NetatmoPressureUnit.java

/**
 * Copyright (c) 2010-2016 by the respective copyright holders.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */
package org.openhab.binding.netatmo.internal.weather;

import java.math.BigDecimal;

import org.apache.commons.lang.StringUtils;

/**
 * @author Rob Nielsen
 * @since 1.8.0
 *
 *        This enum holds all the different pressure units for the Netatmo
 *        binding, along with conversion methods
 */
public enum NetatmoPressureUnit {
    MBAR("mbar"),
    INHG("inHg"),
    MMHG("mmHg");

    public static final NetatmoPressureUnit DEFAULT_PRESSURE_UNIT = NetatmoPressureUnit.MBAR;

    private static final BigDecimal MBAR_TO_INHG = new BigDecimal("0.0295");

    private static final BigDecimal MBAR_TO_MMHG = new BigDecimal("0.7500");

    String pressureUnit;

    private NetatmoPressureUnit(String pressureUnit) {
        this.pressureUnit = pressureUnit;
    }

    public String getpressureUnit() {
        return pressureUnit;
    }

    public static NetatmoPressureUnit fromString(String pressureUnit) {
        if (!StringUtils.isEmpty(pressureUnit)) {
            for (NetatmoPressureUnit pressureUnitType : NetatmoPressureUnit.values()) {
                if (pressureUnitType.toString().equalsIgnoreCase(pressureUnit)) {
                    return pressureUnitType;
                }
            }
        }
        throw new IllegalArgumentException("Invalid pressureUnit: " + pressureUnit);
    }

    /**
     * Convert to appropriate measurement.
     *
     * The Barometer is accurate to +-1 mbar or +- 0.03 inHg
     *
     * @param value
     *            pressure in mbars
     *
     * @return value in proper measurement
     */
    public BigDecimal convertPressure(BigDecimal value) {
        if (this == DEFAULT_PRESSURE_UNIT) {
            return value;
        } else if (this == INHG) {
            return value.multiply(MBAR_TO_INHG);
        } else { // MMGH
            return value.multiply(MBAR_TO_MMHG);
        }
    }
}