org.kiji.scoring.statistics.RunningLogarithmicBin.java Source code

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Here is the source code for org.kiji.scoring.statistics.RunningLogarithmicBin.java

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/**
 * (c) Copyright 2013 WibiData, Inc.
 *
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * 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 org.kiji.scoring.statistics;

import java.util.Map;
import java.util.NavigableMap;
import java.util.concurrent.atomic.AtomicLong;

import com.google.common.base.Objects;
import com.google.common.collect.Maps;

import org.kiji.annotations.ApiAudience;
import org.kiji.annotations.ApiStability;

/** Bins positive values by order of magnitude. */
@ApiAudience.Public
@ApiStability.Experimental
public final class RunningLogarithmicBin {
    private final NavigableMap<Long, AtomicLong> mBins;

    /**
     * Create the initial empty bins.
     *
     * @param binCount the number of bins in this RunningLogarithmicBin.
     */
    private void populateBins(final int binCount) {
        mBins.put(0L, new AtomicLong(0));
        for (int i = 0; i < binCount; i++) {
            mBins.put((long) Math.pow(10.0, -1 + i), new AtomicLong(0));
        }
    }

    /**
     * Initialize a new RunningLogarithmicBin of a given size.
     *
     * @param binCount the desired number of bins in this RunningLogarithmicBin.
     */
    public RunningLogarithmicBin(final int binCount) {
        mBins = Maps.newTreeMap();
        populateBins(binCount);
    }

    /**
     * Increment the counter for the bin into which the given value falls.
     *
     * @param value the value to bin.
     */
    public void addValue(final long value) {
        mBins.floorEntry(value).getValue().incrementAndGet();
    }

    /**
     * Get the number of values in the bin into which the given value falls.
     *
     * @param value the value from which to derive a bin.
     * @return the number of values in the bin into which the given value falls.
     */
    public long getCount(final long value) {
        return mBins.floorEntry(value).getValue().get();
    }

    /**
     * Get the entire bin structure.  Modifications made to the return value will not be reflected in
     * the underlying Map.
     *
     * @return a copy of the entire bin structure.
     */
    public NavigableMap<Long, Long> getBins() {
        final Map<Long, AtomicLong> binsCopy = Maps.newHashMap(mBins);
        final NavigableMap<Long, Long> output = Maps.newTreeMap();
        for (Map.Entry<Long, AtomicLong> entry : binsCopy.entrySet()) {
            output.put(entry.getKey(), entry.getValue().get());
        }
        return output;
    }

    /** {@inheritDoc} */
    @Override
    public String toString() {
        return Objects.toStringHelper(this).add("bins", getBins()).toString();
    }
}