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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:
*
* 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 org.jboss.netty.channel;
import org.jboss.netty.logging.InternalLogger;
import org.jboss.netty.logging.InternalLoggerFactory;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.concurrent.RejectedExecutionException;
/**
* The default {@link ChannelPipeline} implementation. It is recommended
* to use {@link Channels#pipeline()} to create a new {@link ChannelPipeline}
* instance rather than calling the constructor directly.
*/
public class DefaultChannelPipeline implements ChannelPipeline {
static final InternalLogger logger = InternalLoggerFactory.getInstance(DefaultChannelPipeline.class);
static final ChannelSink discardingSink = new DiscardingChannelSink();
private volatile Channel channel;
private volatile ChannelSink sink;
private volatile DefaultChannelHandlerContext head;
private volatile DefaultChannelHandlerContext tail;
private final Map name2ctx =
new HashMap(4);
public Channel getChannel() {
return channel;
}
public ChannelSink getSink() {
ChannelSink sink = this.sink;
if (sink == null) {
return discardingSink;
}
return sink;
}
public void attach(Channel channel, ChannelSink sink) {
if (channel == null) {
throw new NullPointerException("channel");
}
if (sink == null) {
throw new NullPointerException("sink");
}
if (this.channel != null || this.sink != null) {
throw new IllegalStateException("attached already");
}
this.channel = channel;
this.sink = sink;
}
public boolean isAttached() {
return sink != null;
}
public synchronized void addFirst(String name, ChannelHandler handler) {
if (name2ctx.isEmpty()) {
init(name, handler);
} else {
checkDuplicateName(name);
DefaultChannelHandlerContext oldHead = head;
DefaultChannelHandlerContext newHead = new DefaultChannelHandlerContext(null, oldHead, name, handler);
callBeforeAdd(newHead);
oldHead.prev = newHead;
head = newHead;
name2ctx.put(name, newHead);
callAfterAdd(newHead);
}
}
public synchronized void addLast(String name, ChannelHandler handler) {
if (name2ctx.isEmpty()) {
init(name, handler);
} else {
checkDuplicateName(name);
DefaultChannelHandlerContext oldTail = tail;
DefaultChannelHandlerContext newTail = new DefaultChannelHandlerContext(oldTail, null, name, handler);
callBeforeAdd(newTail);
oldTail.next = newTail;
tail = newTail;
name2ctx.put(name, newTail);
callAfterAdd(newTail);
}
}
public synchronized void addBefore(String baseName, String name, ChannelHandler handler) {
DefaultChannelHandlerContext ctx = getContextOrDie(baseName);
if (ctx == head) {
addFirst(name, handler);
} else {
checkDuplicateName(name);
DefaultChannelHandlerContext newCtx = new DefaultChannelHandlerContext(ctx.prev, ctx, name, handler);
callBeforeAdd(newCtx);
ctx.prev.next = newCtx;
ctx.prev = newCtx;
name2ctx.put(name, newCtx);
callAfterAdd(newCtx);
}
}
public synchronized void addAfter(String baseName, String name, ChannelHandler handler) {
DefaultChannelHandlerContext ctx = getContextOrDie(baseName);
if (ctx == tail) {
addLast(name, handler);
} else {
checkDuplicateName(name);
DefaultChannelHandlerContext newCtx = new DefaultChannelHandlerContext(ctx, ctx.next, name, handler);
callBeforeAdd(newCtx);
ctx.next.prev = newCtx;
ctx.next = newCtx;
name2ctx.put(name, newCtx);
callAfterAdd(newCtx);
}
}
public synchronized void remove(ChannelHandler handler) {
remove(getContextOrDie(handler));
}
public synchronized ChannelHandler remove(String name) {
return remove(getContextOrDie(name)).getHandler();
}
@SuppressWarnings("unchecked")
public synchronized T remove(Class handlerType) {
return (T) remove(getContextOrDie(handlerType)).getHandler();
}
private DefaultChannelHandlerContext remove(DefaultChannelHandlerContext ctx) {
