io.grpc

Class Context.CancellableContext

java.lang.Object

io.grpc.Context

io.grpc.Context.CancellableContext

Enclosing class:

Context

public static final class Context.CancellableContext
extends Context

A context which inherits cancellation from its parent but which can also be independently cancelled and which will propagate cancellation to its descendants. To avoid leaking memory, every CancellableContext must have a defined lifetime, after which it is guaranteed to be cancelled.

Nested Class Summary

Nested classes/interfaces inherited from class io.grpc.Context

Context.CancellableContext, Context.CancellationListener, Context.Key<T>, Context.Storage

Field Summary

Fields inherited from class io.grpc.Context

ROOT

Method Summary

Modifier and Type	Method and Description
Context	attach() Attach this context, thus enter a new scope within which this context is Context.current().
boolean	cancel(Throwable cause) Cancel this context and optionally provide a cause (can be null) for the cancellation.
Throwable	cancellationCause() If a context Context.isCancelled() then return the cause of the cancellation or null if context was cancelled without a cause.
void	detach(Context toAttach) Reverse an attach(), restoring the previous context and exiting the current scope.
void	detachAndCancel(Context toAttach, Throwable cause) Cancel this context and detach it as the current context.
Deadline	getDeadline() A context may have an associated Deadline at which it will be automatically cancelled.
boolean	isCancelled() Is this context cancelled.
boolean	isCurrent() Deprecated. This method violates some GRPC class encapsulation and should not be used. If you must know whether a Context is the current context, check whether it is the same object returned by Context.current().

Methods inherited from class io.grpc.Context

addListener, call, current, currentContextExecutor, fixedContextExecutor, fork, key, keyWithDefault, removeListener, run, withCancellation, withDeadline, withDeadlineAfter, withValue, withValues, withValues, withValues, wrap, wrap

Methods inherited from class java.lang.Object

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

Method Detail

attach

public Context attach()

Description copied from class: Context

Attach this context, thus enter a new scope within which this context is Context.current(). The previously current context is returned. It is allowed to attach contexts where Context.isCancelled() is true.

Instead of using attach() and Context.detach(Context) most use-cases are better served by using the Context.run(Runnable) or Context.call(java.util.concurrent.Callable) to execute work immediately within a context's scope. If work needs to be done in other threads it is recommended to use the 'wrap' methods or to use a propagating executor.

All calls to attach() should have a corresponding Context.detach(Context) within the same method:

 Context previous = someContext.attach();
 try {
   // Do work
 } finally {
   someContext.detach(previous);
 }

Overrides:

attach in class Context

detach

public void detach(Context toAttach)

Description copied from class: Context

Reverse an attach(), restoring the previous context and exiting the current scope.

This context should be the same context that was previously attached. The provided replacement should be what was returned by the same attach() call. If an attach() and a detach() meet above requirements, they match.

It is expected that between any pair of matching attach() and detach(), all attach()es and detach()es are called in matching pairs. If this method finds that this context is not current, either you or some code in-between are not detaching correctly, and a SEVERE message will be logged but the context to attach will still be bound. Never use Context.current().detach(), as this will compromise this error-detecting mechanism.

Overrides:

detach in class Context

isCurrent

@Deprecated
public boolean isCurrent()

Deprecated. This method violates some GRPC class encapsulation and should not be used. If you must know whether a Context is the current context, check whether it is the same object returned by Context.current().

Returns true if the Context is the current context.

cancel

public boolean cancel(Throwable cause)

Cancel this context and optionally provide a cause (can be null) for the cancellation. This will trigger notification of listeners.

Returns:

true if this context cancelled the context and notified listeners, false if the context was already cancelled.

detachAndCancel

public void detachAndCancel(Context toAttach,
                            Throwable cause)

Cancel this context and detach it as the current context.

Parameters:

toAttach - context to make current.

cause - of cancellation, can be null.

isCancelled

public boolean isCancelled()

Description copied from class: Context

Is this context cancelled.

Overrides:

isCancelled in class Context

cancellationCause

public Throwable cancellationCause()

Description copied from class: Context

If a context Context.isCancelled() then return the cause of the cancellation or null if context was cancelled without a cause. If the context is not yet cancelled will always return null.

The cancellation cause is provided for informational purposes only and implementations should generally assume that it has already been handled and logged properly.

Overrides:

cancellationCause in class Context

getDeadline

public Deadline getDeadline()

Description copied from class: Context

A context may have an associated Deadline at which it will be automatically cancelled.

Overrides:

getDeadline in class Context

Returns:

A Deadline or null if no deadline is set.