Class Storage

api/src/context/java/io/grpc/Context.java:1001–1039

Defines the mechanisms for attaching and detaching the "current" context. The constructor for extending classes must not trigger any activity that can use Context, which includes logging, otherwise it can trigger an infinite initialization loop. Extending classes must not assume that only o

   * subject to change.
   */
  public abstract static class Storage {
    /**
     * Implements {@link io.grpc.Context#attach}.
     *
     * <p>Caution: {@link Context#attach()} interprets a return value of {@code null} to mean
     * the same thing as {@link Context#ROOT}.
     *
     * <p>See also: {@link #current()}.

     * @param toAttach the context to be attached
     * @return A {@link Context} that should be passed back into {@link #detach(Context, Context)}
     *        as the {@code toRestore} parameter. {@code null} is a valid return value, but see
     *        caution note.
     */
    public abstract Context doAttach(Context toAttach);

    /**
     * Implements {@link io.grpc.Context#detach}.
     *
     * @param toDetach the context to be detached. Should be, or be equivalent to, the current
     *        context of the current scope
     * @param toRestore the context to be the current.  Should be, or be equivalent to, the context
     *        of the outer scope
     */
    public abstract void detach(Context toDetach, Context toRestore);

    /**
     * Implements {@link io.grpc.Context#current}.
     *
     * <p>Caution: {@link Context} interprets a return value of {@code null} to mean the same
     * thing as {@link Context#ROOT}.
     *
     * <p>See also {@link #doAttach(Context)}.
     *
     * @return The context of the current scope. {@code null} is a valid return value, but see
     *        caution note.
     */
    public abstract Context current();
  }

  /**
   * Stores listener and executor pair.