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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.channel.embedded;

import java.net.SocketAddress;
import java.nio.channels.ClosedChannelException;
import java.util.ArrayDeque;
import java.util.Queue;
import java.util.concurrent.TimeUnit;

import io.netty.channel.AbstractChannel;
import io.netty.channel.Channel;
import io.netty.channel.ChannelConfig;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelId;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelMetadata;
import io.netty.channel.ChannelOutboundBuffer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.ChannelPromise;
import io.netty.channel.DefaultChannelConfig;
import io.netty.channel.DefaultChannelPipeline;
import io.netty.channel.EventLoop;
import io.netty.channel.RecvByteBufAllocator;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.RecyclableArrayList;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

/**
 * Base class for {@link Channel} implementations that are used in an embedded fashion.
 */
public class EmbeddedChannel extends AbstractChannel {

    private static final SocketAddress LOCAL_ADDRESS = new EmbeddedSocketAddress();
    private static final SocketAddress REMOTE_ADDRESS = new EmbeddedSocketAddress();

    private static final ChannelHandler[] EMPTY_HANDLERS = new ChannelHandler[0];
    private enum State { OPEN, ACTIVE, CLOSED }

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(EmbeddedChannel.class);

    private static final ChannelMetadata METADATA_NO_DISCONNECT = new ChannelMetadata(false);
    private static final ChannelMetadata METADATA_DISCONNECT = new ChannelMetadata(true);

    private final EmbeddedEventLoop loop = new EmbeddedEventLoop();
    private final ChannelFutureListener recordExceptionListener = new ChannelFutureListener() {
        @Override
        public void operationComplete(ChannelFuture future) throws Exception {
            recordException(future);
        }
    };

    private final ChannelMetadata metadata;
    private final ChannelConfig config;

    private Queue inboundMessages;
    private Queue outboundMessages;
    private Throwable lastException;
    private State state;

    /**
     * Create a new instance with an {@link EmbeddedChannelId} and an empty pipeline.
     */
    public EmbeddedChannel() {
        this(EMPTY_HANDLERS);
    }

    /**
     * Create a new instance with the specified ID and an empty pipeline.
     *
     * @param channelId the {@link ChannelId} that will be used to identify this channel
     */
    public EmbeddedChannel(ChannelId channelId) {
        this(channelId, EMPTY_HANDLERS);
    }

    /**
     * Create a new instance with the pipeline initialized with the specified handlers.
     *
     * @param handlers the {@link ChannelHandler}s which will be add in the {@link ChannelPipeline}
     */
    public EmbeddedChannel(ChannelHandler... handlers) {
        this(EmbeddedChannelId.INSTANCE, handlers);
    }

    /**
     * Create a new instance with the pipeline initialized with the specified handlers.
     *
     * @param hasDisconnect {@code false} if this {@link Channel} will delegate {@link #disconnect()}
     *                      to {@link #close()}, {@link false} otherwise.
     * @param handlers the {@link ChannelHandler}s which will be add in the {@link ChannelPipeline}
     */
    public EmbeddedChannel(boolean hasDisconnect, ChannelHandler... handlers) {
        this(EmbeddedChannelId.INSTANCE, hasDisconnect, handlers);
    }

    /**
     * Create a new instance with the pipeline initialized with the specified handlers.
     *
     * @param register {@code true} if this {@link Channel} is registered to the {@link EventLoop} in the
     *                 constructor. If {@code false} the user will need to call {@link #register()}.
     * @param hasDisconnect {@code false} if this {@link Channel} will delegate {@link #disconnect()}
     *                      to {@link #close()}, {@link false} otherwise.
     * @param handlers the {@link ChannelHandler}s which will be add in the {@link ChannelPipeline}
     */
    public EmbeddedChannel(boolean register, boolean hasDisconnect, ChannelHandler... handlers) {
        this(EmbeddedChannelId.INSTANCE, register, hasDisconnect, handlers);
    }

