Jetty9 源码初解(2)——IO之Connection
一、概述
查看Jetty-io包，清单如下：
接口类： ByteBufferPool ClientConnectionFactory Connection Connection.Listener Connection.UpgradeFrom Connection.UpgradeTo EndPoint ManagedSelector.SelectableEndPoint NetworkTrafficListener 实体类： AbstractConnection AbstractEndPoint ArrayByteBufferPool ArrayByteBufferPool.Bucket ByteArrayEndPoint ByteBufferPool.Lease ChannelEndPoint ClientConnectionFactory.Helper Connection.Listener.Adapter FillInterest IdleTimeout LeakTrackingByteBufferPool ManagedSelector MappedByteBufferPool MappedByteBufferPool.Tagged NegotiatingClientConnection NegotiatingClientConnectionFactory NetworkTrafficListener.Adapter NetworkTrafficSelectChannelEndPoint SelectChannelEndPoint SelectorManager WriteFlusher WriterOutputStream 异常类： EofException RuntimeIOException
从名字看几个主要的类可能为：Connection、ByteBufferPool、SelectorManager、EndPoint，因为其他类应该是从中延伸出来的。
二、类分析
首先看Connection接口：
public interface Connection extends Closeable
{
public void addListener(Listener listener);
public void onOpen();
/**
* <p>Callback method invoked when this {@link Connection} is closed.</p>
* <p>Creators of the connection implementation are responsible for calling this method.</p>
*/
public void onClose();
/**
* @return the {@link EndPoint} associated with this {@link Connection}
*/
public EndPoint getEndPoint();
/**
* <p>Performs a logical close of this connection.</p>
* <p>For simple connections, this may just mean to delegate the close to the associated
* {@link EndPoint} but, for example, SSL connections should write the SSL close message
* before closing the associated {@link EndPoint}.</p>
*/
@Override
public void close();
public int getMessagesIn();
public int getMessagesOut();
public long getBytesIn();
public long getBytesOut();
public long getCreatedTimeStamp();
public interface UpgradeFrom extends Connection
{
/* ------------------------------------------------------------ */
/** Take the input buffer from the connection on upgrade.
* <p>This method is used to take any unconsumed input from
* a connection during an upgrade.
* @return A buffer of unconsumed input. The caller must return the buffer
* to the bufferpool when consumed and this connection must not.
*/
ByteBuffer onUpgradeFrom();
}
public interface UpgradeTo extends Connection
{
/**
* <p>Callback method invoked when this {@link Connection} is upgraded.</p>
* <p>This must be called before {@link #onOpen()}.</p>
* @param prefilled An optional buffer that can contain prefilled data. Typically this
* results from an upgrade of one protocol to the other where the old connection has buffered
* data destined for the new connection. The new connection must take ownership of the buffer
* and is responsible for returning it to the buffer pool
*/
void onUpgradeTo(ByteBuffer prefilled);
}
/* ------------------------------------------------------------ */
/**
* <p>A Listener for connection events.</p>
* <p>Listeners can be added to a {@link Connection} to get open and close events.
