Java example source code file (AbstractChannel.java)
The AbstractChannel.java Java example source code/*
* 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:
*
* http://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;
import io.netty.buffer.ByteBufAllocator;
import io.netty.util.DefaultAttributeMap;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.ThrowableUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.io.IOException;
import java.net.ConnectException;
import java.net.InetSocketAddress;
import java.net.NoRouteToHostException;
import java.net.SocketAddress;
import java.net.SocketException;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.NotYetConnectedException;
import java.util.concurrent.Executor;
import java.util.concurrent.RejectedExecutionException;
/**
* A skeletal {@link Channel} implementation.
*/
public abstract class AbstractChannel extends DefaultAttributeMap implements Channel {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(AbstractChannel.class);
private static final ClosedChannelException FLUSH0_CLOSED_CHANNEL_EXCEPTION = ThrowableUtil.unknownStackTrace(
new ClosedChannelException(), AbstractUnsafe.class, "flush0()");
private static final ClosedChannelException ENSURE_OPEN_CLOSED_CHANNEL_EXCEPTION = ThrowableUtil.unknownStackTrace(
new ClosedChannelException(), AbstractUnsafe.class, "ensureOpen(...)");
private static final ClosedChannelException CLOSE_CLOSED_CHANNEL_EXCEPTION = ThrowableUtil.unknownStackTrace(
new ClosedChannelException(), AbstractUnsafe.class, "close(...)");
private static final ClosedChannelException WRITE_CLOSED_CHANNEL_EXCEPTION = ThrowableUtil.unknownStackTrace(
new ClosedChannelException(), AbstractUnsafe.class, "write(...)");
private static final NotYetConnectedException FLUSH0_NOT_YET_CONNECTED_EXCEPTION = ThrowableUtil.unknownStackTrace(
new NotYetConnectedException(), AbstractUnsafe.class, "flush0()");
private final Channel parent;
private final ChannelId id;
private final Unsafe unsafe;
private final DefaultChannelPipeline pipeline;
private final VoidChannelPromise unsafeVoidPromise = new VoidChannelPromise(this, false);
private final CloseFuture closeFuture = new CloseFuture(this);
private volatile SocketAddress localAddress;
private volatile SocketAddress remoteAddress;
private volatile EventLoop eventLoop;
private volatile boolean registered;
/** Cache for the string representation of this channel */
private boolean strValActive;
private String strVal;
/**
* Creates a new instance.
*
* @param parent
* the parent of this channel. {@code null} if there's no parent.
*/
protected AbstractChannel(Channel parent) {
this.parent = parent;
id = newId();
unsafe = newUnsafe();
pipeline = newChannelPipeline();
}
/**
* Creates a new instance.
*
* @param parent
* the parent of this channel. {@code null} if there's no parent.
*/
protected AbstractChannel(Channel parent, ChannelId id) {
this.parent = parent;
this.id = id;
unsafe = newUnsafe();
pipeline = newChannelPipeline();
}
@Override
public final ChannelId id() {
return id;
}
/**
* Returns a new {@link DefaultChannelId} instance. Subclasses may override this method to assign custom
* {@link ChannelId}s to {@link Channel}s that use the {@link AbstractChannel#AbstractChannel(Channel)} constructor.
*/
protected ChannelId newId() {
return DefaultChannelId.newInstance();
}
/**
* Returns a new {@link DefaultChannelPipeline} instance.
*/
protected DefaultChannelPipeline newChannelPipeline() {
return new DefaultChannelPipeline(this);
}
@Override
public boolean isWritable() {
ChannelOutboundBuffer buf = unsafe.outboundBuffer();
return buf != null && buf.isWritable();
}
@Override
public long bytesBeforeUnwritable() {
ChannelOutboundBuffer buf = unsafe.outboundBuffer();
// isWritable() is currently assuming if there is no outboundBuffer then the channel is not writable.
// We should be consistent with that here.
return buf != null ? buf.bytesBeforeUnwritable() : 0;
}
@Override
public long bytesBeforeWritable() {
ChannelOutboundBuffer buf = unsafe.outboundBuffer();
// isWritable() is currently assuming if there is no outboundBuffer then the channel is not writable.