if (head == tail) {
callBeforeRemove(ctx);
head = tail = null;
name2ctx.clear();
callAfterRemove(ctx);
} else if (ctx == head) {
removeFirst();
} else if (ctx == tail) {
removeLast();
} else {
callBeforeRemove(ctx);
DefaultChannelHandlerContext prev = ctx.prev;
DefaultChannelHandlerContext next = ctx.next;
prev.next = next;
next.prev = prev;
name2ctx.remove(ctx.getName());
callAfterRemove(ctx);
}
return ctx;
}
public synchronized ChannelHandler removeFirst() {
if (name2ctx.isEmpty()) {
throw new NoSuchElementException();
}
DefaultChannelHandlerContext oldHead = head;
if (oldHead == null) {
throw new NoSuchElementException();
}
callBeforeRemove(oldHead);
if (oldHead.next == null) {
head = tail = null;
name2ctx.clear();
} else {
oldHead.next.prev = null;
head = oldHead.next;
name2ctx.remove(oldHead.getName());
}
callAfterRemove(oldHead);
return oldHead.getHandler();
}
public synchronized ChannelHandler removeLast() {
if (name2ctx.isEmpty()) {
throw new NoSuchElementException();
}
DefaultChannelHandlerContext oldTail = tail;
if (oldTail == null) {
throw new NoSuchElementException();
}
callBeforeRemove(oldTail);
if (oldTail.prev == null) {
head = tail = null;
name2ctx.clear();
} else {
oldTail.prev.next = null;
tail = oldTail.prev;
name2ctx.remove(oldTail.getName());
}
callAfterRemove(oldTail);
return oldTail.getHandler();
}
public synchronized void replace(ChannelHandler oldHandler, String newName, ChannelHandler newHandler) {
replace(getContextOrDie(oldHandler), newName, newHandler);
}
public synchronized ChannelHandler replace(String oldName, String newName, ChannelHandler newHandler) {
return replace(getContextOrDie(oldName), newName, newHandler);
}
@SuppressWarnings("unchecked")
public synchronized T replace(
Class oldHandlerType, String newName, ChannelHandler newHandler) {
return (T) replace(getContextOrDie(oldHandlerType), newName, newHandler);
}
private ChannelHandler replace(DefaultChannelHandlerContext ctx, String newName, ChannelHandler newHandler) {
if (ctx == head) {
removeFirst();
addFirst(newName, newHandler);
} else if (ctx == tail) {
removeLast();
addLast(newName, newHandler);
} else {
boolean sameName = ctx.getName().equals(newName);
if (!sameName) {
checkDuplicateName(newName);
}
DefaultChannelHandlerContext prev = ctx.prev;
DefaultChannelHandlerContext next = ctx.next;
DefaultChannelHandlerContext newCtx = new DefaultChannelHandlerContext(prev, next, newName, newHandler);
callBeforeRemove(ctx);
callBeforeAdd(newCtx);
prev.next = newCtx;
next.prev = newCtx;
if (!sameName) {
name2ctx.remove(ctx.getName());
}
name2ctx.put(newName, newCtx);
ChannelHandlerLifeCycleException removeException = null;
ChannelHandlerLifeCycleException addException = null;
boolean removed = false;
try {
callAfterRemove(ctx);
removed = true;
} catch (ChannelHandlerLifeCycleException e) {
removeException = e;
}
boolean added = false;
try {
callAfterAdd(newCtx);
added = true;
} catch (ChannelHandlerLifeCycleException e) {
addException = e;
}
if (!removed && !added) {
logger.warn(removeException.getMessage(), removeException);
logger.warn(addException.getMessage(), addException);
throw new ChannelHandlerLifeCycleException(
"Both " + ctx.getHandler().getClass().getName() +
".afterRemove() and " + newCtx.getHandler().getClass().getName() +
".afterAdd() failed; see logs.");
} else if (!removed) {
throw removeException;
} else if (!added) {
throw addException;
}
}
return ctx.getHandler();
}
private static void callBeforeAdd(ChannelHandlerContext ctx) {
if (!(ctx.getHandler() instanceof LifeCycleAwareChannelHandler)) {
return;
}
LifeCycleAwareChannelHandler h =
(LifeCycleAwareChannelHandler) ctx.getHandler();
try {
h.beforeAdd(ctx);
} catch (Throwable t) {
throw new ChannelHandlerLifeCycleException(
h.getClass().getName() +