    /**
     * Create a new instance with the channel ID set to the given ID and the pipeline
     * initialized with the specified handlers.
     *
     * @param channelId the {@link ChannelId} that will be used to identify this channel
     * @param handlers the {@link ChannelHandler}s which will be add in the {@link ChannelPipeline}
     */
    public EmbeddedChannel(ChannelId channelId, ChannelHandler... handlers) {
        this(channelId, false, handlers);
    }

    /**
     * Create a new instance with the channel ID set to the given ID and the pipeline
     * initialized with the specified handlers.
     *
     * @param channelId the {@link ChannelId} that will be used to identify this channel
     * @param hasDisconnect {@code false} if this {@link Channel} will delegate {@link #disconnect()}
     *                      to {@link #close()}, {@link false} otherwise.
     * @param handlers the {@link ChannelHandler}s which will be add in the {@link ChannelPipeline}
     */
    public EmbeddedChannel(ChannelId channelId, boolean hasDisconnect, ChannelHandler... handlers) {
        this(channelId, true, hasDisconnect, handlers);
    }

    /**
     * Create a new instance with the channel ID set to the given ID and the pipeline
     * initialized with the specified handlers.
     *
     * @param channelId the {@link ChannelId} that will be used to identify this channel
     * @param register {@code true} if this {@link Channel} is registered to the {@link EventLoop} in the
     *                 constructor. If {@code false} the user will need to call {@link #register()}.
     * @param hasDisconnect {@code false} if this {@link Channel} will delegate {@link #disconnect()}
     *                      to {@link #close()}, {@link false} otherwise.
     * @param handlers the {@link ChannelHandler}s which will be add in the {@link ChannelPipeline}
     */
    public EmbeddedChannel(ChannelId channelId, boolean register, boolean hasDisconnect,
                           ChannelHandler... handlers) {
        this(null, channelId, register, hasDisconnect, handlers);
    }

    /**
     * Create a new instance with the channel ID set to the given ID and the pipeline
     * initialized with the specified handlers.
     *
     * @param parent    the parent {@link Channel} of this {@link EmbeddedChannel}.
     * @param channelId the {@link ChannelId} that will be used to identify this channel
     * @param register {@code true} if this {@link Channel} is registered to the {@link EventLoop} in the
     *                 constructor. If {@code false} the user will need to call {@link #register()}.
     * @param hasDisconnect {@code false} if this {@link Channel} will delegate {@link #disconnect()}
     *                      to {@link #close()}, {@link false} otherwise.
     * @param handlers the {@link ChannelHandler}s which will be add in the {@link ChannelPipeline}
     */
    public EmbeddedChannel(Channel parent, ChannelId channelId, boolean register, boolean hasDisconnect,
                           final ChannelHandler... handlers) {
        super(parent, channelId);
        metadata = metadata(hasDisconnect);
        config = new DefaultChannelConfig(this);
        setup(register, handlers);
    }

    /**
     * Create a new instance with the channel ID set to the given ID and the pipeline
     * initialized with the specified handlers.
     *
     * @param channelId the {@link ChannelId} that will be used to identify this channel
     * @param hasDisconnect {@code false} if this {@link Channel} will delegate {@link #disconnect()}
     *                      to {@link #close()}, {@link false} otherwise.
     * @param config the {@link ChannelConfig} which will be returned by {@link #config()}.
     * @param handlers the {@link ChannelHandler}s which will be add in the {@link ChannelPipeline}
     */
    public EmbeddedChannel(ChannelId channelId, boolean hasDisconnect, final ChannelConfig config,
                           final ChannelHandler... handlers) {
        super(null, channelId);
        metadata = metadata(hasDisconnect);
        this.config = ObjectUtil.checkNotNull(config, "config");
        setup(true, handlers);
    }

    private static ChannelMetadata metadata(boolean hasDisconnect) {
        return hasDisconnect ? METADATA_DISCONNECT : METADATA_NO_DISCONNECT;
    }