// We should be consistent with that here.
return buf != null ? buf.bytesBeforeWritable() : Long.MAX_VALUE;
}
@Override
public Channel parent() {
return parent;
}
@Override
public ChannelPipeline pipeline() {
return pipeline;
}
@Override
public ByteBufAllocator alloc() {
return config().getAllocator();
}
@Override
public EventLoop eventLoop() {
EventLoop eventLoop = this.eventLoop;
if (eventLoop == null) {
throw new IllegalStateException("channel not registered to an event loop");
}
return eventLoop;
}
@Override
public SocketAddress localAddress() {
SocketAddress localAddress = this.localAddress;
if (localAddress == null) {
try {
this.localAddress = localAddress = unsafe().localAddress();
} catch (Throwable t) {
// Sometimes fails on a closed socket in Windows.
return null;
}
}
return localAddress;
}
protected void invalidateLocalAddress() {
localAddress = null;
}
@Override
public SocketAddress remoteAddress() {
SocketAddress remoteAddress = this.remoteAddress;
if (remoteAddress == null) {
try {
this.remoteAddress = remoteAddress = unsafe().remoteAddress();
} catch (Throwable t) {
// Sometimes fails on a closed socket in Windows.
return null;
}
}
return remoteAddress;
}
/**
* Reset the stored remoteAddress
*/
protected void invalidateRemoteAddress() {
remoteAddress = null;
}
@Override
public boolean isRegistered() {
return registered;
}
@Override
public ChannelFuture bind(SocketAddress localAddress) {
return pipeline.bind(localAddress);
}
@Override
public ChannelFuture connect(SocketAddress remoteAddress) {
return pipeline.connect(remoteAddress);
}
@Override
public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress) {
return pipeline.connect(remoteAddress, localAddress);
}
@Override
public ChannelFuture disconnect() {
return pipeline.disconnect();
}
@Override
public ChannelFuture close() {
return pipeline.close();
}
@Override
public ChannelFuture deregister() {
return pipeline.deregister();
}
@Override
public Channel flush() {
pipeline.flush();
return this;
}
@Override
public ChannelFuture bind(SocketAddress localAddress, ChannelPromise promise) {
return pipeline.bind(localAddress, promise);
}
@Override
public ChannelFuture connect(SocketAddress remoteAddress, ChannelPromise promise) {
return pipeline.connect(remoteAddress, promise);
}
@Override
public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress, ChannelPromise promise) {
return pipeline.connect(remoteAddress, localAddress, promise);
}
@Override
public ChannelFuture disconnect(ChannelPromise promise) {
return pipeline.disconnect(promise);
}
@Override
public ChannelFuture close(ChannelPromise promise) {
return pipeline.close(promise);
}
@Override
public ChannelFuture deregister(ChannelPromise promise) {
return pipeline.deregister(promise);
}
@Override
public Channel read() {
pipeline.read();
return this;
}
@Override
public ChannelFuture write(Object msg) {
return pipeline.write(msg);
}
@Override
public ChannelFuture write(Object msg, ChannelPromise promise) {
return pipeline.write(msg, promise);
}
@Override
public ChannelFuture writeAndFlush(Object msg) {
return pipeline.writeAndFlush(msg);
}
@Override
public ChannelFuture writeAndFlush(Object msg, ChannelPromise promise) {
return pipeline.writeAndFlush(msg, promise);
}
@Override
public ChannelPromise newPromise() {
return pipeline.newPromise();
}
@Override
public ChannelProgressivePromise newProgressivePromise() {
return pipeline.newProgressivePromise();
}
@Override
public ChannelFuture newSucceededFuture() {
return pipeline.newSucceededFuture();
}
@Override
public ChannelFuture newFailedFuture(Throwable cause) {
return pipeline.newFailedFuture(cause);
}
@Override
public ChannelFuture closeFuture() {
return closeFuture;
}
@Override
public Unsafe unsafe() {
return unsafe;
}
/**
* Create a new {@link AbstractUnsafe} instance which will be used for the life-time of the {@link Channel}
*/
protected abstract AbstractUnsafe newUnsafe();
/**
* Returns the ID of this channel.
*/
@Override
public final int hashCode() {
return id.hashCode();
}
/**
* Returns {@code true} if and only if the specified object is identical
* with this channel (i.e: {@code this == o}).
*/
@Override
public final boolean equals(Object o) {
return this == o;
}
@Override
public final int compareTo(Channel o) {
if (this == o) {
return 0;
}
return id().compareTo(o.id());
}
/**
* Returns the {@link String} representation of this channel. The returned
* string contains the {@linkplain #hashCode()} ID}, {@linkplain #localAddress() local address},
* and {@linkplain #remoteAddress() remote address} of this channel for
* easier identification.
