hbase-server/src/main/java/org/apache/hadoop/hbase/util/RowPrefixFixedLengthBloomContext.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.CellBuilderType;
  24 import org.apache.hadoop.hbase.CellComparator;
  25 import org.apache.hadoop.hbase.CellUtil;
  26 import org.apache.hadoop.hbase.ExtendedCellBuilderFactory;
  27 import org.apache.yetus.audience.InterfaceAudience;
  28
  29 /**
  30  * Handles ROWPREFIX bloom related context.
  31  * It works with both ByteBufferedCell and byte[] backed cells
  32  */
  33 @InterfaceAudience.Private
  34 public class RowPrefixFixedLengthBloomContext extends RowBloomContext {
  35   private final int prefixLength;
  36
  37   public RowPrefixFixedLengthBloomContext(BloomFilterWriter bloomFilterWriter,
  38       CellComparator comparator, int prefixLength) {
  39     super(bloomFilterWriter, comparator);
  40     this.prefixLength = prefixLength;
  41   }
  42
  43   public void writeBloom(Cell cell) throws IOException {
  44     super.writeBloom(getRowPrefixCell(cell));
  45   }
  46
  47   /**
  48    * @param cell the cell
  49    * @return the new cell created by row prefix
  50    */
  51   private Cell getRowPrefixCell(Cell cell) {
  52     byte[] row = CellUtil.copyRow(cell);
  53     return ExtendedCellBuilderFactory.create(CellBuilderType.DEEP_COPY)
  54         .setRow(row, 0, Math.min(prefixLength, row.length))
  55         .setType(Cell.Type.Put)
  56         .build();
  57   }
  58 }