    private void setup(boolean register, final ChannelHandler... handlers) {
        ObjectUtil.checkNotNull(handlers, "handlers");
        ChannelPipeline p = pipeline();
        p.addLast(new ChannelInitializer() {
            @Override
            protected void initChannel(Channel ch) throws Exception {
                ChannelPipeline pipeline = ch.pipeline();
                for (ChannelHandler h: handlers) {
                    if (h == null) {
                        break;
                    }
                    pipeline.addLast(h);
                }
            }
        });
        if (register) {
            ChannelFuture future = loop.register(this);
            assert future.isDone();
        }
    }

    /**
     * Register this {@code Channel} on its {@link EventLoop}.
     */
    public void register() throws Exception {
        ChannelFuture future = loop.register(this);
        assert future.isDone();
        Throwable cause = future.cause();
        if (cause != null) {
            PlatformDependent.throwException(cause);
        }
    }

    @Override
    protected final DefaultChannelPipeline newChannelPipeline() {
        return new EmbeddedChannelPipeline(this);
    }

    @Override
    public ChannelMetadata metadata() {
        return metadata;
    }

    @Override
    public ChannelConfig config() {
        return config;
    }

    @Override
    public boolean isOpen() {
        return state != State.CLOSED;
    }

    @Override
    public boolean isActive() {
        return state == State.ACTIVE;
    }

    /**
     * Returns the {@link Queue} which holds all the {@link Object}s that were received by this {@link Channel}.
     */
    public Queue inboundMessages() {
        if (inboundMessages == null) {
            inboundMessages = new ArrayDeque();
        }
        return inboundMessages;
    }

    /**
     * @deprecated use {@link #inboundMessages()}
     */
    @Deprecated
    public Queue lastInboundBuffer() {
        return inboundMessages();
    }

    /**
     * Returns the {@link Queue} which holds all the {@link Object}s that were written by this {@link Channel}.
     */
    public Queue outboundMessages() {
        if (outboundMessages == null) {
            outboundMessages = new ArrayDeque();
        }
        return outboundMessages;
    }

    /**
     * @deprecated use {@link #outboundMessages()}
     */
    @Deprecated
    public Queue lastOutboundBuffer() {
        return outboundMessages();
    }

    /**
     * Return received data from this {@link Channel}
     */
    @SuppressWarnings("unchecked")
    public  T readInbound() {
        T message = (T) poll(inboundMessages);
        if (message != null) {
            ReferenceCountUtil.touch(message, "Caller of readInbound() will handle the message from this point");
        }
        return message;
    }

    /**
     * Read data from the outbound. This may return {@code null} if nothing is readable.
     */
    @SuppressWarnings("unchecked")
    public  T readOutbound() {
        T message =  (T) poll(outboundMessages);
        if (message != null) {
            ReferenceCountUtil.touch(message, "Caller of readOutbound() will handle the message from this point.");
        }
        return message;
    }

    /**
     * Write messages to the inbound of this {@link Channel}.
     *
     * @param msgs the messages to be written
     *
     * @return {@code true} if the write operation did add something to the inbound buffer
     */
    public boolean writeInbound(Object... msgs) {
        ensureOpen();
        if (msgs.length == 0) {
            return isNotEmpty(inboundMessages);
        }

        ChannelPipeline p = pipeline();
        for (Object m: msgs) {
            p.fireChannelRead(m);
        }

        flushInbound(false, voidPromise());
        return isNotEmpty(inboundMessages);
    }

    /**
     * Writes one message to the inbound of this {@link Channel} and does not flush it. This
     * method is conceptually equivalent to {@link #write(Object)}.
     *
     * @see #writeOneOutbound(Object)
     */
    public ChannelFuture writeOneInbound(Object msg) {
        return writeOneInbound(msg, newPromise());
    }

