LocalIoHandler Class — netty Architecture

Source Code

transport/src/main/java/io/netty/channel/local/LocalIoHandler.java lines 33–155

public final class LocalIoHandler implements IoHandler {
    private final Set<LocalIoHandle> registeredChannels = new HashSet<LocalIoHandle>(64);
    private final ThreadAwareExecutor executor;
    private volatile Thread executionThread;

    private LocalIoHandler(ThreadAwareExecutor executor) {
        this.executor = Objects.requireNonNull(executor, "executor");
    }

    /**
     * Returns a new {@link IoHandlerFactory} that creates {@link LocalIoHandler} instances.
     */
    public static IoHandlerFactory newFactory() {
        return LocalIoHandler::new;
    }

    private static LocalIoHandle cast(IoHandle handle) {
        if (handle instanceof LocalIoHandle) {
            return (LocalIoHandle) handle;
        }
        throw new IllegalArgumentException("IoHandle of type " + StringUtil.simpleClassName(handle) + " not supported");
    }

    @Override
    public int run(IoHandlerContext context) {
        if (executionThread == null) {
            executionThread = Thread.currentThread();
        }
        if (context.canBlock()) {
            // Just block until there is a task ready to process or wakeup(...) is called.
            LockSupport.parkNanos(this, context.delayNanos(System.nanoTime()));
        }

        if (context.shouldReportActiveIoTime()) {
            context.reportActiveIoTime(0);
        }
        return 0;
    }

    @Override
    public void wakeup() {
        if (!executor.isExecutorThread(Thread.currentThread())) {
            Thread thread = executionThread;
            if (thread != null) {
                // Wakeup if we block at the moment.
                LockSupport.unpark(thread);
            }
        }
    }

    @Override
    public void prepareToDestroy() {
        for (LocalIoHandle handle : registeredChannels) {
            handle.closeNow();
        }
        registeredChannels.clear();
    }

    @Override
    public void destroy() {
    }

    @Override
    public IoRegistration register(IoHandle handle) {
        LocalIoHandle localHandle = cast(handle);
        if (registeredChannels.add(localHandle)) {
            LocalIoRegistration registration = new LocalIoRegistration(executor, localHandle);
            localHandle.registered();
            return registration;
        }
        throw new IllegalStateException();
    }

    @Override
    public boolean isCompatible(Class<? extends IoHandle> handleType) {
        return LocalIoHandle.class.isAssignableFrom(handleType);
    }

    private final class LocalIoRegistration implements IoRegistration {
        private final AtomicBoolean canceled = new AtomicBoolean();
        private final ThreadAwareExecutor executor;