eagle-core/eagle-query/eagle-query-base/src/main/java/org/apache/eagle/query/aggregate/timeseries/GroupbyBucket.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.eagle.query.aggregate.timeseries;

import org.apache.eagle.query.QueryConstants;
import org.apache.eagle.query.aggregate.AggregateFunctionType;
import org.apache.eagle.query.aggregate.raw.GroupbyKey;
import org.apache.eagle.query.aggregate.raw.GroupbyKeyValue;
import org.apache.eagle.query.aggregate.raw.GroupbyValue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class GroupbyBucket {
    private static final Logger LOG = LoggerFactory.getLogger(GroupbyBucket.class);

    public static Map<String, FunctionFactory> functionFactories = new HashMap<>();

    // TODO put this logic to AggregatorFunctionType
    static {
        functionFactories.put(AggregateFunctionType.count.name(), new CountFactory());
        functionFactories.put(AggregateFunctionType.sum.name(), new SumFactory());
        functionFactories.put(AggregateFunctionType.min.name(), new MinFactory());
        functionFactories.put(AggregateFunctionType.max.name(), new MaxFactory());
        functionFactories.put(AggregateFunctionType.avg.name(), new AvgFactory());
    }

    private List<AggregateFunctionType> types;
    // private SortedMap<List<String>, List<Function>> group2FunctionMap =
    //     new TreeMap<List<String>, List<Function>>(new GroupbyFieldsComparator());

    private Map<List<String>, List<Function>> group2FunctionMap = new HashMap<>(); //new GroupbyFieldsComparator());

    public GroupbyBucket(List<AggregateFunctionType> types) {
        this.types = types;
    }

    public void addDatapoint(List<String> groupbyFieldValues, List<Double> values) {
        // LOG.info("DEBUG: addDatapoint: groupby =["+StringUtils.join(groupbyFieldValues,",")+"], values=["+StringUtils.join(values, ",")+"]");

        // locate groupby bucket
        List<Function> functions = group2FunctionMap.get(groupbyFieldValues);
        if (functions == null) {
            functions = new ArrayList<Function>();
            for (AggregateFunctionType type : types) {
                functions.add(functionFactories.get(type.name()).createFunction());
            }
            group2FunctionMap.put(groupbyFieldValues, functions);
        }
        int functionIndex = 0;
        for (Double v : values) {
            functions.get(functionIndex).run(v);
            functionIndex++;
        }
    }

    public Map<List<String>, List<Double>> result() {
        Map<List<String>, List<Double>> result = new HashMap<List<String>, List<Double>>();
        for (Map.Entry<List<String>, List<Function>> entry : this.group2FunctionMap.entrySet()) {
            List<Double> values = new ArrayList<Double>();
            for (Function f : entry.getValue()) {
                values.add(f.result());
            }
            result.put(entry.getKey(), values);
        }
        return result;
    }

    public List<GroupbyKeyValue> getGroupbyKeyValue() {
        List<GroupbyKeyValue>  results = new ArrayList<GroupbyKeyValue>();

        for (Map.Entry<List<String>, List<Function>> entry : this.group2FunctionMap.entrySet()) {
            GroupbyKey key = new GroupbyKey();
            for (String keyStr:entry.getKey()) {
                try {
                    key.addValue(keyStr.getBytes(QueryConstants.CHARSET));
                } catch (UnsupportedEncodingException e) {
                    LOG.error(e.getMessage(),e);
                }
            }
            GroupbyValue value = new GroupbyValue();
            for (Function f : entry.getValue()) {
                value.add(f.result());
                value.addMeta(f.count());
            }
            results.add(new GroupbyKeyValue(key,value));
        }

        return results;
    }

    public static interface FunctionFactory {
        public Function createFunction();
    }

    public abstract static class Function {
        protected int count;

        public abstract void run(double v);

        public abstract double result();

        public int count() {
            return count;
        }

        public void incrCount() {
            count ++;
        }
    }

    private static class CountFactory implements FunctionFactory {

        @Override
        public Function createFunction() {
            return new Count();
        }
    }


    private static class Count extends Sum {

        public Count() {
            super();
        }
    }

    private static class SumFactory implements FunctionFactory {

        @Override
        public Function createFunction() {
            return new Sum();
        }
    }

    private static class Sum extends Function {
        private double summary;

        public Sum() {
            this.summary = 0.0;
        }

        @Override
        public void run(double v) {
            this.incrCount();
            this.summary += v;
        }

        @Override
        public double result() {
            return this.summary;
        }
    }

    private static class MinFactory implements FunctionFactory {

        @Override
        public Function createFunction() {
            return new Min();
        }
    }

    public static class Min extends Function {
        private double minimum;

        public Min() {
            // TODO is this a bug, or only positive numeric calculation is supported
            this.minimum = Double.MAX_VALUE;
        }

        @Override
        public void run(double v) {
            if (v < minimum) {
                minimum = v;
            }
            this.incrCount();
        }

        @Override
        public double result() {
            return minimum;
        }
    }

    private static class MaxFactory implements FunctionFactory {

        @Override
        public Function createFunction() {
            return new Max();
        }
    }

    public static class Max extends Function {
        private double maximum;

        public Max() {
            // TODO is this a bug, or only positive numeric calculation is supported
            this.maximum = 0.0;
        }

        @Override
        public void run(double v) {
            if (v > maximum) {
                maximum = v;
            }
            this.incrCount();
        }

        @Override
        public double result() {
            return maximum;
        }
    }

    private static class AvgFactory implements FunctionFactory {

        @Override
        public Function createFunction() {
            return new Avg();
        }
    }

    public static class Avg extends Function {
        private double total;

        public Avg() {
            this.total = 0.0;
        }

        @Override
        public void run(double v) {
            total += v;
            this.incrCount();
        }

        @Override
        public double result() {
            return this.total / this.count;
        }
    }
}