    /**
     * Writes one message to the inbound of this {@link Channel} and does not flush it. This
     * method is conceptually equivalent to {@link #write(Object, ChannelPromise)}.
     *
     * @see #writeOneOutbound(Object, ChannelPromise)
     */
    public ChannelFuture writeOneInbound(Object msg, ChannelPromise promise) {
        if (checkOpen(true)) {
            pipeline().fireChannelRead(msg);
        }
        return checkException(promise);
    }

    /**
     * Flushes the inbound of this {@link Channel}. This method is conceptually equivalent to {@link #flush()}.
     *
     * @see #flushOutbound()
     */
    public EmbeddedChannel flushInbound() {
        flushInbound(true, voidPromise());
        return this;
    }

    private ChannelFuture flushInbound(boolean recordException, ChannelPromise promise) {
      if (checkOpen(recordException)) {
          pipeline().fireChannelReadComplete();
          runPendingTasks();
      }

      return checkException(promise);
    }

    /**
     * Write messages to the outbound of this {@link Channel}.
     *
     * @param msgs              the messages to be written
     * @return bufferReadable   returns {@code true} if the write operation did add something to the outbound buffer
     */
    public boolean writeOutbound(Object... msgs) {
        ensureOpen();
        if (msgs.length == 0) {
            return isNotEmpty(outboundMessages);
        }

        RecyclableArrayList futures = RecyclableArrayList.newInstance(msgs.length);
        try {
            for (Object m: msgs) {
                if (m == null) {
                    break;
                }
                futures.add(write(m));
            }

            flushOutbound0();

            int size = futures.size();
            for (int i = 0; i < size; i++) {
                ChannelFuture future = (ChannelFuture) futures.get(i);
                if (future.isDone()) {
                    recordException(future);
                } else {
                    // The write may be delayed to run later by runPendingTasks()
                    future.addListener(recordExceptionListener);
                }
            }

            checkException();
            return isNotEmpty(outboundMessages);
        } finally {
            futures.recycle();
        }
    }

    /**
     * Writes one message to the outbound of this {@link Channel} and does not flush it. This
     * method is conceptually equivalent to {@link #write(Object)}.
     *
     * @see #writeOneInbound(Object)
     */
    public ChannelFuture writeOneOutbound(Object msg) {
        return writeOneOutbound(msg, newPromise());
    }

    /**
     * Writes one message to the outbound of this {@link Channel} and does not flush it. This
     * method is conceptually equivalent to {@link #write(Object, ChannelPromise)}.
     *
     * @see #writeOneInbound(Object, ChannelPromise)
     */
    public ChannelFuture writeOneOutbound(Object msg, ChannelPromise promise) {
        if (checkOpen(true)) {
            return write(msg, promise);
        }
        return checkException(promise);
    }

    /**
     * Flushes the outbound of this {@link Channel}. This method is conceptually equivalent to {@link #flush()}.
     *
     * @see #flushInbound()
     */
    public EmbeddedChannel flushOutbound() {
        if (checkOpen(true)) {
            flushOutbound0();
        }
        checkException(voidPromise());
        return this;
    }

    private void flushOutbound0() {
        // We need to call runPendingTasks first as a ChannelOutboundHandler may used eventloop.execute(...) to
        // delay the write on the next eventloop run.
        runPendingTasks();

        flush();
    }

    /**
     * Mark this {@link Channel} as finished. Any further try to write data to it will fail.
     *
     * @return bufferReadable returns {@code true} if any of the used buffers has something left to read
     */
    public boolean finish() {
        return finish(false);
    }

    /**
     * Mark this {@link Channel} as finished and release all pending message in the inbound and outbound buffer.
     * Any further try to write data to it will fail.
     *
     * @return bufferReadable returns {@code true} if any of the used buffers has something left to read
     */
    public boolean finishAndReleaseAll() {
        return finish(true);
    }

