com.alibaba.csp.sentinel.context

Class ContextUtil

java.lang.Object

com.alibaba.csp.sentinel.context.ContextUtil

public class ContextUtil
extends Object

Utility class to get or create Context in current thread.

Each SphU#entry() or SphO#entry() should be in a Context. If we don't invoke ContextUtil#enter() explicitly, DEFAULT context will be used.

Author:

jialiang.linjl, leyou(lihao), Eric Zhao

Constructor Summary

Constructors

Constructor and Description
ContextUtil()

Method Summary

Modifier and Type	Method and Description
static Context	enter(String name) Enter the invocation context.
static Context	enter(String name, String origin) Enter the invocation context.
static void	exit() Exit context of current thread, that is removing Context in the ThreadLocal.
static Context	getContext() Get Context of current thread.
protected static Context	trueEnter(String name, String origin)

Methods inherited from class java.lang.Object

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

Constructor Detail

ContextUtil

public ContextUtil()

Method Detail

enter

public static Context enter(String name,
                            String origin)

Enter the invocation context. The context is ThreadLocal, meaning that each thread has it's own Context. New context will be created if current thread doesn't have one.

A context will be related to a EntranceNode, which represents the entrance of the invocation tree. New EntranceNode will be created if current context does't have one. Note that same context name will share same EntranceNode globally.

Note that each distinct origin of name will lead to creating a new Node, meaning that total Node created will be of:
distinct context name count * distinct origin count
So when origin is too many, memory efficiency should be carefully considered.

Same resource in different context will count separately, see NodeSelectorSlot.

Parameters:

name - the context name.

origin - the origin of this invocation, usually the origin could be the Service Consumer's app name. The origin is useful when we want to control different invoker/consumer separately.

Returns:

The invocation context of the current thread.

trueEnter

protected static Context trueEnter(String name,
                                   String origin)

enter

public static Context enter(String name)

Enter the invocation context. The context is ThreadLocal, meaning that each thread has it's own Context. New context will be created if current thread doesn't have one.

A context will related to A EntranceNode, which is the entrance of the invocation tree. New EntranceNode will be created if current context does't have one. Note that same resource name will share same EntranceNode globally.

Same resource in different context will count separately, see NodeSelectorSlot.

Parameters:

name - the context name.

Returns:

The invocation context of the current thread.

exit

public static void exit()

Exit context of current thread, that is removing Context in the ThreadLocal.

getContext

public static Context getContext()

Get Context of current thread.

Returns:

context of current thread. Null value will be return if current thread does't have context.