AddThisBloomFilter.java

/*
 * Copyright 2016 Ben Manes. All Rights Reserved.
 *
 * Licensed 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 com.github.benmanes.caffeine.cache.simulator.membership.bloom;

import com.clearspring.analytics.stream.membership.BloomFilter;
import com.github.benmanes.caffeine.cache.simulator.membership.Membership;
import com.google.common.primitives.Longs;

/**
 * @author ben.manes@gmail.com (Ben Manes)
 */
public final class AddThisBloomFilter implements Membership {
  private final BloomFilter bloomFilter;

  public AddThisBloomFilter(long expectedInsertions, double fpp) {
    bloomFilter = new BloomFilter((int) Math.min(expectedInsertions, Integer.MAX_VALUE), fpp);
  }

  @Override
  public boolean mightContain(long e) {
    return bloomFilter.isPresent(Longs.toByteArray(e));
  }

  @Override
  public void clear() {
    bloomFilter.clear();
  }

  @Override
  public boolean put(long e) {
    byte[] bytes = Longs.toByteArray(e);
    if (bloomFilter.isPresent(bytes)) {
      return false;
    }
    bloomFilter.add(bytes);
    return true;
  }
}