ThreadExecutorMap Class — netty Architecture

Source Code

common/src/main/java/io/netty/util/internal/ThreadExecutorMap.java lines 27–96

public final class ThreadExecutorMap {

    private static final FastThreadLocal<EventExecutor> mappings = new FastThreadLocal<EventExecutor>();

    private ThreadExecutorMap() { }

    /**
     * Returns the current {@link EventExecutor} that uses the {@link Thread}, or {@code null} if none / unknown.
     */
    public static EventExecutor currentExecutor() {
        return mappings.get();
    }

    /**
     * Set the current {@link EventExecutor} that is used by the {@link Thread}.
     */
    public static EventExecutor setCurrentExecutor(EventExecutor executor) {
        return mappings.getAndSet(executor);
    }

    /**
     * Decorate the given {@link Executor} and ensure {@link #currentExecutor()} will return {@code eventExecutor}
     * when called from within the {@link Runnable} during execution.
     */
    public static Executor apply(final Executor executor, final EventExecutor eventExecutor) {
        ObjectUtil.checkNotNull(executor, "executor");
        ObjectUtil.checkNotNull(eventExecutor, "eventExecutor");
        return new Executor() {
            @Override
            public void execute(final Runnable command) {
                executor.execute(apply(command, eventExecutor));
            }
        };
    }

    /**
     * Decorate the given {@link Runnable} and ensure {@link #currentExecutor()} will return {@code eventExecutor}
     * when called from within the {@link Runnable} during execution.
     */
    public static Runnable apply(final Runnable command, final EventExecutor eventExecutor) {
        ObjectUtil.checkNotNull(command, "command");
        ObjectUtil.checkNotNull(eventExecutor, "eventExecutor");
        return new Runnable() {
            @Override
            public void run() {
                EventExecutor old = setCurrentExecutor(eventExecutor);
                try {
                    command.run();
                } finally {
                    setCurrentExecutor(old);
                }
            }
        };
    }

    /**
     * Decorate the given {@link ThreadFactory} and ensure {@link #currentExecutor()} will return {@code eventExecutor}
     * when called from within the {@link Runnable} during execution.
     */
    public static ThreadFactory apply(final ThreadFactory threadFactory, final EventExecutor eventExecutor) {
        ObjectUtil.checkNotNull(threadFactory, "threadFactory");
        ObjectUtil.checkNotNull(eventExecutor, "eventExecutor");
        return new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                return threadFactory.newThread(apply(r, eventExecutor));
            }
        };
    }
}