    /**
     * Mark this {@link Channel} as finished. Any further try to write data to it will fail.
     *
     * @param releaseAll if {@code true} all pending message in the inbound and outbound buffer are released.
     * @return bufferReadable returns {@code true} if any of the used buffers has something left to read
     */
    private boolean finish(boolean releaseAll) {
        close();
        try {
            checkException();
            return isNotEmpty(inboundMessages) || isNotEmpty(outboundMessages);
        } finally {
            if (releaseAll) {
                releaseAll(inboundMessages);
                releaseAll(outboundMessages);
            }
        }
    }

    /**
     * Release all buffered inbound messages and return {@code true} if any were in the inbound buffer, {@code false}
     * otherwise.
     */
    public boolean releaseInbound() {
        return releaseAll(inboundMessages);
    }

    /**
     * Release all buffered outbound messages and return {@code true} if any were in the outbound buffer, {@code false}
     * otherwise.
     */
    public boolean releaseOutbound() {
        return releaseAll(outboundMessages);
    }

    private static boolean releaseAll(Queue queue) {
        if (isNotEmpty(queue)) {
            for (;;) {
                Object msg = queue.poll();
                if (msg == null) {
                    break;
                }
                ReferenceCountUtil.release(msg);
            }
            return true;
        }
        return false;
    }

    private void finishPendingTasks(boolean cancel) {
        runPendingTasks();
        if (cancel) {
            // Cancel all scheduled tasks that are left.
            embeddedEventLoop().cancelScheduledTasks();
        }
    }

    @Override
    public final ChannelFuture close() {
        return close(newPromise());
    }

    @Override
    public final ChannelFuture disconnect() {
        return disconnect(newPromise());
    }

    @Override
    public final ChannelFuture close(ChannelPromise promise) {
        // We need to call runPendingTasks() before calling super.close() as there may be something in the queue
        // that needs to be run before the actual close takes place.
        runPendingTasks();
        ChannelFuture future = super.close(promise);

        // Now finish everything else and cancel all scheduled tasks that were not ready set.
        finishPendingTasks(true);
        return future;
    }

    @Override
    public final ChannelFuture disconnect(ChannelPromise promise) {
        ChannelFuture future = super.disconnect(promise);
        finishPendingTasks(!metadata.hasDisconnect());
        return future;
    }

    private static boolean isNotEmpty(Queue queue) {
        return queue != null && !queue.isEmpty();
    }

    private static Object poll(Queue queue) {
        return queue != null ? queue.poll() : null;
    }

    /**
     * Run all tasks (which also includes scheduled tasks) that are pending in the {@link EventLoop}
     * for this {@link Channel}
     */
    public void runPendingTasks() {
        try {
            embeddedEventLoop().runTasks();
        } catch (Exception e) {
            recordException(e);
        }

        try {
            embeddedEventLoop().runScheduledTasks();
        } catch (Exception e) {
            recordException(e);
        }
    }

    /**
     * Check whether this channel has any pending tasks that would be executed by a call to {@link #runPendingTasks()}.
     * This includes normal tasks, and scheduled tasks where the deadline has expired. If this method returns
     * {@code false}, a call to {@link #runPendingTasks()} would do nothing.
     *
     * @return {@code true} if there are any pending tasks, {@code false} otherwise.
     */
    public boolean hasPendingTasks() {
        return embeddedEventLoop().hasPendingNormalTasks() ||
                embeddedEventLoop().nextScheduledTask() == 0;
    }

    /**
     * Run all pending scheduled tasks in the {@link EventLoop} for this {@link Channel} and return the
     * {@code nanoseconds} when the next scheduled task is ready to run. If no other task was scheduled it will return
     * {@code -1}.
     */
    public long runScheduledPendingTasks() {
        try {
            return embeddedEventLoop().runScheduledTasks();
        } catch (Exception e) {
            recordException(e);
            return embeddedEventLoop().nextScheduledTask();
        }
    }

    private void recordException(ChannelFuture future) {
        if (!future.isSuccess()) {
            recordException(future.cause());
        }
    }

    private void recordException(Throwable cause) {
        if (lastException == null) {
            lastException = cause;
        } else {
            logger.warn(
                    "More than one exception was raised. " +
                            "Will report only the first one and log others.", cause);
        }
    }

