ceph/src/rocksdb/java/src/main/java/org/rocksdb/util/ReverseBytewiseComparator.java

   1 // Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 // This source code is licensed under the BSD-style license found in the
   3 // LICENSE file in the root directory of this source tree. An additional grant
   4 // of patent rights can be found in the PATENTS file in the same directory.
   5
   6 package org.rocksdb.util;
   7
   8 import org.rocksdb.BuiltinComparator;
   9 import org.rocksdb.ComparatorOptions;
  10 import org.rocksdb.Slice;
  11
  12 /**
  13  * This is a Java Native implementation of the C++
  14  * equivalent ReverseBytewiseComparatorImpl using {@link Slice}
  15  *
  16  * The performance of Comparators implemented in Java is always
  17  * less than their C++ counterparts due to the bridging overhead,
  18  * as such you likely don't want to use this apart from benchmarking
  19  * and you most likely instead wanted
  20  * {@link BuiltinComparator#REVERSE_BYTEWISE_COMPARATOR}
  21  */
  22 public class ReverseBytewiseComparator extends BytewiseComparator {
  23
  24   public ReverseBytewiseComparator(final ComparatorOptions copt) {
  25     super(copt);
  26   }
  27
  28   @Override
  29   public String name() {
  30     return "rocksdb.java.ReverseBytewiseComparator";
  31   }
  32
  33   @Override
  34   public int compare(final Slice a, final Slice b) {
  35     return -super.compare(a, b);
  36   }
  37 }