具體的程式碼都很相似就不貼分析的程式碼啦
貼上攔截器註解後編譯器生成的類
在Route的Processor中驗證路徑的程式碼和上面是很類似的就不一一分析的需要注意點校驗和分類
總結：以上的類稍微瞭解就好，因為使用到的就是將註解解析自動生成響應的類方便Api核心去呼叫將整個框架聯動起來
3.模組arouter-api分析
在外部使用的時候呼叫的Api是ARouter，但是它是使用代理模式，實際上的操作是_ARouter類進行呼叫。
我們從init方法開始解析：
/**
* Init, it must be call before used router.
*/
public static void init(Application application) {
if (!hasInit) {
logger = _ARouter.logger; //需要初始化出_ARouter的日誌類 因為內部和外部都會呼叫所以一定要先調init
_ARouter.logger.info(Consts.TAG, "ARouter init start.");
hasInit = _ARouter.init(application);//真正的初始化ARouter核心 裡面呼叫了LogisticsCenter.init(mContext, executor);內部建立了一個執行緒池
if (hasInit) {
_ARouter.afterInit();//初始化完成之後開始處理攔截器
}
_ARouter.logger.info(Consts.TAG, "ARouter init over.");
}
}複製程式碼LogisticCenter的初始化核心就是講自定義生成的類進行呼叫loadInto然後快取近Warehouse倉庫中以便快速呼叫：
/**
* LogisticsCenter init, load all metas in memory. Demand initialization
*/
public synchronized static void init(Context context, ThreadPoolExecutor tpe) throws HandlerException {
mContext = context;
executor = tpe;
try {
long startInit = System.currentTimeMillis();
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 generate by arouter-compiler.
routerMap = ClassUtils.getFileNameByPackageName(mContext, ROUTE_ROOT_PAKCAGE);//搜尋routerMap
if (!routerMap.isEmpty()) {
context.getSharedPreferences(AROUTER_SP_CACHE_KEY, Context.MODE_PRIVATE).edit().putStringSet(AROUTER_SP_KEY_MAP, routerMap).apply();// 將搜尋到的map儲存到sp中
}
} 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) {//通過反射初始化自動生成的類並且進行呼叫loadInto方法將資料快取到Warehouse的倉庫中
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() + "]");
}
}複製程式碼在我們所有呼叫ARouter.getInstance().build(-).navigation()都會經來進行組裝Postcard和completion方法通知組裝完成，所以我們再來看一下postcard是個什麼鬼
看了一下就是繼承了RouteMeta並且多了一些引數，換句話說就是在View層可以多自定義一些動畫和引數傳遞的方式
那麼繼續看completion方法
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.
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 {
// 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()));
}
IRouteGroup iGroupInstance = groupMeta.getConstructor().newInstance(); //對路由的路徑進行分組
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); // Reload //分組完畢後進行重新載入 也就是會執行到下面else段
}
} else {
// 將所有手機到的目標資訊都取出來封裝進postcard
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());
}
/**
* 如果是Iprovider服務類和fragment則跳過所有攔截器
*/
switch (routeMeta.getType()) {
case PROVIDER: // if the route is provider, should find its instance
// Its provider, so it must be implememt 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;
}
}
}複製程式碼核心的封裝流程講完了我們們開始看路由的跳轉和攔截:
@Override
public void doInterceptions(final Postcard postcard, final InterceptorCallback callback) {
if (null != Warehouse.interceptors && Warehouse.interceptors.size() > 0) {
checkInterceptorsInitStatus();
if (!interceptorHasInit) {
callback.onInterrupt(new HandlerException("Interceptors initialization takes too much time."));
return;
}
LogisticsCenter.executor.execute(new Runnable() {
@Override
public void run() { //使用執行緒池並且利用CountDownLatch來處理執行緒同步問題進行一個個攔截器的蘭姐
CancelableCountDownLatch interceptorCounter = new CancelableCountDownLatch(Warehouse.interceptors.size());
try {
_excute(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(new HandlerException(postcard.getTag().toString()));
} else {
callback.onContinue(postcard);
}
} catch (Exception e) {
callback.onInterrupt(e);
}
}
});
} else {
callback.onContinue(postcard);
}
}
/**
* Excute interceptor
*
* @param index current interceptor index
* @param counter interceptor counter
* @param postcard routeMeta
*/
private static void _excute(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();
// 回撥自身將所有攔截器執行一邊
_excute(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 excute over with fatal exception.
postcard.setTag(null == exception ? new HandlerException("No message.") : exception.getMessage()); // save the exception message for backup.
//如果已經被攔截則取消同步狀態
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());
// }
}
});
}
}複製程式碼看到以上程式碼知道他們是利用執行緒池加上CountLatchDown的方式來進行執行緒空值同步並且呼叫_excute進行回撥來一步步拿出攔截器來呼叫
/**
* 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) {
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) { //這裡就是回撥有沒有找到路由的回撥
callback.onLost(postcard);
} else { // No callback for this invoke, then we use the global degrade service. //沒有找到路由則進行降級服務的呼叫
DegradeService degradeService = ARouter.getInstance().navigation(DegradeService.class);
if (null != degradeService) {
degradeService.onLost(context, postcard);
}
}
return null;
}
if (null != callback) { // 找到路由的回撥
callback.onFound(postcard);
}
if (!postcard.isGreenChannel()) { // It must be run in async thread, maybe interceptor cost too mush time made ANR. //判斷當前呼叫是不是走『綠色通道』跳過所有攔截器
//一定要呼叫一下兩個方式之一才能繼續執行路徑否則返回為空
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); //這個方法就是下圖所執行的返回分類物件
}
return null;
}複製程式碼到這裡核心的流程基本全部講完了，因此可以看到攔截都是進行全域性的攔截，但是他們通過註解的extra值進行處理來分類攔截的過程通過優先順序排序攔截。更多的細節大家可以下載原始碼仔細研究，希望本文對大家有幫助，如有錯誤之處，涵請指出，多多指教，感激不盡。