    /**
     * Advance the clock of the event loop of this channel by the given duration. Any scheduled tasks will execute
     * sooner by the given time (but {@link #runScheduledPendingTasks()} still needs to be called).
     */
    public void advanceTimeBy(long duration, TimeUnit unit) {
        embeddedEventLoop().advanceTimeBy(unit.toNanos(duration));
    }

    /**
     * Freeze the clock of this channel's event loop. Any scheduled tasks that are not already due will not run on
     * future {@link #runScheduledPendingTasks()} calls. While the event loop is frozen, it is still possible to
     * {@link #advanceTimeBy(long, TimeUnit) advance time} manually so that scheduled tasks execute.
     */
    public void freezeTime() {
        embeddedEventLoop().freezeTime();
    }

    /**
     * Unfreeze an event loop that was {@link #freezeTime() frozen}. Time will continue at the point where
     * {@link #freezeTime()} stopped it: if a task was scheduled ten minutes in the future and {@link #freezeTime()}
     * was called, it will run ten minutes after this method is called again (assuming no
     * {@link #advanceTimeBy(long, TimeUnit)} calls, and assuming pending scheduled tasks are run at that time using
     * {@link #runScheduledPendingTasks()}).
     */
    public void unfreezeTime() {
        embeddedEventLoop().unfreezeTime();
    }

    /**
     * Checks for the presence of an {@link Exception}.
     */
    private ChannelFuture checkException(ChannelPromise promise) {
      Throwable t = lastException;
      if (t != null) {
        lastException = null;

        if (promise.isVoid()) {
            PlatformDependent.throwException(t);
        }

        return promise.setFailure(t);
      }

      return promise.setSuccess();
    }

    /**
     * Check if there was any {@link Throwable} received and if so rethrow it.
     */
    public void checkException() {
      checkException(voidPromise());
    }

    /**
     * Returns {@code true} if the {@link Channel} is open and records optionally
     * an {@link Exception} if it isn't.
     */
    private boolean checkOpen(boolean recordException) {
        if (!isOpen()) {
          if (recordException) {
              recordException(new ClosedChannelException());
          }
          return false;
      }

      return true;
    }

    private EmbeddedEventLoop embeddedEventLoop() {
        if (isRegistered()) {
            return (EmbeddedEventLoop) super.eventLoop();
        }

        return loop;
    }

    /**
     * Ensure the {@link Channel} is open and if not throw an exception.
     */
    protected final void ensureOpen() {
        if (!checkOpen(true)) {
            checkException();
        }
    }

    @Override
    protected boolean isCompatible(EventLoop loop) {
        return loop instanceof EmbeddedEventLoop;
    }

    @Override
    protected SocketAddress localAddress0() {
        return isActive()? LOCAL_ADDRESS : null;
    }

    @Override
    protected SocketAddress remoteAddress0() {
        return isActive()? REMOTE_ADDRESS : null;
    }

    @Override
    protected void doRegister() throws Exception {
        state = State.ACTIVE;
    }

    @Override
    protected void doBind(SocketAddress localAddress) throws Exception {
        // NOOP
    }

    @Override
    protected void doDisconnect() throws Exception {
        if (!metadata.hasDisconnect()) {
            doClose();
        }
    }

    @Override
    protected void doClose() throws Exception {
        state = State.CLOSED;
    }

    @Override
    protected void doBeginRead() throws Exception {
        // NOOP
    }

    @Override
    protected AbstractUnsafe newUnsafe() {
        return new EmbeddedUnsafe();
    }

