001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.io.hfile;
019
020import java.io.DataOutput;
021import java.io.IOException;
022import org.apache.hadoop.hbase.Cell;
023import org.apache.hadoop.hbase.CellComparator;
024import org.apache.hadoop.hbase.ExtendedCell;
025import org.apache.hadoop.hbase.io.HeapSize;
026import org.apache.hadoop.hbase.io.encoding.DataBlockEncoding;
027import org.apache.hadoop.hbase.io.encoding.IndexBlockEncoding;
028import org.apache.hadoop.hbase.util.Bytes;
029import org.apache.yetus.audience.InterfaceAudience;
030
031/**
032 * Controls what kind of index block encoding is used. If index block encoding is not set or the
033 * given block is not a index block (encoded or not), methods should just return the unmodified
034 * block.
035 */
036@InterfaceAudience.Private
037public interface HFileIndexBlockEncoder {
038  /** Type of encoding used for index blocks in HFile. Stored in file info. */
039  byte[] INDEX_BLOCK_ENCODING = Bytes.toBytes("INDEX_BLOCK_ENCODING");
040
041  /**
042   * Save metadata in HFile which will be written to disk
043   * @param writer writer for a given HFile
044   * @exception IOException on disk problems
045   */
046  void saveMetadata(HFile.Writer writer) throws IOException;
047
048  void encode(BlockIndexChunk blockIndexChunk, boolean rootIndexBlock, DataOutput out)
049    throws IOException;
050
051  /** Returns the index block encoding */
052  IndexBlockEncoding getIndexBlockEncoding();
053
054  EncodedSeeker createSeeker();
055
056  interface EncodedSeeker extends HeapSize {
057    void initRootIndex(HFileBlock blk, int numEntries, CellComparator comparator, int treeLevel)
058      throws IOException;
059
060    boolean isEmpty();
061
062    ExtendedCell getRootBlockKey(int i);
063
064    int getRootBlockCount();
065
066    ExtendedCell midkey(HFile.CachingBlockReader cachingBlockReader) throws IOException;
067
068    int rootBlockContainingKey(Cell key);
069
070    BlockWithScanInfo loadDataBlockWithScanInfo(ExtendedCell key, HFileBlock currentBlock,
071      boolean cacheBlocks, boolean pread, boolean isCompaction,
072      DataBlockEncoding expectedDataBlockEncoding, HFile.CachingBlockReader cachingBlockReader)
073      throws IOException;
074  }
075}