/*
* 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 gobblin.compaction.listeners;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Optional;
import com.google.common.base.Strings;
import org.apache.commons.lang3.reflect.ConstructorUtils;
import gobblin.configuration.State;
/**
* Implementation of {@link CompactorListenerFactory} that creates a {@link CompactorListener} using reflection. The
* config key {@link #COMPACTOR_LISTENERS} is used to specify a comma separated list of compactors to use. These
* compactors will be run serially.
*/
public class ReflectionCompactorListenerFactory implements CompactorListenerFactory {
@VisibleForTesting
static final String COMPACTOR_LISTENERS = "compactor.listeners";
@Override
public Optional<CompactorListener> createCompactorListener(Properties properties)
throws CompactorListenerCreationException {
State state = new State(properties);
if (Strings.isNullOrEmpty(state.getProp(COMPACTOR_LISTENERS))) {
return Optional.absent();
}
List<CompactorListener> listeners = new ArrayList<>();
for (String listenerClassName : state.getPropAsList(COMPACTOR_LISTENERS)) {
try {
listeners.add((CompactorListener) ConstructorUtils
.invokeConstructor(Class.forName(listenerClassName), properties));
} catch (ReflectiveOperationException e) {
throw new CompactorListenerCreationException(String
.format("Unable to create CompactorListeners from key \"%s\" with value \"%s\"", COMPACTOR_LISTENERS,
properties.getProperty(COMPACTOR_LISTENERS)), e);
}
}
return Optional.<CompactorListener>of(new SerialCompactorListener(listeners));
}
}