samples/utils/src/main/java/org/apache/edgent/samples/utils/sensor/SimulatedTemperatureSensor.java

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package org.apache.edgent.samples.utils.sensor;

import java.util.Objects;

import org.apache.edgent.analytics.sensors.Range;
import org.apache.edgent.analytics.sensors.Ranges;
import org.apache.edgent.function.Supplier;

/**
 * A Simulated temperature sensor.
 * <p>
 * The sensor starts off with an initial value.
 * Each call to {@link #get()} changes the current value by
 * a random amount between plus/minus a {@code deltaFactor}.
 * The new current value is limited to a {@code tempRange}
 * and then rounded to 1 fractional digit.
 * </p><p>
 * No temperature scale is implied (e.g., Fahrenheit, Kelvin, ...).
 * The {@code double} temperature values are simply generated as described.
 * The user of the class decides how to interpret them.
 * </p><p>
 * Sample use:
 * <pre>{@code
 * Topology t = ...;
 * SimulatedTemperatureSensor tempSensor = new SimulatedTemperatureSensor();
 * TStream<Double> temp = t.poll(tempSensor, 1, TimeUnit.SECONDS);
 * }</pre>
 * @see SimpleSimulatedSensor
 */
public class SimulatedTemperatureSensor implements Supplier<Double> {
    private static final long serialVersionUID = 1L;
    private final SimpleSimulatedSensor sensor;
   
    /**
     * Create a temperature sensor.
     * <p>
     * Same as {@code SimulatedTemperatureSensor(80.0, 
     *              Ranges.closed(28.0, 112.0), 1.0)}
     * </p><p>
     * These default values roughly correspond to normal air temperature
     * in the Fahrenheit scale.
     * </p>
     */
    public SimulatedTemperatureSensor() {
        this(80.0, Ranges.closed(28.0, 112.0), 1.0);
    }
    
    /**
     * Create a temperature sensor.
     * <p>
     * No temperature scale is implied.
     * </p> 
     * @param initialTemp the initial temperature.  Must be within tempRange.
     * @param tempRange maximum sensor value range
     * @param deltaFactor maximum plus/minus change on each {@code get()}.
     *              e.g., 1.0 to limit change to +/- 1.0.
     *              Must be &gt; 0.0
     */
    public SimulatedTemperatureSensor(double initialTemp,
            Range<Double> tempRange, double deltaFactor) {
        Objects.requireNonNull(tempRange, "tempRange");
        if (!tempRange.contains(initialTemp))
            throw new IllegalArgumentException("initialTemp");
        if (deltaFactor <= 0.0)
            throw new IllegalArgumentException("deltaFactor");
        sensor = new SimpleSimulatedSensor(initialTemp, deltaFactor, tempRange);
    }
    
    /** Get the tempRange setting
     * @return the value
     */
    public Range<Double> getTempRange() {
        return sensor.getRange();
    }
    
    /** Get the deltaFactor setting
     * @return the value
     */
    public double getDeltaFactor() {
        return sensor.getDeltaFactor();
    }
    
    /** Get the next sensor value. */
    @Override
    public Double get() {
        return sensor.get();
    }
}