".beforeAdd() has thrown an exception; not adding.", t);
}
}
private void callAfterAdd(ChannelHandlerContext ctx) {
if (!(ctx.getHandler() instanceof LifeCycleAwareChannelHandler)) {
return;
}
LifeCycleAwareChannelHandler h =
(LifeCycleAwareChannelHandler) ctx.getHandler();
try {
h.afterAdd(ctx);
} catch (Throwable t) {
boolean removed = false;
try {
remove((DefaultChannelHandlerContext) ctx);
removed = true;
} catch (Throwable t2) {
if (logger.isWarnEnabled()) {
logger.warn("Failed to remove a handler: " + ctx.getName(), t2);
}
}
if (removed) {
throw new ChannelHandlerLifeCycleException(
h.getClass().getName() +
".afterAdd() has thrown an exception; removed.", t);
} else {
throw new ChannelHandlerLifeCycleException(
h.getClass().getName() +
".afterAdd() has thrown an exception; also failed to remove.", t);
}
}
}
private static void callBeforeRemove(ChannelHandlerContext ctx) {
if (!(ctx.getHandler() instanceof LifeCycleAwareChannelHandler)) {
return;
}
LifeCycleAwareChannelHandler h =
(LifeCycleAwareChannelHandler) ctx.getHandler();
try {
h.beforeRemove(ctx);
} catch (Throwable t) {
throw new ChannelHandlerLifeCycleException(
h.getClass().getName() +
".beforeRemove() has thrown an exception; not removing.", t);
}
}
private static void callAfterRemove(ChannelHandlerContext ctx) {
if (!(ctx.getHandler() instanceof LifeCycleAwareChannelHandler)) {
return;
}
LifeCycleAwareChannelHandler h =
(LifeCycleAwareChannelHandler) ctx.getHandler();
try {
h.afterRemove(ctx);
} catch (Throwable t) {
throw new ChannelHandlerLifeCycleException(
h.getClass().getName() +
".afterRemove() has thrown an exception.", t);
}
}
public synchronized ChannelHandler getFirst() {
DefaultChannelHandlerContext head = this.head;
if (head == null) {
return null;
}
return head.getHandler();
}
public synchronized ChannelHandler getLast() {
DefaultChannelHandlerContext tail = this.tail;
if (tail == null) {
return null;
}
return tail.getHandler();
}
public synchronized ChannelHandler get(String name) {
DefaultChannelHandlerContext ctx = name2ctx.get(name);
if (ctx == null) {
return null;
} else {
return ctx.getHandler();
}
}
public synchronized T get(Class handlerType) {
ChannelHandlerContext ctx = getContext(handlerType);
if (ctx == null) {
return null;
} else {
@SuppressWarnings("unchecked")
T handler = (T) ctx.getHandler();
return handler;
}
}
public synchronized ChannelHandlerContext getContext(String name) {
if (name == null) {
throw new NullPointerException("name");
}
return name2ctx.get(name);
}
public synchronized ChannelHandlerContext getContext(ChannelHandler handler) {
if (handler == null) {
throw new NullPointerException("handler");
}
if (name2ctx.isEmpty()) {
return null;
}
DefaultChannelHandlerContext ctx = head;
for (;;) {
if (ctx.getHandler() == handler) {
return ctx;
}
ctx = ctx.next;
if (ctx == null) {
break;
}
}
return null;
}
public synchronized ChannelHandlerContext getContext(
Class handlerType) {
if (handlerType == null) {
throw new NullPointerException("handlerType");
}
if (name2ctx.isEmpty()) {
return null;
}
DefaultChannelHandlerContext ctx = head;
for (;;) {
if (handlerType.isAssignableFrom(ctx.getHandler().getClass())) {
return ctx;
}
ctx = ctx.next;
if (ctx == null) {
break;
}
}
return null;
}
public List getNames() {
List list = new ArrayList();
if (name2ctx.isEmpty()) {
return list;
}
DefaultChannelHandlerContext ctx = head;
for (;;) {
list.add(ctx.getName());
ctx = ctx.next;
if (ctx == null) {
break;
}
}
return list;
}
public Map toMap() {
Map map = new LinkedHashMap();
if (name2ctx.isEmpty()) {
return map;
}
DefaultChannelHandlerContext ctx = head;
for (;;) {
map.put(ctx.getName(), ctx.getHandler());
ctx = ctx.next;
if (ctx == null) {
break;
}
}
return map;
}
/**
* Returns the {@link String} representation of this pipeline.
