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.DataOutputStream;
021import java.io.IOException;
022import org.apache.hadoop.conf.Configuration;
023import org.apache.hadoop.hbase.Cell;
024import org.apache.hadoop.hbase.io.encoding.DataBlockEncoding;
025import org.apache.hadoop.hbase.io.encoding.EncodingState;
026import org.apache.hadoop.hbase.io.encoding.HFileBlockDecodingContext;
027import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext;
028import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultEncodingContext;
029import org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext;
030import org.apache.hadoop.hbase.io.encoding.NoneEncoder;
031import org.apache.yetus.audience.InterfaceAudience;
032
033/**
034 * Does not perform any kind of encoding/decoding.
035 */
036@InterfaceAudience.Private
037public class NoOpDataBlockEncoder implements HFileDataBlockEncoder {
038
039  public static final NoOpDataBlockEncoder INSTANCE = new NoOpDataBlockEncoder();
040
041  private static class NoneEncodingState extends EncodingState {
042    NoneEncoder encoder = null;
043  }
044
045  /** Cannot be instantiated. Use {@link #INSTANCE} instead. */
046  private NoOpDataBlockEncoder() {
047  }
048
049  @Override
050  public void encode(Cell cell, HFileBlockEncodingContext encodingCtx, DataOutputStream out)
051    throws IOException {
052    NoneEncodingState state = (NoneEncodingState) encodingCtx.getEncodingState();
053    NoneEncoder encoder = state.encoder;
054    int size = encoder.write(cell);
055    state.postCellEncode(size, size);
056  }
057
058  @Override
059  public boolean useEncodedScanner() {
060    return false;
061  }
062
063  @Override
064  public void saveMetadata(HFile.Writer writer) {
065  }
066
067  @Override
068  public DataBlockEncoding getDataBlockEncoding() {
069    return DataBlockEncoding.NONE;
070  }
071
072  @Override
073  public DataBlockEncoding getEffectiveEncodingInCache(boolean isCompaction) {
074    return DataBlockEncoding.NONE;
075  }
076
077  @Override
078  public String toString() {
079    return getClass().getSimpleName();
080  }
081
082  @Override
083  public HFileBlockEncodingContext newDataBlockEncodingContext(Configuration conf,
084    byte[] dummyHeader, HFileContext meta) {
085    return new HFileBlockDefaultEncodingContext(conf, null, dummyHeader, meta);
086  }
087
088  @Override
089  public HFileBlockDecodingContext newDataBlockDecodingContext(Configuration conf,
090    HFileContext meta) {
091    return new HFileBlockDefaultDecodingContext(conf, meta);
092  }
093
094  @Override
095  public void startBlockEncoding(HFileBlockEncodingContext blkEncodingCtx, DataOutputStream out)
096    throws IOException {
097    if (blkEncodingCtx.getClass() != HFileBlockDefaultEncodingContext.class) {
098      throw new IOException(this.getClass().getName() + " only accepts "
099        + HFileBlockDefaultEncodingContext.class.getName() + " as the " + "encoding context.");
100    }
101
102    HFileBlockDefaultEncodingContext encodingCtx =
103      (HFileBlockDefaultEncodingContext) blkEncodingCtx;
104    encodingCtx.prepareEncoding(out);
105
106    NoneEncoder encoder = new NoneEncoder(out, encodingCtx);
107    NoneEncodingState state = new NoneEncodingState();
108    state.encoder = encoder;
109    blkEncodingCtx.setEncodingState(state);
110  }
111
112  @Override
113  public void endBlockEncoding(HFileBlockEncodingContext encodingCtx, DataOutputStream out,
114    byte[] uncompressedBytesWithHeader, BlockType blockType) throws IOException {
115    encodingCtx.postEncoding(BlockType.DATA);
116  }
117}