com.conversantmedia.mapreduce.output.AbstractBloomFilter.java Source code

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Here is the source code for com.conversantmedia.mapreduce.output.AbstractBloomFilter.java

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package com.conversantmedia.mapreduce.output;

/*
 * #%L
 * Mara Core framework
 * ~~
 * Copyright (C) 2015 Conversant
 * ~~
 * 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.
 * #L%
 */

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

import com.google.common.hash.BloomFilter;
import com.google.common.hash.Funnel;

/**
 * Common methods for handling BloomFilters.
 */
public abstract class AbstractBloomFilter {

    @SuppressWarnings("rawtypes")
    protected BloomFilter filter;

    /**
     * This is 1%, not 0.01%.
     */
    protected static final double DEFAULT_FALSE_POSSITIVE = 0.01d;

    /**
     * In order to support serialization the funnel must be serializable.
     * @param expectedInsertions   number of insertions expected
     * @param falsePossitiveRate   the desired false positive probability (must be positive and
     *        less than 1.0)
     * @param funnel            the funnel of T's that the constructed {@code BloomFilter<T>} will use
     * @see com.google.common.hash.BloomFilter#create(Funnel, int, double)
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public void init(final int expectedInsertions, final double falsePossitiveRate, final Funnel funnel) {
        assert funnel instanceof java.io.Serializable;
        filter = BloomFilter.create(funnel, expectedInsertions, falsePossitiveRate);
    }

    /**
     * Serializes the wrapped BloomFilter
     * @param output      destination for serialization
     * @throws IOException   thrown if IO fails
     */
    public void serializeFilter(final ObjectOutputStream output) throws IOException {
        output.writeObject(filter);
    }

    /**
     * Deserializes the BloomFilter into the current wrapper
     * @param input                  destination for deserialization
     * @throws IOException            thrown if reading fails
     * @throws ClassNotFoundException   thrown if unable to locate appropriate class
     */
    @SuppressWarnings("rawtypes")
    public void deserializeFilter(final ObjectInputStream input) throws IOException, ClassNotFoundException {
        filter = (BloomFilter) input.readObject();
    }

}