/**
* 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.nutch.crawl;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.nutch.util.ObjectCache;
/** Creates and caches a {@link FetchSchedule} implementation. */
public class FetchScheduleFactory {
public static final Log LOG = LogFactory.getLog(FetchScheduleFactory.class);
private FetchScheduleFactory() {} // no public ctor
/** Return the FetchSchedule implementation. */
public static FetchSchedule getFetchSchedule(Configuration conf) {
String clazz = conf.get("db.fetch.schedule.class", DefaultFetchSchedule.class.getName());
ObjectCache objectCache = ObjectCache.get(conf);
FetchSchedule impl = (FetchSchedule)objectCache.getObject(clazz);
if (impl == null) {
try {
LOG.info("Using FetchSchedule impl: " + clazz);
Class implClass = Class.forName(clazz);
impl = (FetchSchedule)implClass.newInstance();
impl.setConf(conf);
objectCache.setObject(clazz, impl);
} catch (Exception e) {
throw new RuntimeException("Couldn't create " + clazz, e);
}
}
return impl;
}
}
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