/**
    *
    * 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.wal;
  
  import java.io.IOException;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.io.util.LRUDictionary;
  import org.apache.hadoop.hbase.util.FSUtils;
  
  import org.apache.hadoop.hbase.wal.DefaultWALProvider;
  
  /**
   * Context used by our wal dictionary compressor. Null if we're not to do our
   * custom dictionary compression.
   */
  @InterfaceAudience.Private
  public abstract class WriterBase implements DefaultWALProvider.Writer {
  
    protected CompressionContext compressionContext;
    protected Configuration conf;
  
    @Override
    public void init(FileSystem fs, Path path, Configuration conf, boolean overwritable) throws IOException {
      this.conf = conf;
    }
  
    public boolean initializeCompressionContext(Configuration conf, Path path) throws IOException {
      boolean doCompress = conf.getBoolean(HConstants.ENABLE_WAL_COMPRESSION, false);
      if (doCompress) {
        try {
          this.compressionContext = new CompressionContext(LRUDictionary.class,
              FSUtils.isRecoveredEdits(path), conf.getBoolean(
                  CompressionContext.ENABLE_WAL_TAGS_COMPRESSION, true));
        } catch (Exception e) {
          throw new IOException("Failed to initiate CompressionContext", e);
        }
      }
      return doCompress;
    }
  
  }