com.alibaba.dubbo.common.extension

Annotation Type Adaptive

@Documented
@Retention(value=RUNTIME)
@Target(value={TYPE,METHOD})
public @interface Adaptive

Provide helpful information for ExtensionLoader to inject dependency extension instance.

See Also:

ExtensionLoader, URL

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String[]	value Decide which target extension to be injected.

Element Detail

value

public abstract String[] value

Decide which target extension to be injected. The name of the target extension is decided by the parameter passed in the URL, and the parameter names are given by this method.

If the specified parameters are not found from URL, then the default extension will be used for dependency injection (specified in its interface's SPI).

For examples, given String[] {"key1", "key2"}:

1. find parameter 'key1' in URL, use its value as the extension's name
2. try 'key2' for extension's name if 'key1' is not found (or its value is empty) in URL
3. use default extension if 'key2' doesn't appear either
4. otherwise, throw IllegalStateException

If default extension's name is not give on interface's SPI, then a name is generated from interface's class name with the rule: divide classname from capital char into several parts, and separate the parts with dot '.', for example: for com.alibaba.dubbo.xxx.YyyInvokerWrapper, its default name is String[] {"yyy.invoker.wrapper"}. This name will be used to search for parameter from URL.

Returns:

parameter key names in URL

Default:

{}