hbase-server/src/main/java/org/apache/hadoop/hbase/util/BloomContext.java

   1 /**
   2  * Licensed to the Apache Software Foundation (ASF) under one
   3  * or more contributor license agreements.  See the NOTICE file
   4  * distributed with this work for additional information
   5  * regarding copyright ownership.  The ASF licenses this file
   6  * to you under the Apache License, Version 2.0 (the
   7  * "License"); you may not use this file except in compliance
   8  * with the License.  You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  */
  18 package org.apache.hadoop.hbase.util;
  19
  20 import java.io.IOException;
  21
  22 import org.apache.hadoop.hbase.Cell;
  23 import org.apache.hadoop.hbase.CellComparator;
  24 import org.apache.yetus.audience.InterfaceAudience;
  25 import org.apache.hadoop.hbase.io.hfile.HFile;
  26
  27 /**
  28  * The bloom context that is used by the StorefileWriter to add the bloom details
  29  * per cell
  30  */
  31 @InterfaceAudience.Private
  32 public abstract class BloomContext {
  33
  34   protected BloomFilterWriter bloomFilterWriter;
  35   protected CellComparator comparator;
  36
  37   public BloomContext(BloomFilterWriter bloomFilterWriter, CellComparator comparator) {
  38     this.bloomFilterWriter = bloomFilterWriter;
  39     this.comparator = comparator;
  40   }
  41
  42   public Cell getLastCell() {
  43     return this.bloomFilterWriter.getPrevCell();
  44   }
  45
  46   /**
  47    * Bloom information from the cell is retrieved
  48    * @param cell
  49    * @throws IOException
  50    */
  51   public void writeBloom(Cell cell) throws IOException {
  52     // only add to the bloom filter on a new, unique key
  53     if (isNewKey(cell)) {
  54       sanityCheck(cell);
  55       bloomFilterWriter.append(cell);
  56     }
  57   }
  58
  59   private void sanityCheck(Cell cell) throws IOException {
  60     if (this.getLastCell() != null) {
  61       if (comparator.compare(cell, this.getLastCell()) <= 0) {
  62         throw new IOException("Added a key not lexically larger than" + " previous. Current cell = "
  63             + cell + ", prevCell = " + this.getLastCell());
  64       }
  65     }
  66   }
  67
  68   /**
  69    * Adds the last bloom key to the HFile Writer as part of StorefileWriter close.
  70    * @param writer
  71    * @throws IOException
  72    */
  73   public abstract void addLastBloomKey(HFile.Writer writer) throws IOException;
  74
  75   /**
  76    * Returns true if the cell is a new key as per the bloom type
  77    * @param cell the cell to be verified
  78    * @return true if a new key else false
  79    */
  80   protected abstract boolean isNewKey(Cell cell);
  81 }