/*
* 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.brooklyn.core.mgmt.persist;
import static com.google.common.base.Preconditions.checkNotNull;
import org.apache.brooklyn.api.mgmt.rebind.mementos.BrooklynMementoPersister.LookupContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class RetryingMementoSerializer<T> implements MementoSerializer<T> {
private static final Logger LOG = LoggerFactory.getLogger(RetryingMementoSerializer.class);
private final MementoSerializer<T> delegate;
private final int maxAttempts;
public RetryingMementoSerializer(MementoSerializer<T> delegate, int maxAttempts) {
this.delegate = checkNotNull(delegate, "delegate");
this.maxAttempts = maxAttempts;
if (maxAttempts < 1) throw new IllegalArgumentException("Max attempts must be at least 1, but was "+maxAttempts);
}
@Override
public String toString(T memento) {
RuntimeException lastException = null;
int attempt = 0;
do {
attempt++;
try {
String result = delegate.toString(memento);
if (attempt>1)
LOG.info("Success following previous serialization error");
return result;
} catch (RuntimeException e) {
LOG.warn("Error serializing memento (attempt "+attempt+" of "+maxAttempts+") for "+memento+
"; expected sometimes if attribute value modified", e);
lastException = e;
}
} while (attempt < maxAttempts);
throw lastException;
}
@Override
public T fromString(String string) {
if (string==null)
return null;
RuntimeException lastException = null;
int attempt = 0;
do {
attempt++;
try {
T result = delegate.fromString(string);
if (attempt>1)
LOG.info("Success following previous deserialization error, got: "+result);
return result;
} catch (RuntimeException e) {
// trying multiple times only makes sense for a few errors (namely ConcModExceptions); perhaps deprecate that strategy?
LOG.warn("Error deserializing memento (attempt "+attempt+" of "+maxAttempts+"): "+e, e);
if (attempt==1) LOG.debug("Memento which was not deserialized is:\n"+string);
lastException = e;
}
} while (attempt < maxAttempts);
throw lastException;
}
@Override
public void setLookupContext(LookupContext lookupContext) {
delegate.setLookupContext(lookupContext);
}
@Override
public void unsetLookupContext() {
delegate.unsetLookupContext();
}
}