com.facebook.presto.jdbc.internal.jetty.io.AbstractConnection Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package com.facebook.presto.jdbc.internal.jetty.io;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.Executor;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicReference;
import com.facebook.presto.jdbc.internal.jetty.util.Callback;
import com.facebook.presto.jdbc.internal.jetty.util.log.Log;
import com.facebook.presto.jdbc.internal.jetty.util.log.Logger;
import com.facebook.presto.jdbc.internal.jetty.util.thread.NonBlockingThread;
/**
* A convenience base implementation of {@link Connection}.
* This class uses the capabilities of the {@link EndPoint} API to provide a
* more traditional style of async reading. A call to {@link #fillInterested()}
* will schedule a callback to {@link #onFillable()} or {@link #onFillInterestedFailed(Throwable)}
* as appropriate.
*/
public abstract class AbstractConnection implements Connection
{
private static final Logger LOG = Log.getLogger(AbstractConnection.class);
public static final boolean EXECUTE_ONFILLABLE=true;
private final List listeners = new CopyOnWriteArrayList<>();
private final AtomicReference _state = new AtomicReference<>(IDLE);
private final long _created=System.currentTimeMillis();
private final EndPoint _endPoint;
private final Executor _executor;
private final Callback _readCallback;
private final boolean _executeOnfillable;
private int _inputBufferSize=2048;
protected AbstractConnection(EndPoint endp, Executor executor)
{
this(endp,executor,EXECUTE_ONFILLABLE);
}
protected AbstractConnection(EndPoint endp, Executor executor, final boolean executeOnfillable)
{
if (executor == null)
throw new IllegalArgumentException("Executor must not be null!");
_endPoint = endp;
_executor = executor;
_readCallback = new ReadCallback();
_executeOnfillable=executeOnfillable;
_state.set(IDLE);
}
@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;
}
protected void failedCallback(final Callback callback, final Throwable x)
{
if (NonBlockingThread.isNonBlockingThread())
{
try
{
getExecutor().execute(new Runnable()
{
@Override
public void run()
{
callback.failed(x);
}
});
}
catch(RejectedExecutionException e)
{
LOG.debug(e);
callback.failed(x);
}
}
else
{
callback.failed(x);
}
}
/**
* Utility method to be called to register read interest.
* After a call to this method, {@link #onFillable()} or {@link #onFillInterestedFailed(Throwable)}
* will be called back as appropriate.
* @see #onFillable()
*/
public void fillInterested()
{
if (LOG.isDebugEnabled())
LOG.debug("fillInterested {}",this);
while(true)
{
State state=_state.get();
if (next(state,state.fillInterested()))
break;
}
}
public void fillInterested(Callback callback)
{
if (LOG.isDebugEnabled())
LOG.debug("fillInterested {}",this);
while(true)
{
State state=_state.get();
// TODO yuck
if (state instanceof FillingInterestedCallback && ((FillingInterestedCallback)state)._callback==callback)
break;
State next=new FillingInterestedCallback(callback,state);
if (next(state,next))
break;
}
}
/**
* Callback method invoked when the endpoint is ready to be read.
* @see #fillInterested()
*/
public abstract void onFillable();
/**
* Callback method invoked when the endpoint failed to be ready to be read.
