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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.hadoop.hbase.regionserver;
import java.io.IOException;
import java.util.List;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.KeyValue.KVComparator;
import org.apache.hadoop.hbase.regionserver.compactions.CompactionContext;
import org.apache.hadoop.hbase.regionserver.compactions.CompactionPolicy;
import org.apache.hadoop.hbase.regionserver.compactions.Compactor;
import org.apache.hadoop.hbase.util.ReflectionUtils;
/**
* StoreEngine is a factory that can create the objects necessary for HStore to operate.
* Since not all compaction policies, compactors and store file managers are compatible,
* they are tied together and replaced together via StoreEngine-s.
*/
@InterfaceAudience.Private
public abstract class StoreEngine {
protected SF storeFlusher;
protected CP compactionPolicy;
protected C compactor;
protected SFM storeFileManager;
/**
* The name of the configuration parameter that specifies the class of
* a store engine that is used to manage and compact HBase store files.
*/
public static final String STORE_ENGINE_CLASS_KEY = "hbase.hstore.engine.class";
private static final Class extends StoreEngine, ?, ?, ?>>
DEFAULT_STORE_ENGINE_CLASS = DefaultStoreEngine.class;
/**
* @return Compaction policy to use.
*/
public CompactionPolicy getCompactionPolicy() {
return this.compactionPolicy;
}
/**
* @return Compactor to use.
*/
public Compactor getCompactor() {
return this.compactor;
}
/**
* @return Store file manager to use.
*/
public StoreFileManager getStoreFileManager() {
return this.storeFileManager;
}
/**
* @return Store flusher to use.
*/
public StoreFlusher getStoreFlusher() {
return this.storeFlusher;
}
/**
* @param filesCompacting Files currently compacting
* @return whether a compaction selection is possible
*/
public abstract boolean needsCompaction(List filesCompacting);
/**
* Creates an instance of a compaction context specific to this engine.
* Doesn't actually select or start a compaction. See CompactionContext class comment.
* @return New CompactionContext object.
*/
public abstract CompactionContext createCompaction() throws IOException;
/**
* Create the StoreEngine's components.
*/
protected abstract void createComponents(
Configuration conf, Store store, KVComparator kvComparator) throws IOException;
private void createComponentsOnce(
Configuration conf, Store store, KVComparator kvComparator) throws IOException {
assert compactor == null && compactionPolicy == null
&& storeFileManager == null && storeFlusher == null;
createComponents(conf, store, kvComparator);
assert compactor != null && compactionPolicy != null
&& storeFileManager != null && storeFlusher != null;
}
/**
* Create the StoreEngine configured for the given Store.
* @param store The store. An unfortunate dependency needed due to it
* being passed to coprocessors via the compactor.
* @param conf Store configuration.
* @param kvComparator KVComparator for storeFileManager.
* @return StoreEngine to use.
*/
public static StoreEngine, ?, ?, ?> create(
Store store, Configuration conf, KVComparator kvComparator) throws IOException {
String className = conf.get(STORE_ENGINE_CLASS_KEY, DEFAULT_STORE_ENGINE_CLASS.getName());
try {
StoreEngine,?,?,?> se = ReflectionUtils.instantiateWithCustomCtor(
className, new Class[] { }, new Object[] { });
se.createComponentsOnce(conf, store, kvComparator);
return se;
} catch (Exception e) {
throw new IOException("Unable to load configured store engine '" + className + "'", e);
}
}
}
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