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+#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*/