DUBBO 源码分析(1):SPI与自适应拓展点

.java

.class

cachedWrapperClasses;

cachedAdaptiveClass;

instance

缓存

className1

wrap

DUBBO 源码分析: SPI 与自适应拓展

className3

ExtensionLoader2

cachedInstances;

EXTENSION_INSTANCES;

javassist/JDK

...

N

getExtension();

dubbo

ExtensionLoaderN

ExtensionLoader

ExtensionLoader<T> getExtensionLoader(Class<T> type);

generate

dubbo internal

getAdaptiveExtension();

createAdaptiveExtensionClass()

injection

private T createExtension(String name);

init: cachedAdaptiveInstance

adaptive extension: 1) class和 instance 都唯一; 2) @Adaptive method 可能有多个.span style=\"font-size: inherit;\

createAdaptiveExtension()

newInstance()

className2

createExtension(name)

创建AdaptiveExtension

Classin JVM

load 

spi

创建 Extension

getExtensionClass(String name)  ->getExtensionClasses()    ->loadExtensionClasses()

is

init: cachedAdaptiveClass

EXTENSION_LOADERS;

cachedAdaptiveInstance;

init: cachedWrapperClasses;cachedAdaptiveClass;cachedClasses;

ExtensionLoader3

方法调用由下面的instance执行; 具体哪个 instance 通过 url 指定

ExtensionLoader1

cachedClasses;

String createAdaptiveExtensionClass();1. adaptiveExtension类代码生成; 2. 查找classLoader;3. 查找 compiler; 4. 利用2)的 classLoader和3)的 compiler对步骤1)里的代码进行编译和加载; 

service directory

classLoader

loop cachedWrapperClasses

源码版本: 2.6.7-release. 参考文档: http://dubbo.apache.org/zh-cn/docs/source_code_guide/adaptive-extension.html