*/
@Override
public String toString() {
StringBuilder buf = new StringBuilder();
buf.append(getClass().getSimpleName());
buf.append('{');
DefaultChannelHandlerContext ctx = head;
if (ctx != null) {
for (;;) {
buf.append('(');
buf.append(ctx.getName());
buf.append(" = ");
buf.append(ctx.getHandler().getClass().getName());
buf.append(')');
ctx = ctx.next;
if (ctx == null) {
break;
}
buf.append(", ");
}
}
buf.append('}');
return buf.toString();
}
public void sendUpstream(ChannelEvent e) {
DefaultChannelHandlerContext head = getActualUpstreamContext(this.head);
if (head == null) {
if (logger.isWarnEnabled()) {
logger.warn(
"The pipeline contains no upstream handlers; discarding: " + e);
}
return;
}
sendUpstream(head, e);
}
void sendUpstream(DefaultChannelHandlerContext ctx, ChannelEvent e) {
try {
((ChannelUpstreamHandler) ctx.getHandler()).handleUpstream(ctx, e);
} catch (Throwable t) {
notifyHandlerException(e, t);
}
}
public void sendDownstream(ChannelEvent e) {
DefaultChannelHandlerContext tail = getActualDownstreamContext(this.tail);
if (tail == null) {
try {
getSink().eventSunk(this, e);
return;
} catch (Throwable t) {
notifyHandlerException(e, t);
return;
}
}
sendDownstream(tail, e);
}
void sendDownstream(DefaultChannelHandlerContext ctx, ChannelEvent e) {
if (e instanceof UpstreamMessageEvent) {
throw new IllegalArgumentException("cannot send an upstream event to downstream");
}
try {
((ChannelDownstreamHandler) ctx.getHandler()).handleDownstream(ctx, e);
} catch (Throwable t) {
// Unlike an upstream event, a downstream event usually has an
// incomplete future which is supposed to be updated by ChannelSink.
// However, if an exception is raised before the event reaches at
// ChannelSink, the future is not going to be updated, so we update
// here.
e.getFuture().setFailure(t);
notifyHandlerException(e, t);
}
}
private DefaultChannelHandlerContext getActualUpstreamContext(DefaultChannelHandlerContext ctx) {
if (ctx == null) {
return null;
}
DefaultChannelHandlerContext realCtx = ctx;
while (!realCtx.canHandleUpstream()) {
realCtx = realCtx.next;
if (realCtx == null) {
return null;
}
}
return realCtx;
}
private DefaultChannelHandlerContext getActualDownstreamContext(DefaultChannelHandlerContext ctx) {
if (ctx == null) {
return null;
}
DefaultChannelHandlerContext realCtx = ctx;
while (!realCtx.canHandleDownstream()) {
realCtx = realCtx.prev;
if (realCtx == null) {
return null;
}
}
return realCtx;
}
public ChannelFuture execute(Runnable task) {
return getSink().execute(this, task);
}
protected void notifyHandlerException(ChannelEvent e, Throwable t) {
if (e instanceof ExceptionEvent) {
if (logger.isWarnEnabled()) {
logger.warn(
"An exception was thrown by a user handler " +
"while handling an exception event (" + e + ')', t);
}
return;
}
ChannelPipelineException pe;
if (t instanceof ChannelPipelineException) {
pe = (ChannelPipelineException) t;
} else {
pe = new ChannelPipelineException(t);
}
try {
sink.exceptionCaught(this, e, pe);
} catch (Exception e1) {
if (logger.isWarnEnabled()) {
logger.warn("An exception was thrown by an exception handler.", e1);
}
}
}
private void init(String name, ChannelHandler handler) {
DefaultChannelHandlerContext ctx = new DefaultChannelHandlerContext(null, null, name, handler);
callBeforeAdd(ctx);
head = tail = ctx;
name2ctx.clear();
name2ctx.put(name, ctx);
callAfterAdd(ctx);
}
private void checkDuplicateName(String name) {
if (name2ctx.containsKey(name)) {
throw new IllegalArgumentException("Duplicate handler name: " + name);
