程序包 org.apache.dubbo.common.extension

注释类型 SPI

@Documented
@Retention(RUNTIME)
@Target(TYPE)
public @interface SPI

Marker for extension interface

Changes on extension configuration file
Use Protocol as an example, its configuration file 'META-INF/dubbo/com.xxx.Protocol' is changed from:

     com.foo.XxxProtocol
     com.foo.YyyProtocol
 

to key-value pair

     xxx=com.foo.XxxProtocol
     yyy=com.foo.YyyProtocol
 

The reason for this change is:

If there's third party library referenced by static field or by method in extension implementation, its class will fail to initialize if the third party library doesn't exist. In this case, dubbo cannot figure out extension's id therefore cannot be able to map the exception information with the extension, if the previous format is used.

For example:

Fails to load Extension("mina"). When user configure to use mina, dubbo will complain the extension cannot be loaded, instead of reporting which extract extension implementation fails and the extract reason.

可选元素概要

可选元素

修饰符和类型	可选元素	说明
ExtensionScope	scope	scope of SPI, default value is application scope.
String	value	default extension name

元素详细资料

value

String value

default extension name

默认值:

""

scope

ExtensionScope scope

scope of SPI, default value is application scope.

默认值:

org.apache.dubbo.common.extension.ExtensionScope.APPLICATION