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/*
* 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;
import org.apache.qpid.client.AMQConnection;
/**
* FailoverNoopSupport is a {@link FailoverSupport} implementation that does not really provide any failover support
* at all. It wraps a {@link FailoverProtectedOperation} but should that operation throw {@link FailoverException} this
* support class simply re-raises that exception as an IllegalStateException. This support wrapper should only be
* used where the caller can be certain that the failover protected operation cannot acutally throw a failover exception,
* for example, because the caller already holds a lock preventing that condition from arising.
*
* <p><table id="crc"><caption>CRC Card</caption>
* <tr><th> Responsibilities <th> Collaborations
* <tr><td> Perform a fail-over protected operation raising providing no handling of fail-over conditions.
* </table>
*/
public class FailoverNoopSupport<T, E extends Exception> implements FailoverSupport<T, E>
{
/** The protected operation that is to be retried in the event of fail-over. */
FailoverProtectedOperation<T, E> operation;
/** The connection on which the fail-over protected operation is to be performed. */
AMQConnection connection;
/**
* Creates an automatic retrying fail-over handler for the specified operation.
*
* @param operation The fail-over protected operation to wrap in this handler.
*/
public FailoverNoopSupport(FailoverProtectedOperation<T, E> operation, AMQConnection con)
{
this.operation = operation;
this.connection = con;
}
/**
* Delegates to another continuation which is to be provided with fail-over handling.
*
* @return The return value from the delegated to continuation.
* @throws E Any exception that the delegated to continuation may raise.
*/
public T execute() throws E
{
try
{
return operation.execute();
}
catch (FailoverException e)
{
throw new IllegalStateException("Fail-over interupted no-op failover support. "
+ "No-op support should only be used where the caller is certain fail-over cannot occur.", e);
}
}
}
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