}
}
private DefaultChannelHandlerContext getContextOrDie(String name) {
DefaultChannelHandlerContext ctx = (DefaultChannelHandlerContext) getContext(name);
if (ctx == null) {
throw new NoSuchElementException(name);
} else {
return ctx;
}
}
private DefaultChannelHandlerContext getContextOrDie(ChannelHandler handler) {
DefaultChannelHandlerContext ctx = (DefaultChannelHandlerContext) getContext(handler);
if (ctx == null) {
throw new NoSuchElementException(handler.getClass().getName());
} else {
return ctx;
}
}
private DefaultChannelHandlerContext getContextOrDie(Class handlerType) {
DefaultChannelHandlerContext ctx = (DefaultChannelHandlerContext) getContext(handlerType);
if (ctx == null) {
throw new NoSuchElementException(handlerType.getName());
} else {
return ctx;
}
}
private final class DefaultChannelHandlerContext implements ChannelHandlerContext {
volatile DefaultChannelHandlerContext next;
volatile DefaultChannelHandlerContext prev;
private final String name;
private final ChannelHandler handler;
private final boolean canHandleUpstream;
private final boolean canHandleDownstream;
private volatile Object attachment;
DefaultChannelHandlerContext(
DefaultChannelHandlerContext prev, DefaultChannelHandlerContext next,
String name, ChannelHandler handler) {
if (name == null) {
throw new NullPointerException("name");
}
if (handler == null) {
throw new NullPointerException("handler");
}
canHandleUpstream = handler instanceof ChannelUpstreamHandler;
canHandleDownstream = handler instanceof ChannelDownstreamHandler;
if (!canHandleUpstream && !canHandleDownstream) {
throw new IllegalArgumentException(
"handler must be either " +
ChannelUpstreamHandler.class.getName() + " or " +
ChannelDownstreamHandler.class.getName() + '.');
}
this.prev = prev;
this.next = next;
this.name = name;
this.handler = handler;
}
public Channel getChannel() {
return getPipeline().getChannel();
}
public ChannelPipeline getPipeline() {
return DefaultChannelPipeline.this;
}
public boolean canHandleDownstream() {
return canHandleDownstream;
}
public boolean canHandleUpstream() {
return canHandleUpstream;
}
public ChannelHandler getHandler() {
return handler;
}
public String getName() {
return name;
}
public Object getAttachment() {
return attachment;
}
public void setAttachment(Object attachment) {
this.attachment = attachment;
}
public void sendDownstream(ChannelEvent e) {
DefaultChannelHandlerContext prev = getActualDownstreamContext(this.prev);
if (prev == null) {
try {
getSink().eventSunk(DefaultChannelPipeline.this, e);
} catch (Throwable t) {
notifyHandlerException(e, t);
}
} else {
DefaultChannelPipeline.this.sendDownstream(prev, e);
}
}
public void sendUpstream(ChannelEvent e) {
DefaultChannelHandlerContext next = getActualUpstreamContext(this.next);
if (next != null) {
DefaultChannelPipeline.this.sendUpstream(next, e);
}
}
}
private static final class DiscardingChannelSink implements ChannelSink {
DiscardingChannelSink() {
}
public void eventSunk(ChannelPipeline pipeline, ChannelEvent e) {
if (logger.isWarnEnabled()) {
logger.warn("Not attached yet; discarding: " + e);
}
}
public void exceptionCaught(ChannelPipeline pipeline,
ChannelEvent e, ChannelPipelineException cause) throws Exception {
throw cause;
}
public ChannelFuture execute(ChannelPipeline pipeline, Runnable task) {
if (logger.isWarnEnabled()) {
logger.warn("Not attached yet; rejecting: " + task);
}
return Channels.failedFuture(pipeline.getChannel(), new RejectedExecutionException("Not attached yet"));
}
}
}