* The AbstractConnectionFactory implements a pattern where objects implement
* this interface that have been added via {@link Container#addBean(Object)} to
* the Connector or ConnectionFactory are added as listeners to all new connections
* </p>
*/
public interface Listener
{
public void onOpened(Connection connection);
public void onClosed(Connection connection);
public static class Adapter implements Listener
{
@Override
public void onOpened(Connection connection)
{
}
@Override
public void onClosed(Connection connection)
{
}
}
}
}
Connection接口主要用来添加监听，并定义监听接口Listener。
再看一个实现了Connection接口的抽象类AbstractConnection：
public abstract class AbstractConnection implements Connection
{
private static final Logger LOG = Log.getLogger(AbstractConnection.class);
private final List<Listener> listeners = new CopyOnWriteArrayList<>();
private final long _created=System.currentTimeMillis();
private final EndPoint _endPoint;
private final Executor _executor;
private final Callback _readCallback;
private int _inputBufferSize=2048;
protected AbstractConnection(EndPoint endp, Executor executor)
{
if (executor == null)
throw new IllegalArgumentException("Executor must not be null!");
_endPoint = endp;
_executor = executor;
_readCallback = new ReadCallback();
}
@Override
public void addListener(Listener listener)
{
listeners.add(listener);
}
public int getInputBufferSize()
{
return _inputBufferSize;
}
public void setInputBufferSize(int inputBufferSize)
{
_inputBufferSize = inputBufferSize;
}
protected Executor getExecutor()
{
return _executor;
}
@Deprecated
public boolean isDispatchIO()
{
return false;
}
protected void failedCallback(final Callback callback, final Throwable x)
{
if (callback.isNonBlocking())
{
try
{
callback.failed(x);
}
catch (Exception e)
{
LOG.warn(e);
}
}
else
{
try
{
getExecutor().execute(new Runnable()
{
@Override
public void run()
{
try
{
callback.failed(x);
}
catch (Exception e)
{
LOG.warn(e);
}
}
});
}
catch(RejectedExecutionException e)
{
LOG.debug(e);
callback.failed(x);
}
}
}
/**
* <p>Utility method to be called to register read interest.</p>
* <p>After a call to this method, {@link #onFillable()} or {@link #onFillInterestedFailed(Throwable)}
* will be called back as appropriate.</p>
* @see #onFillable()
*/
public void fillInterested()
{
if (LOG.isDebugEnabled())
LOG.debug("fillInterested {}",this);
getEndPoint().fillInterested(_readCallback);
}
public boolean isFillInterested()
{
return getEndPoint().isFillInterested();
}
/**
* <p>Callback method invoked when the endpoint is ready to be read.</p>
* @see #fillInterested()
*/
public abstract void onFillable();
/**
* <p>Callback method invoked when the endpoint failed to be ready to be read.</p>
* @param cause the exception that caused the failure
*/
protected void onFillInterestedFailed(Throwable cause)
{
if (LOG.isDebugEnabled())
LOG.debug("{} onFillInterestedFailed {}", this, cause);
if (_endPoint.isOpen())
{
boolean close = true;
if (cause instanceof TimeoutException)
close = onReadTimeout();
if (close)
{
if (_endPoint.isOutputShutdown())
_endPoint.close();
else
{
_endPoint.shutdownOutput();
fillInterested();
}
}
}
}
/**
* <p>Callback method invoked when the endpoint failed to be ready to be read after a timeout</p>
* @return true to signal that the endpoint must be closed, false to keep the endpoint open
*/
protected boolean onReadTimeout()
{
return true;
}
@Override
public void onOpen()
{
if (LOG.isDebugEnabled())
LOG.debug("onOpen {}", this);
for (Listener listener : listeners)
listener.onOpened(this);
}
@Override
public void onClose()
{
if (LOG.isDebugEnabled())
LOG.debug("onClose {}",this);
for (Listener listener : listeners)
listener.onClosed(this);
}
@Override
public EndPoint getEndPoint()
{
return _endPoint;
}
@Override
public void close()
{
getEndPoint().close();
}
@Override
public int getMessagesIn()
{
return -1;
}
@Override
public int getMessagesOut()
{
return -1;
}
@Override
public long getBytesIn()
{
return -1;
}
@Override
public long getBytesOut()
{
return -1;
}
@Override
public long getCreatedTimeStamp()
{
return _created;
}
@Override
public String toString()
{
return String.format("%s@%x[%s]",
getClass().getSimpleName(),
hashCode(),
_endPoint);
}
private class ReadCallback implements Callback
{
@Override
public void succeeded()
{
onFillable();
}
@Override
public void failed(final Throwable x)
{
onFillInterestedFailed(x);
}
@Override
public String toString()
{
return String.format("AC.ReadCB@%x{%s}", AbstractConnection.this.hashCode(),AbstractConnection.this);
}
}
}