io.opencensus.contrib.agent.bootstrap

Class ContextTrampoline

java.lang.Object

io.opencensus.contrib.agent.bootstrap.ContextTrampoline

public final class ContextTrampoline
extends Object

ContextTrampoline provides methods for accessing and manipulating the context from instrumented bytecode.

ContextTrampoline avoids tight coupling with the concrete implementation of the context by accessing and manipulating the context through the ContextStrategy interface.

Both ContextTrampoline and ContextStrategy are loaded by the bootstrap classloader so that they can be used from classes loaded by the bootstrap classloader. A concrete implementation of ContextStrategy will be loaded by the system classloader. This allows for using the same context implementation as the instrumented application.

ContextTrampoline is implemented as a static class to allow for easy and fast use from instrumented bytecode. We cannot use dependency injection for the instrumented bytecode.

Since:

0.9

Method Summary

Modifier and Type	Method and Description
static void	attachContextForThread(Thread thread) Attaches the context that was previously saved for the specified thread.
static void	saveContextForThread(Thread thread) Saves the context that is associated with the current scope.
static void	setContextStrategy(ContextStrategy contextStrategy) Sets the concrete strategy for accessing and manipulating the context.
static Runnable	wrapInCurrentContext(Runnable runnable) Wraps a Runnable so that it executes with the context that is associated with the current scope.

Methods inherited from class java.lang.Object

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

Method Detail

setContextStrategy

public static void setContextStrategy(ContextStrategy contextStrategy)

Sets the concrete strategy for accessing and manipulating the context.

NB: The agent is responsible for setting the context strategy once before any other method of this class is called.

Parameters:

contextStrategy - the concrete strategy for accessing and manipulating the context

Since:

0.9

wrapInCurrentContext

public static Runnable wrapInCurrentContext(Runnable runnable)

Wraps a Runnable so that it executes with the context that is associated with the current scope.

Parameters:

runnable - a Runnable object

Returns:

the wrapped Runnable object

Since:

0.9

See Also:

ContextStrategy.wrapInCurrentContext(java.lang.Runnable)

saveContextForThread

public static void saveContextForThread(Thread thread)

Saves the context that is associated with the current scope.

The context will be attached when entering the specified thread's Thread.run() method.

Parameters:

thread - a Thread object

Since:

0.9

attachContextForThread

public static void attachContextForThread(Thread thread)

Attaches the context that was previously saved for the specified thread.

Parameters:

thread - a Thread object

Since:

0.9