com.metamx.druid.aggregation.HistogramAggregatorFactory.java Source code

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Here is the source code for com.metamx.druid.aggregation.HistogramAggregatorFactory.java

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/*
 * Druid - a distributed column store.
 * Copyright (C) 2012  Metamarkets Group Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package com.metamx.druid.aggregation;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.common.primitives.Floats;
import com.google.common.primitives.Longs;
import com.metamx.druid.processing.ColumnSelectorFactory;
import org.apache.commons.codec.binary.Base64;

import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

public class HistogramAggregatorFactory implements AggregatorFactory {
    private static final byte CACHE_TYPE_ID = 0x7;

    private final String name;
    private final String fieldName;
    private final List<Float> breaksList;

    private final float[] breaks;

    @JsonCreator
    public HistogramAggregatorFactory(@JsonProperty("name") String name,
            @JsonProperty("fieldName") final String fieldName,
            @JsonProperty("breaks") final List<Float> breaksList) {
        Preconditions.checkNotNull(name, "Must have a valid, non-null aggregator name");
        Preconditions.checkNotNull(fieldName, "Must have a valid, non-null fieldName");

        this.name = name;
        this.fieldName = fieldName;
        this.breaksList = (breaksList == null) ? Lists.<Float>newArrayList() : breaksList;
        this.breaks = new float[this.breaksList.size()];
        for (int i = 0; i < this.breaksList.size(); ++i) {
            this.breaks[i] = this.breaksList.get(i);
        }
    }

    @Override
    public Aggregator factorize(ColumnSelectorFactory metricFactory) {
        return new HistogramAggregator(name, metricFactory.makeFloatMetricSelector(fieldName), breaks);
    }

    @Override
    public BufferAggregator factorizeBuffered(ColumnSelectorFactory metricFactory) {
        return new HistogramBufferAggregator(metricFactory.makeFloatMetricSelector(fieldName), breaks);
    }

    @Override
    public Comparator getComparator() {
        return HistogramAggregator.COMPARATOR;
    }

    @Override
    public Object combine(Object lhs, Object rhs) {
        return HistogramAggregator.combineHistograms(lhs, rhs);
    }

    @Override
    public AggregatorFactory getCombiningFactory() {
        return new HistogramAggregatorFactory(name, name, breaksList);
    }

    @Override
    public Object deserialize(Object object) {
        if (object instanceof byte[]) {
            return Histogram.fromBytes((byte[]) object);
        } else if (object instanceof ByteBuffer) {
            return Histogram.fromBytes((ByteBuffer) object);
        } else if (object instanceof String) {
            byte[] bytes = Base64.decodeBase64(((String) object).getBytes(Charsets.UTF_8));
            return Histogram.fromBytes(bytes);
        }
        return object;
    }

    @Override
    public Object finalizeComputation(Object object) {
        return ((Histogram) object).asVisual();
    }

    @Override
    @JsonProperty
    public String getName() {
        return name;
    }

    @JsonProperty
    public String getFieldName() {
        return fieldName;
    }

    @JsonProperty
    public List<Float> getBreaks() {
        return breaksList;
    }

    @Override
    public List<String> requiredFields() {
        return Arrays.asList(fieldName);
    }

    @Override
    public byte[] getCacheKey() {
        byte[] fieldNameBytes = fieldName.getBytes();
        return ByteBuffer.allocate(1 + fieldNameBytes.length).put(CACHE_TYPE_ID).put(fieldNameBytes).array();
    }

    @Override
    public String getTypeName() {
        throw new UnsupportedOperationException("HistogramAggregatorFactory does not support getTypeName()");
    }

    @Override
    public int getMaxIntermediateSize() {
        return Longs.BYTES * (breaks.length + 1) + Floats.BYTES * 2;
    }

    @Override
    public Object getAggregatorStartValue() {
        return new Histogram(breaks);
    }

    @Override
    public String toString() {
        return "HistogramAggregatorFactory{" + "name='" + name + '\'' + ", fieldName='" + fieldName + '\''
                + ", breaks=" + Arrays.toString(breaks) + '}';
    }
}