/*
*
* 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.
*
*/
package org.apache.qpid.proton.messenger.impl;
import java.util.ArrayList;
import java.util.Iterator;
import org.apache.qpid.proton.engine.Delivery;
import org.apache.qpid.proton.messenger.Messenger;
import org.apache.qpid.proton.messenger.Status;
import org.apache.qpid.proton.messenger.Tracker;
import org.apache.qpid.proton.amqp.messaging.Accepted;
import org.apache.qpid.proton.amqp.messaging.Rejected;
import org.apache.qpid.proton.amqp.transport.DeliveryState;
class TrackerQueue
{
private static final Accepted ACCEPTED = Accepted.getInstance();
private static final Rejected REJECTED = new Rejected();
private int _window = 0;
private int _hwm = 0;
private int _lwm = 0;
private ArrayList<Delivery> _deliveries = new ArrayList<Delivery>();
void setWindow(int window)
{
_window = window;
}
int getWindow()
{
return _window;
}
void accept(Tracker tracker)
{
accept(tracker, 0);
}
void accept(Tracker tracker, int flags)
{
apply(tracker, flags, ACCEPT);
}
void reject(Tracker tracker, int flags)
{
apply(tracker, flags, REJECT);
}
void settle(Tracker tracker, int flags)
{
apply(tracker, flags, SETTLE);
}
void add(Delivery delivery)
{
if (delivery == null)
{
throw new NullPointerException("Cannot add null delivery!");
}
int sequence = _hwm++;
_deliveries.add(delivery);
slide();
}
Status getStatus(Tracker tracker)
{
Delivery delivery = getDelivery(tracker);
if (delivery != null)
{
DeliveryState state = delivery.getRemoteState();
if (state != null)
{
return getStatus(state);
}
else if (delivery.remotelySettled() || delivery.isSettled())
{
return getStatus(delivery.getLocalState());
}
else
{
return Status.PENDING;
}
}
else
{
return Status.UNKNOWN;
}
}
private Status getStatus(DeliveryState state)
{
if (state instanceof Accepted)
{
return Status.ACCEPTED;
}
else if (state instanceof Rejected)
{
return Status.REJECTED;
}
else if (state == null)
{
return Status.PENDING;
}
else
{
throw new RuntimeException("Unexpected disposition: " + state);
}
}
void slide()
{
if (_window >= 0)
{
while (_hwm - _lwm > _window)
{
if (_deliveries.isEmpty())
{
throw new RuntimeException("Inconsistent state, empty delivery queue but lwm=" + _lwm + " and hwm=" + _hwm);
}
Delivery d = _deliveries.get(0);
if (d.getLocalState() == null)
{
d.disposition(ACCEPTED);
}
d.settle();
_deliveries.remove(0);
_lwm++;
}
}
}
int getHighWaterMark()
{
return _hwm;
}
Iterator<Delivery> deliveries()
{
return _deliveries.iterator();
}
private Delivery getDelivery(Tracker tracker)
{
int seq = ((TrackerImpl) tracker).getSequence();
if (seq < _lwm || seq > _hwm) return null;
int index = seq - _lwm;
return index < _deliveries.size() ? _deliveries.get(index) : null;
}
static boolean isOutgoing(Tracker tracker)
{
return ((TrackerImpl) tracker).isOutgoing();
}
private void apply(Tracker tracker, int flags, DeliveryOperation operation)
{
int seq = ((TrackerImpl) tracker).getSequence();
if (seq < _lwm || seq > _hwm) return;
int last = seq - _lwm;
int start = (flags & Messenger.CUMULATIVE) != 0 ? 0 : last;
for (int i = start; i <= last && i < _deliveries.size(); ++i)
{
Delivery d = _deliveries.get(i);
if (d != null && !d.isSettled())
{
operation.apply(d);
}
}
}
private static interface DeliveryOperation
{
void apply(Delivery d);
}
private static final DeliveryOperation ACCEPT = new DeliveryOperation()
{
public void apply(Delivery d)
{
if (d.getLocalState() == null) d.disposition(ACCEPTED);
}
};
private static final DeliveryOperation REJECT = new DeliveryOperation()
{
public void apply(Delivery d)
{
if (d.getLocalState() == null) d.disposition(REJECTED);
}
};
private static final DeliveryOperation SETTLE = new DeliveryOperation()
{
public void apply(Delivery d)
{
if (d.getLocalState() == null)
{
d.disposition(d.getRemoteState());
}
d.settle();
}
};
}