Package com.google.apphosting.runtime

Class BackgroundRequestCoordinator

java.lang.Object

com.google.apphosting.runtime.BackgroundRequestCoordinator

public class BackgroundRequestCoordinator
extends Object

BackgroundRequestCoordinator facilitates the exchange of two pieces of data between the background ThreadFactory and the JavaRuntime code that processes the fake request.

Background threads are backed by a "fake" request, which is initiated using the System API. The System API will return a request identifier and also initiate a "fake" request with this identifier stored in a header. The runtime must match each fake request up with the original API call and pass the user's Runnable to the thread so it can be executed, and pass the Thread back to the user's code so it can be joined and referenced.

Unfortunately there is a race between these two threads. We don't know whether the System API RPC will return first or whether the background request will be received first.

Constructor Summary

Constructors

Constructor	Description
BackgroundRequestCoordinator()

Method Summary

Modifier and Type	Method	Description
Thread	waitForThreadStart(String requestId, Runnable runnable, long deadlineInMillis)	Wait for the fake request with the specified requestId to call waitForUserRunnable(java.lang.String, java.lang.Thread, long) and then exchange runnable for the specified Thread.
Runnable	waitForUserRunnable(String requestId, Thread thread, long deadLineInMillis)	Wait for the system API call with the specified requestId to call waitForThreadStart(java.lang.String, java.lang.Runnable, long) and then exchange thread for the specified Runnable.

Methods inherited from class java.lang.Object

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

Constructor Detail

BackgroundRequestCoordinator

public BackgroundRequestCoordinator()

Method Detail

waitForThreadStart

public Thread waitForThreadStart(String requestId,
                                 Runnable runnable,
                                 long deadlineInMillis)
                          throws InterruptedException,
                                 TimeoutException

Wait for the fake request with the specified requestId to call waitForUserRunnable(java.lang.String, java.lang.Thread, long) and then exchange runnable for the specified Thread.

Throws:

InterruptedException

TimeoutException

waitForUserRunnable

public Runnable waitForUserRunnable(String requestId,
                                    Thread thread,
                                    long deadLineInMillis)
                             throws InterruptedException,
                                    TimeoutException

Wait for the system API call with the specified requestId to call waitForThreadStart(java.lang.String, java.lang.Runnable, long) and then exchange thread for the specified Runnable.

Throws:

InterruptedException

TimeoutException