/**
    *
    * 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.fs.Path;
  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
  import org.apache.hadoop.hbase.KeyValue.KVComparator;
  import org.apache.hadoop.hbase.regionserver.compactions.CompactionContext;
  import org.apache.hadoop.hbase.regionserver.compactions.ExploringCompactionPolicy;
  import org.apache.hadoop.hbase.regionserver.compactions.RatioBasedCompactionPolicy;
  import org.apache.hadoop.hbase.regionserver.compactions.DefaultCompactor;
  import org.apache.hadoop.hbase.regionserver.compactions.CompactionThroughputController;
  import org.apache.hadoop.hbase.security.User;
  import org.apache.hadoop.hbase.util.ReflectionUtils;
  
  /**
   * Default StoreEngine creates the default compactor, policy, and store file manager, or
   * their derivatives.
   */
  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
  public class DefaultStoreEngine extends StoreEngine<
    DefaultStoreFlusher, RatioBasedCompactionPolicy, DefaultCompactor, DefaultStoreFileManager> {
  
    public static final String DEFAULT_STORE_FLUSHER_CLASS_KEY =
        "hbase.hstore.defaultengine.storeflusher.class";
    public static final String DEFAULT_COMPACTOR_CLASS_KEY =
        "hbase.hstore.defaultengine.compactor.class";
    public static final String DEFAULT_COMPACTION_POLICY_CLASS_KEY =
        "hbase.hstore.defaultengine.compactionpolicy.class";
  
    private static final Class<? extends DefaultStoreFlusher>
      DEFAULT_STORE_FLUSHER_CLASS = DefaultStoreFlusher.class;
    private static final Class<? extends DefaultCompactor>
      DEFAULT_COMPACTOR_CLASS = DefaultCompactor.class;
    private static final Class<? extends RatioBasedCompactionPolicy>
      DEFAULT_COMPACTION_POLICY_CLASS = ExploringCompactionPolicy.class;
  
    @Override
    public boolean needsCompaction(List<StoreFile> filesCompacting) {
      return compactionPolicy.needsCompaction(
          this.storeFileManager.getStorefiles(), filesCompacting);
    }
  
    @Override
    protected void createComponents(
        Configuration conf, Store store, KVComparator kvComparator) throws IOException {
      createCompactor(conf, store);
      createCompactionPolicy(conf, store);
      createStoreFlusher(conf, store);
      storeFileManager = new DefaultStoreFileManager(kvComparator, conf, compactionPolicy.getConf());
    }
  
    protected void createCompactor(Configuration conf, Store store) throws IOException {
      String className = conf.get(DEFAULT_COMPACTOR_CLASS_KEY, DEFAULT_COMPACTOR_CLASS.getName());
      try {
        compactor = ReflectionUtils.instantiateWithCustomCtor(className,
            new Class[] { Configuration.class, Store.class }, new Object[] { conf, store });
      } catch (Exception e) {
        throw new IOException("Unable to load configured compactor '" + className + "'", e);
      }
    }
  
    protected void createCompactionPolicy(Configuration conf, Store store) throws IOException {
      String className = conf.get(
          DEFAULT_COMPACTION_POLICY_CLASS_KEY, DEFAULT_COMPACTION_POLICY_CLASS.getName());
      try {
        compactionPolicy = ReflectionUtils.instantiateWithCustomCtor(className,
            new Class[] { Configuration.class, StoreConfigInformation.class },
            new Object[] { conf, store });
      } catch (Exception e) {
        throw new IOException("Unable to load configured compaction policy '" + className + "'", e);
      }
    }
  
    protected void createStoreFlusher(Configuration conf, Store store) throws IOException {
      String className = conf.get(
          DEFAULT_STORE_FLUSHER_CLASS_KEY, DEFAULT_STORE_FLUSHER_CLASS.getName());
      try {
       storeFlusher = ReflectionUtils.instantiateWithCustomCtor(className,
           new Class[] { Configuration.class, Store.class }, new Object[] { conf, store });
     } catch (Exception e) {
       throw new IOException("Unable to load configured store flusher '" + className + "'", e);
     }
   }
 
 
   @Override
   public CompactionContext createCompaction() {
     return new DefaultCompactionContext();
   }
 
   private class DefaultCompactionContext extends CompactionContext {
     @Override
     public boolean select(List<StoreFile> filesCompacting, boolean isUserCompaction,
         boolean mayUseOffPeak, boolean forceMajor) throws IOException {
       request = compactionPolicy.selectCompaction(storeFileManager.getStorefiles(),
           filesCompacting, isUserCompaction, mayUseOffPeak, forceMajor);
       return request != null;
     }
 
     @Override
     public List<Path> compact(CompactionThroughputController throughputController)
         throws IOException {
       return compact(throughputController, null);
     }
 
     @Override
     public List<Path> compact(CompactionThroughputController throughputController, User user)
         throws IOException {
       return compactor.compact(request, throughputController, user);
     }
 
     @Override
     public List<StoreFile> preSelect(List<StoreFile> filesCompacting) {
       return compactionPolicy.preSelectCompactionForCoprocessor(
           storeFileManager.getStorefiles(), filesCompacting);
     }
   }
 
 }