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Diffstat (limited to 'trunk/qpid/java/client/src/main/java/org/apache/qpid/client/failover/FailoverException.java')
-rw-r--r-- | trunk/qpid/java/client/src/main/java/org/apache/qpid/client/failover/FailoverException.java | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/trunk/qpid/java/client/src/main/java/org/apache/qpid/client/failover/FailoverException.java b/trunk/qpid/java/client/src/main/java/org/apache/qpid/client/failover/FailoverException.java new file mode 100644 index 0000000000..037b0dc2d1 --- /dev/null +++ b/trunk/qpid/java/client/src/main/java/org/apache/qpid/client/failover/FailoverException.java @@ -0,0 +1,49 @@ +/* + * + * 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.client.failover; + +/** + * FailoverException is used to indicate that a synchronous request has failed to receive the reply that it is waiting + * for because the fail-over process has been started whilst it was waiting for its reply. Synchronous methods generally + * raise this exception to indicate that they must be re-tried once the fail-over process has completed. + * + * <p/><table id="crc"><caption>CRC Card</caption> + * <tr><th> Responsibilities <th> Collaborations + * <tr><td> Used to indicate failure of a synchronous request due to fail-over. + * </table> + * + * @todo This exception is created and passed as an argument to a method, rather than thrown. The exception is being + * used to represent an event, passed out to other threads. Use of exceptions as arguments rather than as + * exceptions is extremly confusing. Ideally use a condition or set a flag and check it instead. + * This exceptions-as-events pattern seems to be in a similar style to Mina code, which is not pretty, but + * potentially acceptable for that reason. We have the option of extending the mina model to add more events + * to it, that is, anything that is interested in handling failover as an event occurs below the main + * amq event handler, which knows the specific interface of the qpid handlers, which can pass this down as + * an explicit event, without it being an exception. Add failover method to BlockingMethodFrameListener, + * have it set a flag or interrupt the waiting thread, which then creates and raises this exception. + */ +public class FailoverException extends Exception +{ + public FailoverException(String message) + { + super(message); + } +} |