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/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.
*
*/
using System;
using System.Collections;
using log4net;
using Apache.Qpid.Client.Handler;
using Apache.Qpid.Client.Protocol;
using Apache.Qpid.Client.Protocol.Listener;
using Apache.Qpid.Framing;
namespace Apache.Qpid.Client.State
{
public class AMQStateManager : IAMQMethodListener
{
private static readonly ILog _logger = LogManager.GetLogger(typeof(AMQStateManager));
const bool InfoLoggingHack = true;
/// <summary>
/// The current state
/// </summary>
private AMQState _currentState;
/// <summary>
/// Maps from an AMQState instance to a Map from Class to StateTransitionHandler.
/// The class must be a subclass of AMQFrame.
/// </summary>
private readonly IDictionary _state2HandlersMap;
private ArrayList _stateListeners;
private object _syncLock;
public AMQStateManager()
{
_syncLock = new object();
_state2HandlersMap = new Hashtable();
_stateListeners = ArrayList.Synchronized(new ArrayList(5));
_currentState = AMQState.CONNECTION_NOT_STARTED;
RegisterListeners();
}
private void RegisterListeners()
{
IStateAwareMethodListener connectionStart = new ConnectionStartMethodHandler();
IStateAwareMethodListener connectionClose = new ConnectionCloseMethodHandler();
IStateAwareMethodListener connectionCloseOk = new ConnectionCloseOkHandler();
IStateAwareMethodListener connectionTune = new ConnectionTuneMethodHandler();
IStateAwareMethodListener connectionSecure = new ConnectionSecureMethodHandler();
IStateAwareMethodListener connectionOpenOk = new ConnectionOpenOkMethodHandler();
IStateAwareMethodListener channelClose = new ChannelCloseMethodHandler();
IStateAwareMethodListener basicDeliver = new BasicDeliverMethodHandler();
IStateAwareMethodListener basicReturn = new BasicReturnMethodHandler();
IStateAwareMethodListener queueDeleteOk = new QueueDeleteOkMethodHandler();
IStateAwareMethodListener queuePurgeOk = new QueuePurgeOkMethodHandler();
// We need to register a map for the null (i.e. all state) handlers otherwise you get
// a stack overflow in the handler searching code when you present it with a frame for which
// no handlers are registered.
_state2HandlersMap[AMQState.ALL] = new Hashtable();
{
Hashtable notStarted = new Hashtable();
notStarted[typeof(ConnectionStartBody)] = connectionStart;
notStarted[typeof(ConnectionCloseBody)] = connectionClose;
_state2HandlersMap[AMQState.CONNECTION_NOT_STARTED] = notStarted;
}
{
Hashtable notTuned = new Hashtable();
notTuned[typeof(ConnectionTuneBody)] = connectionTune;
notTuned[typeof(ConnectionSecureBody)] = connectionSecure;
notTuned[typeof(ConnectionCloseBody)] = connectionClose;
_state2HandlersMap[AMQState.CONNECTION_NOT_TUNED] = notTuned;
}
{
Hashtable notOpened = new Hashtable();
notOpened[typeof(ConnectionOpenOkBody)] = connectionOpenOk;
notOpened[typeof(ConnectionCloseBody)] = connectionClose;
_state2HandlersMap[AMQState.CONNECTION_NOT_OPENED] = notOpened;
}
{
Hashtable open = new Hashtable();
open[typeof(ChannelCloseBody)] = channelClose;
open[typeof(ConnectionCloseBody)] = connectionClose;
open[typeof(BasicDeliverBody)] = basicDeliver;
open[typeof(BasicReturnBody)] = basicReturn;
open[typeof(QueueDeleteOkBody)] = queueDeleteOk;
open[typeof(QueuePurgeOkBody)] = queuePurgeOk;
_state2HandlersMap[AMQState.CONNECTION_OPEN] = open;
}
{
Hashtable closing = new Hashtable();
closing[typeof(ConnectionCloseOkBody)] = connectionCloseOk;
_state2HandlersMap[AMQState.CONNECTION_CLOSING] = closing;
}
}
public AMQState CurrentState
{
get
{
return _currentState;
}
}
/// <summary>
/// Changes the state.
/// </summary>
/// <param name="newState">The new state.</param>
/// <exception cref="AMQException">if there is an error changing state</exception>
public void ChangeState(AMQState newState)
{
if (InfoLoggingHack)
{
_logger.Debug("State changing to " + newState + " from old state " + _currentState);
}
_logger.Debug("State changing to " + newState + " from old state " + _currentState);
AMQState oldState = _currentState;
_currentState = newState;
lock ( _syncLock )
{
foreach ( IStateListener l in _stateListeners )
{
l.StateChanged(oldState, newState);
}
}
}
public void Error(Exception e)
{
_logger.Debug("State manager receive error notification: " + e);
lock ( _syncLock )
{
foreach ( IStateListener l in _stateListeners )
{
l.Error(e);
}
}
}
public bool MethodReceived(AMQMethodEvent evt)
{
_logger.Debug(String.Format("Finding method handler. currentState={0} type={1}", _currentState, evt.Method.GetType()));
IStateAwareMethodListener handler = FindStateTransitionHandler(_currentState, evt.Method);
if (handler != null)
{
handler.MethodReceived(this, evt);
return true;
}
return false;
}
/// <summary>
/// Finds the state transition handler.
/// </summary>
/// <param name="currentState">State of the current.</param>
/// <param name="frame">The frame.</param>
/// <returns></returns>
/// <exception cref="IllegalStateTransitionException">if the state transition if not allowed</exception>
private IStateAwareMethodListener FindStateTransitionHandler(AMQState currentState,
AMQMethodBody frame)
{
Type clazz = frame.GetType();
if (_logger.IsDebugEnabled)
{
_logger.Debug("Looking for state transition handler for frame " + clazz);
}
IDictionary classToHandlerMap = (IDictionary) _state2HandlersMap[currentState];
if (classToHandlerMap == null)
{
// if no specialised per state handler is registered look for a
// handler registered for "all" states
return FindStateTransitionHandler(AMQState.ALL, frame);
}
IStateAwareMethodListener handler = (IStateAwareMethodListener) classToHandlerMap[clazz];
if (handler == null)
{
if (currentState == AMQState.ALL)
{
_logger.Debug("No state transition handler defined for receiving frame " + frame);
return null;
}
else
{
// if no specialised per state handler is registered look for a
// handler registered for "all" states
return FindStateTransitionHandler(AMQState.ALL, frame);
}
}
else
{
return handler;
}
}
public void AddStateListener(IStateListener listener)
{
_logger.Debug("Adding state listener");
lock ( _syncLock )
{
_stateListeners.Add(listener);
}
}
public void RemoveStateListener(IStateListener listener)
{
lock ( _syncLock )
{
_stateListeners.Remove(listener);
}
}
public void AttainState(AMQState s)
{
if (_currentState != s)
{
StateWaiter sw = null;
try
{
_logger.Debug("Adding state wait to reach state " + s);
sw = new StateWaiter(s);
AddStateListener(sw);
sw.WaituntilStateHasChanged();
// at this point the state will have changed.
}
finally
{
RemoveStateListener(sw);
}
}
}
}
}
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