AbstractIoAcceptor类继承自AbstractIoService基类，并实现了IoAcceptor接口，它主要的成员变量是本地绑定地址。
private final List<SocketAddress> defaultLocalAddresses =
new ArrayList<SocketAddress>();
private final List<SocketAddress> unmodifiableDefaultLocalAddresses =
Collections.unmodifiableList(defaultLocalAddresses);
private final Set<SocketAddress> boundAddresses =
new HashSet<SocketAddress>();
在调用bind或unbind方法时需要先获取绑定锁bindLock，具体的绑定操作还是在bind0这个方法中实现的。一旦绑定成功后，就会向服务监听者发出服务激活的事件(ServiceActivated),同理，解除绑定也是在unbind0这个方法中具体实现的。一旦解除绑定成功后，就会向服务监听者发出服务激活的事件(ServiceDeActivated)。
AbstractIoConnector类继承自AbstractIoService基类，并实现了IoConnect接口,连接超时检查间隔时间默认是50毫秒，超时时间默认为1分钟，用户可以自行配置。此类中重要的方法就是connect方法，其中调用了具体的连接逻辑实现connect0,
protected abstract ConnectFuture connect0(SocketAddress remoteAddress,
SocketAddress localAddress, IoSessionInitializer<? extends ConnectFuture> sessionInitializer);
AbstractIoConnector在AbstractIoService的基础上，在会话初始化结束时增加了一个功能，就是加入了一个监听者，当连接请求被取消时立即结束此会话。
protected final void finishSessionInitialization0(
final IoSession session, IoFuture future) {
// In case that ConnectFuture.cancel() is invoked before
// setSession() is invoked, add a listener that closes the
// connection immediately on cancellation.
future.addListener(new IoFutureListener<ConnectFuture>() {
public void operationComplete(ConnectFuture future) {
if (future.isCanceled()) {
session.close();
}
}
});
}下面再来看一个IoProcessor接口的基本实现类SimpleIoProcessorPool，它的泛型参数是AbstractIoSession的子类，表示此Processor管理的具体会话类型。并且这个类还实现了池化，它会将多个IoSession分布到多个IoProcessor上去管理。下面是文档中给出的一个示例：
// Create a shared pool.
SimpleIoProcessorPool<NioSession> pool =
new SimpleIoProcessorPool<NioSession>(NioProcessor.class, 16);
// Create two services that share the same pool.
SocketAcceptor acceptor = new NioSocketAcceptor(pool);
SocketConnector connector = new NioSocketConnector(pool);
// Release related resources.
connector.dispose();
acceptor.dispose();
pool.dispose();与Processor池有关的包括如下这些成员变量：
private static final int DEFAULT_SIZE = Runtime.getRuntime().availableProcessors() + 1;//处理池大小，默认是处理器数+1, 便于多核分布处理
private final IoProcessor<T>[] pool;//IoProcessor池
private final AtomicInteger processorDistributor = new AtomicInteger();Processor池的构造过程,其中有三种构造函数供选择来构造一个Processor ：
1.带参数 ExecutorService 的构造函数.
2.带参数为 Executor的构造函数.
3.默认构造函数
pool = new IoProcessor[size];//构建池
boolean success = false;
try {
for (int i = 0; i < pool.length; i ++) {
IoProcessor<T> processor = null;
//有三种构造函数供选择来构造一个Processor
try {
try {
processor = processorType.getConstructor(ExecutorService.class).newInstance(executor);
} catch (NoSuchMethodException e) {
// To the next step
}
if (processor == null) {
try {
processor = processorType.getConstructor(Executor.class).newInstance(executor);
} catch (NoSuchMethodException e) {
// To the next step
}
}
if (processor == null) {
try {
processor = processorType.getConstructor().newInstance();
} catch (NoSuchMethodException e) {
// To the next step
}
}
} catch (RuntimeException e) {
throw e;
} catch (Exception e) {
throw new RuntimeIoException(
"Failed to create a new instance of " + processorType.getName(), e);
}
pool[i] = processor;
}
success = true;
} finally {
if (!success) {
dispose();
}
}从Processor池中分配一个processor的过程，注意一个processor是可以同时管理多个session的。
private IoProcessor<T> getProcessor(T session)
{//返回session所在的processor，若没分配，则为之分配一个
IoProcessor<T> p = (IoProcessor<T>) session.getAttribute(PROCESSOR);//看session的属性中是否保存对应的Processor
if (p == null)
{//还没为此session分配processor
p = nextProcessor();//从池中取一个processor
IoProcessor<T> oldp =
(IoProcessor<T>) session.setAttributeIfAbsent(PROCESSOR, p);
if (oldp != null)
{//原来的processor
p = oldp;
}
}
return p;
}
private IoProcessor<T> nextProcessor()
{//从池中分配一个Processor
checkDisposal();
return pool[Math.abs(processorDistributor.getAndIncrement()) % pool.length];
}