* @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();
}
}
if (_endPoint.isOpen())
fillInterested();
}
/**
* Callback method invoked when the endpoint failed to be ready to be read after a timeout
* @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(), _state.get());
}
public boolean next(State state, State next)
{
if (next==null)
return true;
if(_state.compareAndSet(state,next))
{
if (LOG.isDebugEnabled())
LOG.debug("{}-->{} {}",state,next,this);
if (next!=state)
next.onEnter(AbstractConnection.this);
return true;
}
return false;
}
private static final class IdleState extends State
{
private IdleState()
{
super("IDLE");
}
@Override
State fillInterested()
{
return FILL_INTERESTED;
}
}
private static final class FillInterestedState extends State
{
private FillInterestedState()
{
super("FILL_INTERESTED");
}
@Override
public void onEnter(AbstractConnection connection)
{
connection.getEndPoint().fillInterested(connection._readCallback);
}
@Override
State fillInterested()
{
return this;
}
@Override
public State onFillable()
{
return FILLING;
}
@Override
State onFailed()
{
return IDLE;
}
}
private static final class RefillingState extends State
{
private RefillingState()
{
super("REFILLING");
}
@Override
State fillInterested()
{
return FILLING_FILL_INTERESTED;
}
@Override
public State onFilled()
{
return IDLE;
}
}
private static final class FillingFillInterestedState extends State
{
private FillingFillInterestedState(String name)
{
super(name);
}
@Override
State fillInterested()
{
return this;
}
State onFilled()
{
return FILL_INTERESTED;
}
}
private static final class FillingState extends State
{
private FillingState()
{
super("FILLING");
}
@Override
public void onEnter(AbstractConnection connection)
{
if (connection._executeOnfillable)
connection.getExecutor().execute(connection._runOnFillable);
else
connection._runOnFillable.run();
}
@Override
State fillInterested()
{
return FILLING_FILL_INTERESTED;
}
@Override
public State onFilled()
{
return IDLE;
}
}
public static class State
{
private final String _name;
State(String name)
{
_name=name;
}
@Override
public String toString()
{
return _name;
}
void onEnter(AbstractConnection connection)
{
}
State fillInterested()
{
throw new IllegalStateException(this.toString());
}
State onFillable()
{
throw new IllegalStateException(this.toString());
}
State onFilled()
{
throw new IllegalStateException(this.toString());
}
State onFailed()
{
throw new IllegalStateException(this.toString());
}
}
public static final State IDLE=new IdleState();
public static final State FILL_INTERESTED=new FillInterestedState();
public static final State FILLING=new FillingState();
public static final State REFILLING=new RefillingState();
public static final State FILLING_FILL_INTERESTED=new FillingFillInterestedState("FILLING_FILL_INTERESTED");
public class NestedState extends State
{
private final State _nested;
NestedState(State nested)
{
super("NESTED("+nested+")");
_nested=nested;
}
NestedState(String name,State nested)
{
super(name+"("+nested+")");
_nested=nested;
}
@Override
State fillInterested()
{
return new NestedState(_nested.fillInterested());
}
@Override
State onFillable()
{
return new NestedState(_nested.onFillable());
}
@Override
State onFilled()
{
return new NestedState(_nested.onFilled());
}
}
public class FillingInterestedCallback extends NestedState
{
private final Callback _callback;
FillingInterestedCallback(Callback callback,State nested)
{
super("FILLING_INTERESTED_CALLBACK",nested==FILLING?REFILLING:nested);
_callback=callback;
}
@Override
void onEnter(final AbstractConnection connection)
{
Callback callback=new Callback()
{
@Override
public void succeeded()
{
while(true)
{
State state = connection._state.get();
if (!(state instanceof NestedState))
break;
State nested=((NestedState)state)._nested;
if (connection.next(state,nested))
break;
}
_callback.succeeded();
}
@Override
public void failed(Throwable x)
{
while(true)
{
State state = connection._state.get();
if (!(state instanceof NestedState))
break;
State nested=((NestedState)state)._nested;
if (connection.next(state,nested))
break;
}
_callback.failed(x);
}
};
connection.getEndPoint().fillInterested(callback);
}
}
private final Runnable _runOnFillable = new Runnable()
{
@Override
public void run()
{
try
{
onFillable();
}
finally
{
while(true)
{
State state=_state.get();
if (next(state,state.onFilled()))
break;
}
}
}
};
private class ReadCallback implements Callback
{
@Override
public void succeeded()
{
while(true)
{
State state=_state.get();
if (next(state,state.onFillable()))
break;
}
}
@Override
public void failed(final Throwable x)
{
_executor.execute(new Runnable()
{
@Override
public void run()
{
while(true)
{
State state=_state.get();
if (next(state,state.onFailed()))
break;
}
onFillInterestedFailed(x);
}
});
}
@Override
public String toString()
{
return String.format("AC.ReadCB@%x{%s}", AbstractConnection.this.hashCode(),AbstractConnection.this);
}
};
}