eagle-core/eagle-query/eagle-query-base/src/main/java/org/apache/eagle/query/aggregate/raw/Function.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.raw;

public abstract class Function {
    private int count = 0;

    protected void incrCount(int num) {
        count += num;
    }

    public int count() {
        return count;
    }

    public abstract void run(double v,int count);

    public void run(double v) {
        run(v, 1);
    }

    public abstract double result();

    public static class Avg extends Function {
        private double total;

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

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

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

    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,int count) {
            this.incrCount(count);
            if (v > maximum) {
                maximum = v;
            }
        }

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

    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,int count) {
            this.incrCount(count);
            if (v < minimum) {
                minimum = v;
            }
        }

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

    public static class Sum extends Function {
        private double summary;

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

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

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

    public static class Count extends Sum {

        public Count() {
            super();
        }

    }
}