io.druid.query.aggregation.HistogramAggregatorFactory.java Source code

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Here is the source code for io.druid.query.aggregation.HistogramAggregatorFactory.java

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/*
 * Druid - a distributed column store.
 * Copyright 2012 - 2015 Metamarkets Group Inc.
 *
 * 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 io.druid.query.aggregation;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
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.common.StringUtils;
import io.druid.segment.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.makeFloatColumnSelector(fieldName), breaks);
    }

    @Override
    public BufferAggregator factorizeBuffered(ColumnSelectorFactory metricFactory) {
        return new HistogramBufferAggregator(metricFactory.makeFloatColumnSelector(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 List<AggregatorFactory> getRequiredColumns() {
        return Arrays.<AggregatorFactory>asList(new HistogramAggregatorFactory(fieldName, fieldName, 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(StringUtils.toUtf8((String) object));
            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 = StringUtils.toUtf8(fieldName);
        ByteBuffer buf = ByteBuffer.allocate(1 + fieldNameBytes.length + Floats.BYTES * breaks.length)
                .put(CACHE_TYPE_ID).put(fieldNameBytes).put((byte) 0xFF);
        buf.asFloatBuffer().put(breaks);

        return buf.array();
    }

    @Override
    public String getTypeName() {
        return "histogram";
    }

    @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) + '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        HistogramAggregatorFactory that = (HistogramAggregatorFactory) o;

        if (!Arrays.equals(breaks, that.breaks)) {
            return false;
        }
        if (breaksList != null ? !breaksList.equals(that.breaksList) : that.breaksList != null) {
            return false;
        }
        if (fieldName != null ? !fieldName.equals(that.fieldName) : that.fieldName != null) {
            return false;
        }
        if (name != null ? !name.equals(that.name) : that.name != null) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        int result = name != null ? name.hashCode() : 0;
        result = 31 * result + (fieldName != null ? fieldName.hashCode() : 0);
        result = 31 * result + (breaksList != null ? breaksList.hashCode() : 0);
        result = 31 * result + (breaks != null ? Arrays.hashCode(breaks) : 0);
        return result;
    }
}