Package io.grpc.servlet.jakarta

Class AsyncServletOutputStreamWriter

java.lang.Object

io.grpc.servlet.jakarta.AsyncServletOutputStreamWriter

final class AsyncServletOutputStreamWriter
extends java.lang.Object

Handles write actions from the container thread and the application thread.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static interface	AsyncServletOutputStreamWriter.ActionItem	Write actions, e.g.
(package private) static interface	AsyncServletOutputStreamWriter.Log
private static class	AsyncServletOutputStreamWriter.WriteState

Field Summary

Fields

Modifier and Type	Field	Description
private AsyncServletOutputStreamWriter.ActionItem	completeAction
private AsyncServletOutputStreamWriter.ActionItem	flushAction
private java.util.function.BooleanSupplier	isReady
private AsyncServletOutputStreamWriter.Log	log
private java.lang.Thread	parkingThread
private java.util.function.BiFunction<byte[],java.lang.Integer,AsyncServletOutputStreamWriter.ActionItem>	writeAction
private java.util.Queue<AsyncServletOutputStreamWriter.ActionItem>	writeChain	New write actions will be buffered into this queue if the servlet output stream is not ready or the queue is not drained.
private java.util.concurrent.atomic.AtomicReference<AsyncServletOutputStreamWriter.WriteState>	writeState	Memory boundary for write actions.

Constructor Summary

Constructors

Constructor	Description
AsyncServletOutputStreamWriter(jakarta.servlet.AsyncContext asyncContext, ServletServerStream.ServletTransportState transportState, InternalLogId logId)
AsyncServletOutputStreamWriter(java.util.function.BiFunction<byte[],java.lang.Integer,AsyncServletOutputStreamWriter.ActionItem> writeAction, AsyncServletOutputStreamWriter.ActionItem flushAction, AsyncServletOutputStreamWriter.ActionItem completeAction, java.util.function.BooleanSupplier isReady, AsyncServletOutputStreamWriter.Log log)	Constructor without java.util.logging and jakarta.servlet.* dependency, so that Lincheck can run.

Method Summary

Modifier and Type	Method	Description
private void	assureReadyAndDrainedTurnsFalse()
(package private) void	complete()	Called from application thread.
(package private) void	flush()	Called from application thread.
(package private) void	onWritePossible()	Called from the container thread WriteListener.onWritePossible().
private void	runOrBuffer(AsyncServletOutputStreamWriter.ActionItem actionItem)	Either execute the write action directly, or buffer the action and let the container thread drain it.
(package private) void	writeBytes(byte[] bytes, int numBytes)	Called from application thread.

Methods inherited from class java.lang.Object

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

Field Detail

writeState

private final java.util.concurrent.atomic.AtomicReference<AsyncServletOutputStreamWriter.WriteState> writeState

Memory boundary for write actions.

 WriteState curState = writeState.get();  // mark a boundary
 doSomething();  // do something within the boundary
 boolean successful = writeState.compareAndSet(curState, newState); // try to mark a boundary
 if (successful) {
   // state has not changed since
   return;
 } else {
   // state is changed by another thread while doSomething(), need recompute
 }
 

There are two threads, the container thread (calling onWritePossible()) and the application thread (calling runOrBuffer()) that read and update the writeState. Only onWritePossible() may turn readyAndDrained from false to true, and only runOrBuffer() may turn it from true to false.

log

private final AsyncServletOutputStreamWriter.Log log

writeAction

private final java.util.function.BiFunction<byte[],java.lang.Integer,AsyncServletOutputStreamWriter.ActionItem> writeAction

flushAction

private final AsyncServletOutputStreamWriter.ActionItem flushAction

completeAction

private final AsyncServletOutputStreamWriter.ActionItem completeAction

isReady

private final java.util.function.BooleanSupplier isReady

writeChain

private final java.util.Queue<AsyncServletOutputStreamWriter.ActionItem> writeChain

New write actions will be buffered into this queue if the servlet output stream is not ready or the queue is not drained.

parkingThread

@Nullable
private volatile java.lang.Thread parkingThread

Constructor Detail

AsyncServletOutputStreamWriter

AsyncServletOutputStreamWriter(jakarta.servlet.AsyncContext asyncContext,
                               ServletServerStream.ServletTransportState transportState,
                               InternalLogId logId)
                        throws java.io.IOException

Throws:

java.io.IOException

AsyncServletOutputStreamWriter

AsyncServletOutputStreamWriter(java.util.function.BiFunction<byte[],java.lang.Integer,AsyncServletOutputStreamWriter.ActionItem> writeAction,
                               AsyncServletOutputStreamWriter.ActionItem flushAction,
                               AsyncServletOutputStreamWriter.ActionItem completeAction,
                               java.util.function.BooleanSupplier isReady,
                               AsyncServletOutputStreamWriter.Log log)

Constructor without java.util.logging and jakarta.servlet.* dependency, so that Lincheck can run.

Parameters:

writeAction - Provides an AsyncServletOutputStreamWriter.ActionItem to write given bytes with specified length.

isReady - Indicates whether the writer can write bytes at the moment (asynchronously).

Method Detail

writeBytes

void writeBytes(byte[] bytes,
                int numBytes)
         throws java.io.IOException

Called from application thread.

Throws:

java.io.IOException

flush

void flush()
    throws java.io.IOException

Called from application thread.

Throws:

java.io.IOException

complete

void complete()

Called from application thread.

onWritePossible

void onWritePossible()
              throws java.io.IOException

Called from the container thread WriteListener.onWritePossible().

Throws:

java.io.IOException

assureReadyAndDrainedTurnsFalse

private void assureReadyAndDrainedTurnsFalse()

runOrBuffer

private void runOrBuffer(AsyncServletOutputStreamWriter.ActionItem actionItem)
                  throws java.io.IOException

Either execute the write action directly, or buffer the action and let the container thread drain it.

Called from application thread.

Throws:

java.io.IOException