brown.tracingplane.impl

Class ThreadLocalTransitLayer

java.lang.Object

brown.tracingplane.impl.ThreadLocalTransitLayer

All Implemented Interfaces:

TransitLayer

public class ThreadLocalTransitLayer
extends java.lang.Object
implements TransitLayer

A straightforward TransitLayer implementation based on thread-local storage. This is the out-of-the-box transit layer implementation provided by the Tracing Plane.

It is unlikely that you will need to manually configure the Tracing Plane to use this class -- depending on the distribution you are using, it is likely to be configured by default.

Otherwise, to manually configure the ThreadLocalTransitLayer, you must configure it using the baggage.transit property to use ThreadLocalTransitLayerFactory, e.g.:

      -Dbaggage.transit=brown.tracingplane.impl.ThreadLocalTransitLayerFactory
 

It can alternatively be configured in your typesafe config's application.conf, e.g.:

 baggage.transit = "brown.tracingplane.impl.ThreadLocalTransitLayerFactory"
 

Constructor Summary

Constructors

Constructor and Description
ThreadLocalTransitLayer(BaggageProvider<BaggageContext> provider)

Method Summary

Modifier and Type	Method and Description
BaggageContext	branch() Create and return a branched copy of the currently active baggage context.
byte[]	branchBytes() Create and return a branched, serialized copy of the currently active baggage context.
void	discard() Discard the currently active BaggageContext.
void	join(BaggageContext otherContext) Merges the contents of otherContext into the currently active context.
void	join(byte[] serialized, int offset, int length) Deserializes the provided context and merges it into the currently active context.
void	join(java.nio.ByteBuffer serializedContext) Deserializes the provided context and merges it into the currently active context.
BaggageContext	peek() Gets the currently active BaggageContext.
void	set(BaggageContext baggage) Discards the currently active BaggageContext, then activates the provided baggage.
void	set(byte[] serialized, int offset, int length) Deserializes the provided context and merges it into the currently active context.
void	set(java.nio.ByteBuffer serializedContext) Deserializes the provided context, discards any currently active context, and replaces it with the deserialized context.
BaggageContext	take() Gets and removes the currently active BaggageContext.
byte[]	takeBytes() Gets, removes, and serializes the currently active BaggageContext.
void	update(BaggageContext baggage) Sets the currently active BaggageContext.

Methods inherited from class java.lang.Object

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

Constructor Detail

ThreadLocalTransitLayer

public ThreadLocalTransitLayer(BaggageProvider<BaggageContext> provider)

Parameters:

provider - the implementation of BaggageProvider in use by this transit layer

Method Detail

discard

public void discard()

Description copied from interface: TransitLayer

Discard the currently active BaggageContext.

Specified by:

discard in interface TransitLayer

branch

public BaggageContext branch()

Description copied from interface: TransitLayer

Create and return a branched copy of the currently active baggage context. Typically, this will just duplicate the active context or increment a reference count. Sometimes it will create a new instance, or even modify the contents of the branched context.

Specified by:

branch in interface TransitLayer

Returns:

a baggage instance branched from the currently active context, possibly null

branchBytes

public byte[] branchBytes()

Description copied from interface: TransitLayer

Create and return a branched, serialized copy of the currently active baggage context. Typically, this will just duplicate the active context or increment a reference count. Sometimes it will create a new instance, or even modify the contents of the branched context.

Specified by:

branchBytes in interface TransitLayer

Returns:

a baggage instance branched from the currently active context and serialized, possibly null

join

public void join(BaggageContext otherContext)

Description copied from interface: TransitLayer

Merges the contents of otherContext into the currently active context. otherContext should not be reused after calling this method, and should be treated as discarded.

Specified by:

join in interface TransitLayer

Parameters:

otherContext - another baggage context, possibly null

join

public void join(java.nio.ByteBuffer serializedContext)

Description copied from interface: TransitLayer

Deserializes the provided context and merges it into the currently active context.

Specified by:

join in interface TransitLayer

Parameters:

serializedContext - a serialized baggage context, possibly null

join

public void join(byte[] serialized,
                 int offset,
                 int length)

Description copied from interface: TransitLayer

Deserializes the provided context and merges it into the currently active context.

Specified by:

join in interface TransitLayer

set

public void set(BaggageContext baggage)

Description copied from interface: TransitLayer

Discards the currently active BaggageContext, then activates the provided baggage. If baggage is just a modified version of the currently active BaggageContext, then it is better to use the TransitLayer.update(BaggageContext) method instead.

Specified by:

set in interface TransitLayer

Parameters:

baggage - The new baggage context to activate.

set

public void set(java.nio.ByteBuffer serializedContext)

Description copied from interface: TransitLayer

Deserializes the provided context, discards any currently active context, and replaces it with the deserialized context.

Specified by:

set in interface TransitLayer

Parameters:

serializedContext - a serialized baggage context, possibly null

set

public void set(byte[] serialized,
                int offset,
                int length)

Description copied from interface: TransitLayer

Deserializes the provided context and merges it into the currently active context.

Specified by:

set in interface TransitLayer

Parameters:

serialized - a serialized baggage context, possibly null

offset - offset into the byte array

length - length of serialized bytes

take

public BaggageContext take()

Description copied from interface: TransitLayer

Gets and removes the currently active BaggageContext. After calling this method, there will be no active BaggageContext.

Specified by:

take in interface TransitLayer

Returns:

the current BaggageContext.

takeBytes

public byte[] takeBytes()

Description copied from interface: TransitLayer

Gets, removes, and serializes the currently active BaggageContext. After calling this method, there will be no active BaggageContext.

Specified by:

takeBytes in interface TransitLayer

Returns:

the current BaggageContext.

peek

public BaggageContext peek()

Description copied from interface: TransitLayer

Gets the currently active BaggageContext. The BaggageContext instance remains active after calling this method. Use TransitLayer.take() to if you wish to get and remove the currently active context.

Specified by:

peek in interface TransitLayer

Returns:

the active BaggageContext

update

public void update(BaggageContext baggage)

Description copied from interface: TransitLayer

Sets the currently active BaggageContext. A call to this method implies that the provided context argument is an updated version of the active context. Conversely, if you intend to replace the currently active context (e.g., because a different execution is beginning), use the TransitLayer.set(BaggageContext) method.

Specified by:

update in interface TransitLayer