*/
@Override
public String toString() {
boolean active = isActive();
if (strValActive == active && strVal != null) {
return strVal;
}
SocketAddress remoteAddr = remoteAddress();
SocketAddress localAddr = localAddress();
if (remoteAddr != null) {
StringBuilder buf = new StringBuilder(96)
.append("[id: 0x")
.append(id.asShortText())
.append(", L:")
.append(localAddr)
.append(active? " - " : " ! ")
.append("R:")
.append(remoteAddr)
.append(']');
strVal = buf.toString();
} else if (localAddr != null) {
StringBuilder buf = new StringBuilder(64)
.append("[id: 0x")
.append(id.asShortText())
.append(", L:")
.append(localAddr)
.append(']');
strVal = buf.toString();
} else {
StringBuilder buf = new StringBuilder(16)
.append("[id: 0x")
.append(id.asShortText())
.append(']');
strVal = buf.toString();
}
strValActive = active;
return strVal;
}
@Override
public final ChannelPromise voidPromise() {
return pipeline.voidPromise();
}
/**
* {@link Unsafe} implementation which sub-classes must extend and use.
*/
protected abstract class AbstractUnsafe implements Unsafe {
private ChannelOutboundBuffer outboundBuffer = new ChannelOutboundBuffer(AbstractChannel.this);
private RecvByteBufAllocator.Handle recvHandle;
private boolean inFlush0;
/** true if the channel has never been registered, false otherwise */
private boolean neverRegistered = true;
private void assertEventLoop() {
assert !registered || eventLoop.inEventLoop();
}
@Override
public RecvByteBufAllocator.Handle recvBufAllocHandle() {
if (recvHandle == null) {
recvHandle = config().getRecvByteBufAllocator().newHandle();
}
return recvHandle;
}
@Override
public final ChannelOutboundBuffer outboundBuffer() {
return outboundBuffer;
}
@Override
public final SocketAddress localAddress() {
return localAddress0();
}
@Override
public final SocketAddress remoteAddress() {
return remoteAddress0();
}
@Override
public final void register(EventLoop eventLoop, final ChannelPromise promise) {
if (eventLoop == null) {
throw new NullPointerException("eventLoop");
}
if (isRegistered()) {
promise.setFailure(new IllegalStateException("registered to an event loop already"));
return;
}
if (!isCompatible(eventLoop)) {
promise.setFailure(
new IllegalStateException("incompatible event loop type: " + eventLoop.getClass().getName()));
return;
}
AbstractChannel.this.eventLoop = eventLoop;
if (eventLoop.inEventLoop()) {
register0(promise);
} else {
try {
eventLoop.execute(new Runnable() {
@Override
public void run() {
register0(promise);
}
});
} catch (Throwable t) {
logger.warn(
"Force-closing a channel whose registration task was not accepted by an event loop: {}",
AbstractChannel.this, t);
closeForcibly();
closeFuture.setClosed();
safeSetFailure(promise, t);
}
}
}
private void register0(ChannelPromise promise) {
try {
// check if the channel is still open as it could be closed in the mean time when the register
// call was outside of the eventLoop
if (!promise.setUncancellable() || !ensureOpen(promise)) {
return;
}
boolean firstRegistration = neverRegistered;
doRegister();
neverRegistered = false;
registered = true;
safeSetSuccess(promise);
pipeline.fireChannelRegistered();
// Only fire a channelActive if the channel has never been registered. This prevents firing
// multiple channel actives if the channel is deregistered and re-registered.
if (isActive()) {
if (firstRegistration) {
pipeline.fireChannelActive();
} else if (config().isAutoRead()) {
// This channel was registered before and autoRead() is set. This means we need to begin read
// again so that we process inbound data.
//
// See https://github.com/netty/netty/issues/4805
beginRead();
}
}
} catch (Throwable t) {
// Close the channel directly to avoid FD leak.
closeForcibly();
closeFuture.setClosed();
safeSetFailure(promise, t);
}
}
@Override
public final void bind(final SocketAddress localAddress, final ChannelPromise promise) {
assertEventLoop();
if (!promise.setUncancellable() || !ensureOpen(promise)) {
return;
}
// See: https://github.com/netty/netty/issues/576
if (Boolean.TRUE.equals(config().getOption(ChannelOption.SO_BROADCAST)) &&
localAddress instanceof InetSocketAddress &&
!((InetSocketAddress) localAddress).getAddress().isAnyLocalAddress() &&
!PlatformDependent.isWindows() && !PlatformDependent.isRoot()) {
// Warn a user about the fact that a non-root user can't receive a
// broadcast packet on *nix if the socket is bound on non-wildcard address.
