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Diffstat (limited to 'qpid/cpp/include/qpid/client/FailoverManager.h')
-rw-r--r-- | qpid/cpp/include/qpid/client/FailoverManager.h | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/qpid/cpp/include/qpid/client/FailoverManager.h b/qpid/cpp/include/qpid/client/FailoverManager.h new file mode 100644 index 0000000000..d3a0dbc976 --- /dev/null +++ b/qpid/cpp/include/qpid/client/FailoverManager.h @@ -0,0 +1,137 @@ +#ifndef QPID_CLIENT_FAILOVERMANAGER_H +#define QPID_CLIENT_FAILOVERMANAGER_H + +/* + * + * 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. + * + */ + +#include "qpid/Exception.h" +#include "qpid/client/AsyncSession.h" +#include "qpid/client/ClientImportExport.h" +#include "qpid/client/Connection.h" +#include "qpid/client/ConnectionSettings.h" +#include "qpid/client/FailoverListener.h" +#include "qpid/sys/Monitor.h" +#include <vector> + +namespace qpid { +namespace client { + +struct CannotConnectException : qpid::Exception +{ + CannotConnectException(const std::string& m) : qpid::Exception(m) {} +}; + +/** + * Utility to manage failover. + */ +class QPID_CLIENT_CLASS_EXTERN FailoverManager +{ + public: + /** + * Interface to implement for doing work that can be resumed on + * failover + */ + struct Command + { + /** + * This method will be called with isRetry=false when the + * command is first executed. The session to use for the work + * will be passed to the implementing class. If the connection + * fails while the execute call is in progress, the + * FailoverManager controlling the execution will re-establish + * a connection, open a new session and call back to the + * Command implementations execute method with the new session + * and isRetry=true. + */ + virtual void execute(AsyncSession& session, bool isRetry) = 0; + virtual ~Command() {} + }; + + struct ReconnectionStrategy + { + /** + * This method is called by the FailoverManager prior to + * establishing a connection (or re-connection) and can be + * used if the application wishes to edit or re-order the list + * which will default to the list of known brokers for the + * last connection. + */ + virtual void editUrlList(std::vector<Url>& urls) = 0; + virtual ~ReconnectionStrategy() {} + }; + + /** + * Create a manager to control failover for a logical connection. + * + * @param settings the initial connection settings + * @param strategy optional stratgey callback allowing application + * to edit or reorder the list of urls to which reconnection is + * attempted + */ + QPID_CLIENT_EXTERN FailoverManager(const ConnectionSettings& settings, ReconnectionStrategy* strategy = 0); + /** + * Return the current connection if open or attept to reconnect to + * the specified list of urls. If no list is specified the list of + * known brokers from the last connection will be used. If no list + * is specified and this is the first connect attempt, the host + * and port from the initial settings will be used. + * + * If the full list is tried and all attempts fail, + * CannotConnectException is thrown. + */ + QPID_CLIENT_EXTERN Connection& connect(std::vector<Url> brokers = std::vector<Url>()); + /** + * Return the current connection whether open or not + */ + QPID_CLIENT_EXTERN Connection& getConnection(); + /** + * Close the current connection + */ + QPID_CLIENT_EXTERN void close(); + /** + * Reliably execute the specified command. This involves creating + * a session on which to carry out the work of the command, + * handling failover occuring while exeuting that command and + * re-starting the work. + * + * Multiple concurrent threads can call execute with different + * commands; each thread will be allocated its own + * session. FailoverManager will coordinate the different threads + * on failover to ensure they continue to use the same logical + * connection. + */ + QPID_CLIENT_EXTERN void execute(Command&); + private: + enum State {IDLE, CONNECTING, CANT_CONNECT}; + + qpid::sys::Monitor lock; + Connection connection; + std::auto_ptr<FailoverListener> failoverListener; + ConnectionSettings settings; + ReconnectionStrategy* strategy; + State state; + + void attempt(Connection&, ConnectionSettings settings, std::vector<Url> urls); + void attempt(Connection&, ConnectionSettings settings); +}; +}} // namespace qpid::client + +#endif /*!QPID_CLIENT_FAILOVERMANAGER_H*/ |