blob: afa5301f39ec2397dcfeff2434780905d668a486 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
/*
*
* 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 log4net;
namespace Apache.Qpid.Client.Failover
{
public abstract class FailoverSupport
{
private static readonly ILog _log = LogManager.GetLogger(typeof(FailoverSupport));
public object execute(AMQConnection con)
{
// We wait until we are not in the middle of failover before acquiring the mutex and then proceeding.
// Any method that can potentially block for any reason should use this class so that deadlock will not
// occur. The FailoverException is propagated by the AMQProtocolHandler to any listeners (e.g. frame listeners)
// that might be causing a block. When that happens, the exception is caught here and the mutex is released
// before waiting for the failover to complete (either successfully or unsuccessfully).
while (true)
{
con.ProtocolListener.BlockUntilNotFailingOver();
lock (con.FailoverMutex)
{
try
{
return operation();
}
catch (FailoverException e)
{
_log.Info("Failover exception caught during operation", e);
}
}
}
}
protected abstract object operation();
}
}
|