logger.warn(
"A non-root user can't receive a broadcast packet if the socket " +
"is not bound to a wildcard address; binding to a non-wildcard " +
"address (" + localAddress + ") anyway as requested.");
}
boolean wasActive = isActive();
try {
doBind(localAddress);
} catch (Throwable t) {
safeSetFailure(promise, t);
closeIfClosed();
return;
}
if (!wasActive && isActive()) {
invokeLater(new Runnable() {
@Override
public void run() {
pipeline.fireChannelActive();
}
});
}
safeSetSuccess(promise);
}
@Override
public final void disconnect(final ChannelPromise promise) {
assertEventLoop();
if (!promise.setUncancellable()) {
return;
}
boolean wasActive = isActive();
try {
doDisconnect();
} catch (Throwable t) {
safeSetFailure(promise, t);
closeIfClosed();
return;
}
if (wasActive && !isActive()) {
invokeLater(new Runnable() {
@Override
public void run() {
pipeline.fireChannelInactive();
}
});
}
safeSetSuccess(promise);
closeIfClosed(); // doDisconnect() might have closed the channel
}
@Override
public final void close(final ChannelPromise promise) {
assertEventLoop();
close(promise, CLOSE_CLOSED_CHANNEL_EXCEPTION, CLOSE_CLOSED_CHANNEL_EXCEPTION, false);
}
private void close(final ChannelPromise promise, final Throwable cause,
final ClosedChannelException closeCause, final boolean notify) {
if (!promise.setUncancellable()) {
return;
}
final ChannelOutboundBuffer outboundBuffer = this.outboundBuffer;
if (outboundBuffer == null) {
// Only needed if no VoidChannelPromise.
if (!(promise instanceof VoidChannelPromise)) {
// This means close() was called before so we just register a listener and return
closeFuture.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
promise.setSuccess();
}
});
}
return;
}
if (closeFuture.isDone()) {
// Closed already.
safeSetSuccess(promise);
return;
}
final boolean wasActive = isActive();
this.outboundBuffer = null; // Disallow adding any messages and flushes to outboundBuffer.
Executor closeExecutor = prepareToClose();
if (closeExecutor != null) {
closeExecutor.execute(new Runnable() {
@Override
public void run() {
try {
// Execute the close.
doClose0(promise);
} finally {
// Call invokeLater so closeAndDeregister is executed in the EventLoop again!
invokeLater(new Runnable() {
@Override
public void run() {
// Fail all the queued messages
outboundBuffer.failFlushed(cause, notify);
outboundBuffer.close(closeCause);
fireChannelInactiveAndDeregister(wasActive);
}
});
}
}
});
} else {
try {
// Close the channel and fail the queued messages in all cases.
doClose0(promise);
} finally {
// Fail all the queued messages.
outboundBuffer.failFlushed(cause, notify);
outboundBuffer.close(closeCause);
}
if (inFlush0) {
invokeLater(new Runnable() {
@Override
public void run() {
fireChannelInactiveAndDeregister(wasActive);
}
});
} else {
fireChannelInactiveAndDeregister(wasActive);
}
}
}
private void doClose0(ChannelPromise promise) {
try {
doClose();
closeFuture.setClosed();
safeSetSuccess(promise);
} catch (Throwable t) {
closeFuture.setClosed();
safeSetFailure(promise, t);
}
}
private void fireChannelInactiveAndDeregister(final boolean wasActive) {
deregister(voidPromise(), wasActive && !isActive());
}
@Override
public final void closeForcibly() {
assertEventLoop();
try {
doClose();
} catch (Exception e) {
logger.warn("Failed to close a channel.", e);
}
}
@Override
public final void deregister(final ChannelPromise promise) {
assertEventLoop();
deregister(promise, false);
}
private void deregister(final ChannelPromise promise, final boolean fireChannelInactive) {
if (!promise.setUncancellable()) {
return;
}
if (!registered) {
safeSetSuccess(promise);
return;
}
// As a user may call deregister() from within any method while doing processing in the ChannelPipeline,
// we need to ensure we do the actual deregister operation later. This is needed as for example,
// we may be in the ByteToMessageDecoder.callDecode(...) method and so still try to do processing in
// the old EventLoop while the user already registered the Channel to a new EventLoop. Without delay,
// the deregister operation this could lead to have a handler invoked by different EventLoop and so
// threads.
