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Common functionality for HBase

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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.io.encoding;

import java.io.IOException;

import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.io.hfile.BlockType;
import org.apache.hadoop.hbase.io.hfile.HFileContext;
import org.apache.hadoop.hbase.util.Bytes;

/**
 * An encoding context that is created by a writer's encoder, and is shared
 * across the writer's whole lifetime.
 *
 * @see HFileBlockDecodingContext for decoding
 *
 */
@InterfaceAudience.Private
public interface HFileBlockEncodingContext {

  /**
   * @return the block type after encoding
   */
  BlockType getBlockType();

  /**
   * @return the {@link DataBlockEncoding} encoding used
   */
  DataBlockEncoding getDataBlockEncoding();

  /**
   * Do any action that needs to be performed after the encoding.
   * Compression is also included if a non-null compression algorithm is used
   *
   * @param blockType
   * @throws IOException
   */
  void postEncoding(BlockType blockType) throws IOException;

  /**
   * Releases the resources used.
   */
  void close();

  /**
   * @return HFile context information
   */
  HFileContext getHFileContext();

  /**
   * Sets the encoding state.
   * @param state
   */
  void setEncodingState(EncodingState state);

  /**
   * @return the encoding state
   */
  EncodingState getEncodingState();

  /**
   * @param data encoded bytes with header
   * @param offset the offset in encoded data to start at
   * @param length the number of encoded bytes
   * @return Bytes with header which are ready to write out to disk.
   *         This is compressed and encrypted bytes applying the set compression
   *         algorithm and encryption. The bytes may be changed.
   *         If need a Bytes reference for later use, clone the bytes and use that.
   *         Null if the data doesn't need to be compressed and encrypted.
   */
  Bytes compressAndEncrypt(byte[] data, int offset, int length) throws IOException;
}