| /* |
| * |
| * 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(); |
| } |
| } |