//
// See:
// https://github.com/netty/netty/issues/4435
invokeLater(new Runnable() {
@Override
public void run() {
try {
doDeregister();
} catch (Throwable t) {
logger.warn("Unexpected exception occurred while deregistering a channel.", t);
} finally {
if (fireChannelInactive) {
pipeline.fireChannelInactive();
}
// Some transports like local and AIO does not allow the deregistration of
// an open channel. Their doDeregister() calls close(). Consequently,
// close() calls deregister() again - no need to fire channelUnregistered, so check
// if it was registered.
if (registered) {
registered = false;
pipeline.fireChannelUnregistered();
}
safeSetSuccess(promise);
}
}
});
}
@Override
public final void beginRead() {
assertEventLoop();
if (!isActive()) {
return;
}
try {
doBeginRead();
} catch (final Exception e) {
invokeLater(new Runnable() {
@Override
public void run() {
pipeline.fireExceptionCaught(e);
}
});
close(voidPromise());
}
}
@Override
public final void write(Object msg, ChannelPromise promise) {
assertEventLoop();
ChannelOutboundBuffer outboundBuffer = this.outboundBuffer;
if (outboundBuffer == null) {
// If the outboundBuffer is null we know the channel was closed and so
// need to fail the future right away. If it is not null the handling of the rest
// will be done in flush0()
// See https://github.com/netty/netty/issues/2362
safeSetFailure(promise, WRITE_CLOSED_CHANNEL_EXCEPTION);
// release message now to prevent resource-leak
ReferenceCountUtil.release(msg);
return;
}
int size;
try {
msg = filterOutboundMessage(msg);
size = pipeline.estimatorHandle().size(msg);
if (size < 0) {
size = 0;
}
} catch (Throwable t) {
safeSetFailure(promise, t);
ReferenceCountUtil.release(msg);
return;
}
outboundBuffer.addMessage(msg, size, promise);
}
@Override
public final void flush() {
assertEventLoop();
ChannelOutboundBuffer outboundBuffer = this.outboundBuffer;
if (outboundBuffer == null) {
return;
}
outboundBuffer.addFlush();
flush0();
}
@SuppressWarnings("deprecation")
protected void flush0() {
if (inFlush0) {
// Avoid re-entrance
return;
}
final ChannelOutboundBuffer outboundBuffer = this.outboundBuffer;
if (outboundBuffer == null || outboundBuffer.isEmpty()) {
return;
}
inFlush0 = true;
// Mark all pending write requests as failure if the channel is inactive.
if (!isActive()) {
try {
if (isOpen()) {
outboundBuffer.failFlushed(FLUSH0_NOT_YET_CONNECTED_EXCEPTION, true);
} else {
// Do not trigger channelWritabilityChanged because the channel is closed already.
outboundBuffer.failFlushed(FLUSH0_CLOSED_CHANNEL_EXCEPTION, false);
}
} finally {
inFlush0 = false;
}
return;
}
try {
doWrite(outboundBuffer);
} catch (Throwable t) {
if (t instanceof IOException && config().isAutoClose()) {
/**
* Just call {@link #close(ChannelPromise, Throwable, boolean)} here which will take care of
* failing all flushed messages and also ensure the actual close of the underlying transport
* will happen before the promises are notified.
*
* This is needed as otherwise {@link #isActive()} , {@link #isOpen()} and {@link #isWritable()}
* may still return {@code true} even if the channel should be closed as result of the exception.
*/
close(voidPromise(), t, FLUSH0_CLOSED_CHANNEL_EXCEPTION, false);
} else {
outboundBuffer.failFlushed(t, true);
}
} finally {
inFlush0 = false;
}
}
@Override
public final ChannelPromise voidPromise() {
assertEventLoop();
return unsafeVoidPromise;
}
@Deprecated
protected final boolean ensureOpen(ChannelPromise promise) {
if (isOpen()) {
return true;
}
safeSetFailure(promise, ENSURE_OPEN_CLOSED_CHANNEL_EXCEPTION);
return false;
}
/**
* Marks the specified {@code promise} as success. If the {@code promise} is done already, log a message.
*/
protected final void safeSetSuccess(ChannelPromise promise) {
if (!(promise instanceof VoidChannelPromise) && !promise.trySuccess()) {
logger.warn("Failed to mark a promise as success because it is done already: {}", promise);
}
}
/**
* Marks the specified {@code promise} as failure. If the {@code promise} is done already, log a message.
