org.apache.dubbo.common.extension

注释类型 Activate

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

Activate. This annotation is useful for automatically activate certain extensions with the given criteria, for examples: @Activate can be used to load certain Filter extension when there are multiple implementations.

1. group() specifies group criteria. Framework SPI defines the valid group values.
2. value() specifies parameter key in URL criteria.

SPI provider can call ExtensionLoader.getActivateExtension(URL, String, String) to find out all activated extensions with the given criteria.

另请参阅:

SPI, URL, ExtensionLoader

可选元素概要

可选元素

限定符和类型	可选元素和说明
String[]	after 已过时。
String[]	before 已过时。
String[]	group Activate the current extension when one of the groups matches.
int	order Absolute ordering info, optional
String[]	value Activate the current extension when the specified keys appear in the URL's parameters.

元素详细资料

group

public abstract String[] group

Activate the current extension when one of the groups matches. The group passed into ExtensionLoader.getActivateExtension(URL, String, String) will be used for matching.

返回:

group names to match

另请参阅:

ExtensionLoader.getActivateExtension(URL, String, String)

默认值:

{}

value

public abstract String[] value

Activate the current extension when the specified keys appear in the URL's parameters.

For example, given @Activate("cache, validation"), the current extension will be return only when there's either cache or validation key appeared in the URL's parameters.

返回:

URL parameter keys

另请参阅:

ExtensionLoader.getActivateExtension(URL, String), ExtensionLoader.getActivateExtension(URL, String, String)

默认值:

{}

before

@Deprecated
public abstract String[] before

已过时。

Relative ordering info, optional Deprecated since 2.7.0

返回:

extension list which should be put before the current one

默认值:

{}

after

@Deprecated
public abstract String[] after

已过时。

Relative ordering info, optional Deprecated since 2.7.0

返回:

extension list which should be put after the current one

默认值:

{}

order

public abstract int order

Absolute ordering info, optional

返回:

absolute ordering info

默认值:

0