/*
* This file is provided 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 com.basho.riak.client.cap;
import java.util.concurrent.Callable;
import com.basho.riak.client.RiakRetryFailedException;
import com.basho.riak.client.convert.ConversionException;
import com.basho.riak.client.raw.MatchFoundException;
/**
* A basic retrier implementation that attempts *n* times before throwing a
* {@link UnresolvedConflictException}.
*
* <p>
* Construct it with the number of times a {@link Callable} should be attempted.
* When <code>attempt</code> is called with a {@link Callable} then
* {@link Callable#call()} is run <code>attempts</code> times before throwing a
* {@link RiakRetryFailedException}. It is important to note that there is no
* backoff between attempts.
* </p>
*
* @author russell
*/
public class DefaultRetrier implements Retrier {
private final int attempts;
/**
* @param attempts
* how many times the retrier should attempt the call before
* throwing a {@link RiakRetryFailedException}
*/
public DefaultRetrier(int attempts) {
this.attempts = attempts;
}
/* (non-Javadoc)
* @see com.basho.riak.client.cap.Retrier#attempt(java.util.concurrent.Callable)
*/
public <T> T attempt(Callable<T> command) throws RiakRetryFailedException {
return attempt(command, attempts);
}
/**
* Calls {@link Callable#call()} <code>times</code> before giving up and
* throwing a {@link RiakRetryFailedException} There is no back off.
*
* @param <T>
* the {@link Callable}'s return type.
* @param command
* the {@link Callable} to attempt
* @param times
* how many times to try before we throw
* @return the result of command
* @throws RiakRetryFailedException
* if the Callable throws an exception <code>times</code> times
*/
public static <T> T attempt(final Callable<T> command, final int times) throws RiakRetryFailedException {
try {
return command.call();
} catch (MatchFoundException e) {
throw e;
} catch (ConversionException e) {
throw e;
} catch (Exception e) {
if (times == 0) {
throw new RiakRetryFailedException(e);
} else {
return attempt(command, times - 1);
}
}
}
/**
* Static factory method to create a default retrier
*
* @param attempts
* how many times the {@link DefaultRetrier} will attempt to call
* a {@link Callable} supplied to
* {@link Retrier#attempt(Callable)}
* @return a {@link DefaultRetrier} configured for <code>attempts</code>
* retries
*/
public static Retrier attempts(int attempts) {
return new DefaultRetrier(attempts);
}
}