*/
protected final void safeSetFailure(ChannelPromise promise, Throwable cause) {
if (!(promise instanceof VoidChannelPromise) && !promise.tryFailure(cause)) {
logger.warn("Failed to mark a promise as failure because it's done already: {}", promise, cause);
}
}
protected final void closeIfClosed() {
if (isOpen()) {
return;
}
close(voidPromise());
}
private void invokeLater(Runnable task) {
try {
// This method is used by outbound operation implementations to trigger an inbound event later.
// They do not trigger an inbound event immediately because an outbound operation might have been
// triggered by another inbound event handler method. If fired immediately, the call stack
// will look like this for example:
//
// handlerA.inboundBufferUpdated() - (1) an inbound handler method closes a connection.
// -> handlerA.ctx.close()
// -> channel.unsafe.close()
// -> handlerA.channelInactive() - (2) another inbound handler method called while in (1) yet
//
// which means the execution of two inbound handler methods of the same handler overlap undesirably.
eventLoop().execute(task);
} catch (RejectedExecutionException e) {
logger.warn("Can't invoke task later as EventLoop rejected it", e);
}
}
/**
* Appends the remote address to the message of the exceptions caused by connection attempt failure.
*/
protected final Throwable annotateConnectException(Throwable cause, SocketAddress remoteAddress) {
if (cause instanceof ConnectException) {
Throwable newT = new ConnectException(cause.getMessage() + ": " + remoteAddress);
newT.setStackTrace(cause.getStackTrace());
cause = newT;
} else if (cause instanceof NoRouteToHostException) {
Throwable newT = new NoRouteToHostException(cause.getMessage() + ": " + remoteAddress);
newT.setStackTrace(cause.getStackTrace());
cause = newT;
} else if (cause instanceof SocketException) {
Throwable newT = new SocketException(cause.getMessage() + ": " + remoteAddress);
newT.setStackTrace(cause.getStackTrace());
cause = newT;
}
return cause;
}
/**
* Prepares to close the {@link Channel}. If this method returns an {@link Executor}, the
* caller must call the {@link Executor#execute(Runnable)} method with a task that calls
* {@link #doClose()} on the returned {@link Executor}. If this method returns {@code null},
* {@link #doClose()} must be called from the caller thread. (i.e. {@link EventLoop})
*/
protected Executor prepareToClose() {
return null;
}
}
/**
* Return {@code true} if the given {@link EventLoop} is compatible with this instance.
*/
protected abstract boolean isCompatible(EventLoop loop);
/**
* Returns the {@link SocketAddress} which is bound locally.
*/
protected abstract SocketAddress localAddress0();
/**
* Return the {@link SocketAddress} which the {@link Channel} is connected to.
*/
protected abstract SocketAddress remoteAddress0();
/**
* Is called after the {@link Channel} is registered with its {@link EventLoop} as part of the register process.
*
* Sub-classes may override this method
*/
protected void doRegister() throws Exception {
// NOOP
}
/**
* Bind the {@link Channel} to the {@link SocketAddress}
*/
protected abstract void doBind(SocketAddress localAddress) throws Exception;
/**
* Disconnect this {@link Channel} from its remote peer
*/
protected abstract void doDisconnect() throws Exception;
/**
* Close the {@link Channel}
*/
protected abstract void doClose() throws Exception;
/**
* Deregister the {@link Channel} from its {@link EventLoop}.
*
* Sub-classes may override this method
*/
protected void doDeregister() throws Exception {
// NOOP
}
/**
* Schedule a read operation.
*/
protected abstract void doBeginRead() throws Exception;
/**
* Flush the content of the given buffer to the remote peer.
*/
protected abstract void doWrite(ChannelOutboundBuffer in) throws Exception;
/**
* Invoked when a new message is added to a {@link ChannelOutboundBuffer} of this {@link AbstractChannel}, so that
* the {@link Channel} implementation converts the message to another. (e.g. heap buffer -> direct buffer)
*/
protected Object filterOutboundMessage(Object msg) throws Exception {
return msg;
}
static final class CloseFuture extends DefaultChannelPromise {
CloseFuture(AbstractChannel ch) {
super(ch);
}
@Override
public ChannelPromise setSuccess() {
throw new IllegalStateException();
}
@Override
public ChannelPromise setFailure(Throwable cause) {
throw new IllegalStateException();
}
@Override
public boolean trySuccess() {
throw new IllegalStateException();
}
@Override
public boolean tryFailure(Throwable cause) {
throw new IllegalStateException();
}
boolean setClosed() {
return super.trySuccess();
}
}
}
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