com.alibaba.csp.sentinel.spi

Class SpiLoader<S>

java.lang.Object

com.alibaba.csp.sentinel.spi.SpiLoader<S>

public final class SpiLoader<S>
extends Object

A simple SPI loading facility (refactored since 1.8.1).

SPI is short for Service Provider Interface.

Service is represented by a single type, that is, a single interface or an abstract class. Provider is implementations of Service, that is, some classes which implement the interface or extends the abstract class.

For Service type: Must interface or abstract class.

For Provider class: Must have a zero-argument constructor so that they can be instantiated during loading.

For Provider configuration file: 1. The file contains a list of fully-qualified binary names of concrete provider classes, one per line. 2. Space and tab characters surrounding each name, as well as blank lines, are ignored. 3. The comment line character is #, all characters following it are ignored.

SpiLoader provide common functions, such as:

• Load all Provider instance unsorted/sorted list.
• Load highest/lowest order priority instance.
• Load first-found or default instance.
• Load instance by alias name or provider class.

Since:

1.4.0

Author:

Eric Zhao, cdfive

See Also:

Spi, ServiceLoader

Method Summary

Modifier and Type	Method and Description
void	load() Load the Provider class from Provider configuration file
S	loadDefaultInstance() Load default Provider instance Provider class with @Spi(isDefault = true)
S	loadFirstInstance() Load the first-found Provider instance
S	loadFirstInstanceOrDefault() Load the first-found Provider instance,if not found, return default Provider instance
S	loadHighestPriorityInstance() Load highest order priority instance, order value is defined in class's Spi annotation
S	loadInstance(Class<? extends S> clazz) Load instance by specific class type
S	loadInstance(String aliasName) Load instance by aliasName of Provider class
List<S>	loadInstanceList() Load all Provider instances of the specified Service
List<S>	loadInstanceListSorted() Load all Provider instances of the specified Service, sorted by order value in class's Spi annotation
S	loadLowestPriorityInstance() Load lowest order priority instance, order value is defined in class's Spi annotation
static <T> SpiLoader<T>	of(Class<T> service) Create SpiLoader instance via Service class Cached by className, and load from cache first
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

of

public static <T> SpiLoader<T> of(Class<T> service)

Create SpiLoader instance via Service class Cached by className, and load from cache first

Type Parameters:

T - Service type

Parameters:

service - Service class

Returns:

SpiLoader instance

loadInstanceList

public List<S> loadInstanceList()

Load all Provider instances of the specified Service

Returns:

Provider instances list

loadInstanceListSorted

public List<S> loadInstanceListSorted()

Load all Provider instances of the specified Service, sorted by order value in class's Spi annotation

Returns:

Sorted Provider instances list

loadHighestPriorityInstance

public S loadHighestPriorityInstance()

Load highest order priority instance, order value is defined in class's Spi annotation

Returns:

Provider instance of highest order priority

loadLowestPriorityInstance

public S loadLowestPriorityInstance()

Load lowest order priority instance, order value is defined in class's Spi annotation

Returns:

Provider instance of lowest order priority

loadFirstInstance

public S loadFirstInstance()

Load the first-found Provider instance

Returns:

Provider instance of first-found specific

loadFirstInstanceOrDefault

public S loadFirstInstanceOrDefault()

Load the first-found Provider instance,if not found, return default Provider instance

Returns:

Provider instance

loadDefaultInstance

public S loadDefaultInstance()

Load default Provider instance Provider class with @Spi(isDefault = true)

Returns:

default Provider instance

loadInstance

public S loadInstance(Class<? extends S> clazz)

Load instance by specific class type

Parameters:

clazz - class type

Returns:

Provider instance

loadInstance

public S loadInstance(String aliasName)

Load instance by aliasName of Provider class

Parameters:

aliasName - aliasName of Provider class

Returns:

Provider instance

load

public void load()

Load the Provider class from Provider configuration file

toString

public String toString()

Overrides:

toString in class Object