content: /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *    http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */
  package org.apache.cassandra.utils;
  
  import java.nio.ByteBuffer;
  
  import org.apache.cassandra.db.BufferDecoratedKey;
  import org.apache.cassandra.db.CachedHashDecoratedKey;
  import org.apache.cassandra.dht.Murmur3Partitioner.LongToken;
  import org.apache.cassandra.utils.IFilter.FilterKey;
  
  public class FilterTestHelper
  {
      // used by filter subclass tests
  
      static final double MAX_FAILURE_RATE = 0.1;
      public static final BloomCalculations.BloomSpecification spec = BloomCalculations.computeBloomSpec(15, MAX_FAILURE_RATE);
      static final int ELEMENTS = 10000;
  
      static final FilterKey bytes(String s)
      {
          return new BufferDecoratedKey(new LongToken(0L), ByteBufferUtil.bytes(s));
      }
      
      static final FilterKey wrap(ByteBuffer buf)
      {
          return new BufferDecoratedKey(new LongToken(0L), buf);
      }
  
      static final FilterKey wrapCached(ByteBuffer buf)
      {
          return new CachedHashDecoratedKey(new LongToken(0L), buf);
      }
  
      static final ResetableIterator<ByteBuffer> intKeys()
      {
          return new KeyGenerator.IntGenerator(ELEMENTS);
      }
  
      static final ResetableIterator<ByteBuffer> randomKeys()
      {
          return new KeyGenerator.RandomStringGenerator(314159, ELEMENTS);
      }
  
      static final ResetableIterator<ByteBuffer> randomKeys2()
      {
          return new KeyGenerator.RandomStringGenerator(271828, ELEMENTS);
      }
  
      public static double testFalsePositives(IFilter f, ResetableIterator<ByteBuffer> keys, ResetableIterator<ByteBuffer> otherkeys)
      {
          assert keys.size() == otherkeys.size();
  
          while (keys.hasNext())
          {
              f.add(wrap(keys.next()));
          }
  
          int fp = 0;
          while (otherkeys.hasNext())
          {
              if (f.isPresent(wrap(otherkeys.next())))
              {
                  fp++;
              }
          }
  
          double fp_ratio = fp / (keys.size() * BloomCalculations.probs[spec.bucketsPerElement][spec.K]);
          assert fp_ratio < 1.03 : fp_ratio;
          return fp_ratio;
      }
  
      public void testTrue()
      {
        assert true;
      }
  
  }
  