JMeter example source code file (Calculator.java)

This example JMeter source code file (Calculator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - JMeter tags/keywords

calculator, calculator, long, long, number, number, string, string

The JMeter Calculator.java source code

/*
 * 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.jmeter.util;

import org.apache.jmeter.samplers.SampleResult;

/**
 * Class to calculate various items that don't require all previous results to be saved:
 * - mean = average
 * - standard deviation
 * - minimum
 * - maximum
 */
public class Calculator {

    private double sum = 0;

    private double sumOfSquares = 0;

    private double mean = 0;

    private double deviation = 0;

    private int count = 0;

    private long bytes = 0;

    private long maximum = Long.MIN_VALUE;

    private long minimum = Long.MAX_VALUE;

    private int errors = 0;

    private final String label;

    public Calculator() {
        this("");
    }

    public Calculator(String label) {
        this.label = label;
    }

    public void clear() {
        maximum = Long.MIN_VALUE;
        minimum = Long.MAX_VALUE;
        sum = 0;
        sumOfSquares = 0;
        mean = 0;
        deviation = 0;
        count = 0;
    }

    public void addValue(long newValue) {
        addValue(newValue,1);
    }

    private void addValue(long newValue, int sampleCount) {
        count += sampleCount;
        double currentVal = newValue;
        sum += currentVal;
        if (sampleCount > 1){
            minimum=Math.min(newValue/sampleCount, minimum);
            maximum=Math.max(newValue/sampleCount, maximum);
            // For n values in an aggregate sample the average value = (val/n)
            // So need to add n * (val/n) * (val/n) = val * val / n
            sumOfSquares += (currentVal * currentVal) / (sampleCount);
        } else {
            minimum=Math.min(newValue, minimum);
            maximum=Math.max(newValue, maximum);
            sumOfSquares += currentVal * currentVal;
        }
        // Calculate each time, as likely to be called for each add
        mean = sum / count;
        deviation = Math.sqrt((sumOfSquares / count) - (mean * mean));
    }


    public void addBytes(long newValue) {
        bytes += newValue;
    }

    private long startTime = 0;
    private long elapsedTime = 0;

    public void addSample(SampleResult res) {
        addBytes(res.getBytes());
        addValue(res.getTime(),res.getSampleCount());
        errors+=res.getErrorCount(); // account for multiple samples
        if (startTime == 0){
            startTime=res.getStartTime();
        }
        startTime = Math.min(startTime, res.getStartTime());
        elapsedTime = Math.max(elapsedTime, res.getEndTime()-startTime);
    }


    public long getTotalBytes() {
        return bytes;
    }


    public double getMean() {
        return mean;
    }

    public Number getMeanAsNumber() {
        return new Long((long) mean);
    }

    public double getStandardDeviation() {
        return deviation;
    }

    public long getMin() {
        return minimum;
    }

    public long getMax() {
        return maximum;
    }

    public int getCount() {
        return count;
    }

    public String getLabel() {
        return label;
    }

    /**
     * Returns the raw double value of the percentage of samples with errors
     * that were recorded. (Between 0.0 and 1.0)
     *
     * @return the raw double value of the percentage of samples with errors
     *         that were recorded.
     */
    public double getErrorPercentage() {
        double rval = 0.0;

        if (count == 0) {
            return (rval);
        }
        rval = (double) errors / (double) count;
        return (rval);
    }

    /**
     * Returns the throughput associated to this sampler in requests per second.
     * May be slightly skewed because it takes the timestamps of the first and
     * last samples as the total time passed, and the test may actually have
     * started before that start time and ended after that end time.
     */
    public double getRate() {
        if (elapsedTime == 0) {
            return 0.0;
        }

        return ((double) count / (double) elapsedTime ) * 1000;
    }

    /**
     * calculates the average page size, which means divide the bytes by number
     * of samples.
     *
     * @return average page size in bytes
     */
    public double getAvgPageBytes() {
        if (count > 0 && bytes > 0) {
            return (double) bytes / count;
        }
        return 0.0;
    }

    /**
     * Throughput in bytes / second
     *
     * @return throughput in bytes/second
     */
    public double getBytesPerSecond() {
        if (elapsedTime > 0) {
            return bytes / ((double) elapsedTime / 1000); // 1000 = millisecs/sec
        }
        return 0.0;
    }

    /**
     * Throughput in kilobytes / second
     *
     * @return Throughput in kilobytes / second
     */
    public double getKBPerSecond() {
        return getBytesPerSecond() / 1024; // 1024=bytes per kb
    }

}