package org.jboss.netty.channel;
import org.jboss.netty.util.internal.ConcurrentHashMap;
import java.net.SocketAddress;
import java.util.Random;
import java.util.concurrent.ConcurrentMap;
/**
* A skeletal Channel implementation.
*/
public abstract class AbstractChannel implements
org.jboss.netty.channel.Channel {
//ά��Channel��Ӧ��ID
static final ConcurrentMap<Integer, Channel> allChannels = new ConcurrentHashMap<Integer, Channel>();
private static final Random random = new Random();
private static Integer allocateId(Channel channel) {
Integer id = random.nextInt();
for (;;) {
// ѭ��ֱ���õ�һ��Ψһ��ID.
// It should be found in one loop practically.
if (allChannels.putIfAbsent(id, channel) == null) {
// Successfully acquired.
return id;
} else {
// Taken by other channel at almost the same moment.
id = id.intValue() + 1;
}
}
}
private final Integer id;
private final Channel parent; //
private final ChannelFactory factory;
private final ChannelPipeline pipeline;
//
private final ChannelFuture succeededFuture = new SucceededChannelFuture(
this);
private final ChannelCloseFuture closeFuture = new ChannelCloseFuture();
private volatile int interestOps = OP_READ;
/** Cache for the string representation of this channel */
private boolean strValConnected;
private String strVal;
private volatile Object attachment;
/**
* ����ʵ����ע����������ĺ��壬�ر���ChannelSink
*
* @param parent
* the parent of this channel. {@code null} if there's no parent.
* @param factory
* the factory which created this channel
* @param pipeline
* the pipeline which is going to be attached to this channel
* @param sink
* the sink which will receive downstream events from the
* pipeline and send upstream events to the pipeline
*/
protected AbstractChannel(Channel parent, ChannelFactory factory,
ChannelPipeline pipeline, ChannelSink sink) {
this.parent = parent;
this.factory = factory;
this.pipeline = pipeline;
id = allocateId(this);
pipeline.attach(this, sink);
}
// (Internal use only) Creates a new temporary instance with the specified
// ID.
protected AbstractChannel(Integer id, Channel parent,
ChannelFactory factory, ChannelPipeline pipeline, ChannelSink sink) {
this.id = id;
this.parent = parent;
this.factory = factory;
this.pipeline = pipeline;
pipeline.attach(this, sink);
}
public final Integer getId() {
return id;
}
public Channel getParent() {
return parent;
}
public ChannelFactory getFactory() {
return factory;
}
public ChannelPipeline getPipeline() {
return pipeline;
}
/**
* Returns the cached SucceededChannelFuture instance.
*/
protected ChannelFuture getSucceededFuture() {
return succeededFuture;
}
/**
* Returns the FailedChannelFuture whose cause is an
* UnsupportedOperationException.
*/
protected ChannelFuture getUnsupportedOperationFuture() {
return new FailedChannelFuture(this,
new UnsupportedOperationException());
}
/**
* Returns the ID of this channel.
*/
@Override
public final int hashCode() {
return id;
}
// �������
@Override
public final boolean equals(Object o) {
return this == o;
}
// ��ID���Ƚ�
public final int compareTo(Channel o) {
return getId().compareTo(o.getId());
}
public boolean isOpen() {
return !closeFuture.isDone();
}
/**
* Marks this channel as closed. This method is intended to be called by an
* internal component - please do not call it unless you know what you are
* doing.
*
* @return {@code true} if and only if this channel was not marked as closed
* yet
*/
protected boolean setClosed() {
// Deallocate the current channel's ID from allChannels so that other
// new channels can use it.
allChannels.remove(id);
return closeFuture.setClosed();
}
// ���涼�ǵ��ø���������������ֵĻ���������
public ChannelFuture bind(SocketAddress localAddress) {
return Channels.bind(this, localAddress);
}
public ChannelFuture unbind() {
return Channels.unbind(this);
}
public ChannelFuture close() {
ChannelFuture returnedCloseFuture = Channels.close(this);
assert closeFuture == returnedCloseFuture;
return closeFuture;
}
public ChannelFuture getCloseFuture() {
return closeFuture;
}
public ChannelFuture connect(SocketAddress remoteAddress) {
return Channels.connect(this, remoteAddress);
}
public ChannelFuture disconnect() {
return Channels.disconnect(this);
}
public int getInterestOps() {
return interestOps;
}
public ChannelFuture setInterestOps(int interestOps) {
return Channels.setInterestOps(this, interestOps);
}
/**
* Sets the interestOps property of this channel immediately. This method is
* intended to be called by an internal component - please do not call it
* unless you know what you are doing. ֱ�Ӹı�ij�Ա������������ͨ�����������뵽���һ��handler
*/
protected void setInterestOpsNow(int interestOps) {
this.interestOps = interestOps;
}
public boolean isReadable() {
return (getInterestOps() & OP_READ) != 0;
}
public boolean isWritable() {
return (getInterestOps() & OP_WRITE) == 0;
}
public ChannelFuture setReadable(boolean readable) {
if (readable) {
return setInterestOps(getInterestOps() | OP_READ);
} else {
return setInterestOps(getInterestOps() & ~OP_READ);
}
}
public ChannelFuture write(Object message) {
return Channels.write(this, message);
}
public ChannelFuture write(Object message, SocketAddress remoteAddress) {
return Channels.write(this, message, remoteAddress);
}
public Object getAttachment() {
return attachment;
}
public void setAttachment(Object attachment) {
this.attachment = attachment;
}
/**
* Returns the String representation of this channel. The returned string
* contains the ID, local address, and remote address of this channel for
* easier identification.
*/
@Override
public String toString() {
boolean connected = isConnected();
if (strValConnected == connected && strVal != null) {
return strVal;
}
StringBuilder buf = new StringBuilder(128);
buf.append("[id: 0x");
buf.append(getIdString());
SocketAddress localAddress = getLocalAddress();
SocketAddress remoteAddress = getRemoteAddress();
if (remoteAddress != null) {
buf.append(", ");
if (getParent() == null) {
buf.append(localAddress);
buf.append(connected ? " => " : " :> ");
buf.append(remoteAddress);
} else {
buf.append(remoteAddress);
buf.append(connected ? " => " : " :> ");
buf.append(localAddress);
}
} else if (localAddress != null) {
buf.append(", ");
buf.append(localAddress);
}
buf.append(']');
String strVal = buf.toString();
this.strVal = strVal;
strValConnected = connected;
return strVal;
}
private String getIdString() {
String answer = Integer.toHexString(id.intValue());
switch (answer.length()) {
case 0:
answer = "00000000";
break;
case 1:
answer = "0000000" + answer;
break;
case 2:
answer = "000000" + answer;
break;
case 3:
answer = "00000" + answer;
break;
case 4:
answer = "0000" + answer;
break;
case 5:
answer = "000" + answer;
break;
case 6:
answer = "00" + answer;
break;
case 7:
answer = '0' + answer;
break;
}
return answer;
}
private final class ChannelCloseFuture extends DefaultChannelFuture {
public ChannelCloseFuture() {
super(AbstractChannel.this, false);
}
@Override
public boolean setSuccess() {
// User is not supposed to call this method - ignore silently.
return false;
}
@Override
public boolean setFailure(Throwable cause) {
// User is not supposed to call this method - ignore silently.
return false;
}
boolean setClosed() {
return super.setSuccess();
}
}
}