    @Override
    public Unsafe unsafe() {
        return ((EmbeddedUnsafe) super.unsafe()).wrapped;
    }

    @Override
    protected void doWrite(ChannelOutboundBuffer in) throws Exception {
        for (;;) {
            Object msg = in.current();
            if (msg == null) {
                break;
            }

            ReferenceCountUtil.retain(msg);
            handleOutboundMessage(msg);
            in.remove();
        }
    }

    /**
     * Called for each outbound message.
     *
     * @see #doWrite(ChannelOutboundBuffer)
     */
    protected void handleOutboundMessage(Object msg) {
        outboundMessages().add(msg);
    }

    /**
     * Called for each inbound message.
     */
    protected void handleInboundMessage(Object msg) {
        inboundMessages().add(msg);
    }

    private final class EmbeddedUnsafe extends AbstractUnsafe {

        // Delegates to the EmbeddedUnsafe instance but ensures runPendingTasks() is called after each operation
        // that may change the state of the Channel and may schedule tasks for later execution.
        final Unsafe wrapped = new Unsafe() {
            @Override
            public RecvByteBufAllocator.Handle recvBufAllocHandle() {
                return EmbeddedUnsafe.this.recvBufAllocHandle();
            }

            @Override
            public SocketAddress localAddress() {
                return EmbeddedUnsafe.this.localAddress();
            }

            @Override
            public SocketAddress remoteAddress() {
                return EmbeddedUnsafe.this.remoteAddress();
            }

            @Override
            public void register(EventLoop eventLoop, ChannelPromise promise) {
                EmbeddedUnsafe.this.register(eventLoop, promise);
                runPendingTasks();
            }

            @Override
            public void bind(SocketAddress localAddress, ChannelPromise promise) {
                EmbeddedUnsafe.this.bind(localAddress, promise);
                runPendingTasks();
            }

            @Override
            public void connect(SocketAddress remoteAddress, SocketAddress localAddress, ChannelPromise promise) {
                EmbeddedUnsafe.this.connect(remoteAddress, localAddress, promise);
                runPendingTasks();
            }

            @Override
            public void disconnect(ChannelPromise promise) {
                EmbeddedUnsafe.this.disconnect(promise);
                runPendingTasks();
            }

            @Override
            public void close(ChannelPromise promise) {
                EmbeddedUnsafe.this.close(promise);
                runPendingTasks();
            }

            @Override
            public void closeForcibly() {
                EmbeddedUnsafe.this.closeForcibly();
                runPendingTasks();
            }

            @Override
            public void deregister(ChannelPromise promise) {
                EmbeddedUnsafe.this.deregister(promise);
                runPendingTasks();
            }

            @Override
            public void beginRead() {
                EmbeddedUnsafe.this.beginRead();
                runPendingTasks();
            }

            @Override
            public void write(Object msg, ChannelPromise promise) {
                EmbeddedUnsafe.this.write(msg, promise);
                runPendingTasks();
            }

            @Override
            public void flush() {
                EmbeddedUnsafe.this.flush();
                runPendingTasks();
            }

            @Override
            public ChannelPromise voidPromise() {
                return EmbeddedUnsafe.this.voidPromise();
            }

            @Override
            public ChannelOutboundBuffer outboundBuffer() {
                return EmbeddedUnsafe.this.outboundBuffer();
            }
        };

        @Override
        public void connect(SocketAddress remoteAddress, SocketAddress localAddress, ChannelPromise promise) {
            safeSetSuccess(promise);
        }
    }

    private final class EmbeddedChannelPipeline extends DefaultChannelPipeline {
        EmbeddedChannelPipeline(EmbeddedChannel channel) {
            super(channel);
        }

        @Override
        protected void onUnhandledInboundException(Throwable cause) {
            recordException(cause);
        }

        @Override
        protected void onUnhandledInboundMessage(ChannelHandlerContext ctx, Object msg) {
            handleInboundMessage(msg);
        }
    }
}