ThreadLocalCurrentTraceContext (Brave 5.13.9 API)

java.lang.Object
- brave.propagation.CurrentTraceContext
- - brave.propagation.ThreadLocalCurrentTraceContext

Direct Known Subclasses:

CurrentTraceContext.Default
```
public class ThreadLocalCurrentTraceContext
extends CurrentTraceContext
```
In-process trace context propagation backed by a static thread local.
Design notes

A static thread local ensures we have one context per thread, as opposed to one per thread- tracer. This means all tracer instances will be able to see any tracer's contexts.
The trade-off of this (instance-based reference) vs the reverse: trace contexts are not separated by tracer by default. For example, to make a trace invisible to another tracer, you have to use a non-default implementation.
Sometimes people make different instances of the tracer just to change configuration like the local service name. If we used a thread-instance approach, none of these would be able to see eachother's scopes. This would break Tracing.currentTracer() scope visibility in a way few would want to debug. It might be phrased as "MySQL always starts a new trace and I don't know why."
If you want a different behavior, use a different subtype of CurrentTraceContext, possibly your own, or raise an issue and explain what your use case is.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class ThreadLocalCurrentTraceContext.Builder
- Nested classes/interfaces inherited from class brave.propagation.CurrentTraceContext
  CurrentTraceContext.Default, CurrentTraceContext.Scope, CurrentTraceContext.ScopeDecorator

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`clear()`	This component is backed by a possibly static shared thread local.
`static CurrentTraceContext`	`create()`
`TraceContext`	`get()`	Returns the current span in scope or null if there isn't one.
`static ThreadLocalCurrentTraceContext.Builder`	`newBuilder()`
`CurrentTraceContext.Scope`	`newScope(TraceContext currentSpan)`	Sets the current span in scope until the returned object is closed.

Methods inherited from class brave.propagation.CurrentTraceContext
decorateScope, executor, executorService, maybeScope, wrap, wrap

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - create
```
public static CurrentTraceContext create()
```
  - newBuilder
```
public static ThreadLocalCurrentTraceContext.Builder newBuilder()
```
  - clear
```
public void clear()
```
    This component is backed by a possibly static shared thread local. Call this to clear the reference when you are sure any residual state is due to a leak. This is generally only useful in tests.
    
    Since:
    
    5.11
  - get
```
public TraceContext get()
```
    Description copied from class: CurrentTraceContext
    
    Returns the current span in scope or null if there isn't one.
    
    Specified by:
    
    get in class CurrentTraceContext
  - newScope
```
public CurrentTraceContext.Scope newScope(@Nullable
                                          TraceContext currentSpan)
```
    Description copied from class: CurrentTraceContext
    
    Sets the current span in scope until the returned object is closed. It is a programming error to drop or never close the result. Using try-with-resources is preferred for this reason.
    
    Specified by:
    
    newScope in class CurrentTraceContext
    
    Parameters:
    
    currentSpan - span to place into scope or null to clear the scope