BindingConfigParser.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.weather.internal.bus;

import java.math.RoundingMode;

import org.apache.commons.lang.StringUtils;
import org.openhab.binding.weather.internal.common.Unit;
import org.openhab.binding.weather.internal.common.binding.ForecastBindingConfig;
import org.openhab.binding.weather.internal.common.binding.WeatherBindingConfig;
import org.openhab.binding.weather.internal.model.Weather;
import org.openhab.binding.weather.internal.utils.PropertyUtils;
import org.openhab.core.items.Item;
import org.openhab.core.library.types.DecimalType;
import org.openhab.model.item.binding.BindingConfigParseException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Class to parse the key - value base config for an Weather item.
 * <p>
 * Example:
 * </p>
 *
 * <pre>
 * Number  Temperature    "Temperature [%.2f °C]"        {weather="locationId=home, type=temperature, property=current"}
 * Number  Temperature_F  "Temperature [%.2f °F]"        {weather="locationId=home, type=temperature, property=current, unit=fahrenheit"}
 * Number  Humidity       "Humidity [%.0f %]"            {weather="locationId=home, type=atmosphere, property=humidity"}
 * Number  Rain           "Rain [%.2f mm]"               {weather="locationId=home, type=precipitation, property=rain"}
 *
 * Number  Temperature    "Temperature [%.0f °C]"        {weather="locationId=home, type=precipitation, property=rain, roundingMode=ceiling, scale=0"}
 *
 * </pre>
 *
 * @author Gerhard Riegler
 * @since 1.6.0
 */
public class BindingConfigParser {
    private static final Logger logger = LoggerFactory.getLogger(BindingConfigParser.class);

    /**
     * Parses the bindingConfig of an item and returns a WeatherBindingConfig.
     */
    public WeatherBindingConfig parse(Item item, String bindingConfig) throws BindingConfigParseException {
        bindingConfig = StringUtils.trimToEmpty(bindingConfig);
        bindingConfig = StringUtils.removeStart(bindingConfig, "{");
        bindingConfig = StringUtils.removeEnd(bindingConfig, "}");
        String[] entries = bindingConfig.split("[,]");
        WeatherBindingConfigHelper helper = new WeatherBindingConfigHelper();

        for (String entry : entries) {
            String[] entryParts = StringUtils.trimToEmpty(entry).split("[=]");
            if (entryParts.length != 2) {
                throw new BindingConfigParseException("A bindingConfig must have a key and a value");
            }
            String key = StringUtils.trim(entryParts[0]);

            String value = StringUtils.trim(entryParts[1]);
            value = StringUtils.removeStart(value, "\"");
            value = StringUtils.removeEnd(value, "\"");

            try {
                helper.getClass().getDeclaredField(key).set(helper, value);
            } catch (Exception e) {
                throw new BindingConfigParseException("Could not set value " + value + " for attribute " + key);
            }
        }

        if (!helper.isValid()) {
            throw new BindingConfigParseException("Invalid binding: " + bindingConfig);
        }

        helper.type = StringUtils.replace(helper.type, "athmosphere", "atmosphere");

        WeatherBindingConfig weatherConfig = null;
        if (helper.isForecast()) {
            Integer forecast = parseInteger(helper.forecast, bindingConfig);
            if (forecast < 0) {
                throw new BindingConfigParseException("Invalid binding, forecast must be >= 0: " + bindingConfig);
            }
            weatherConfig = new ForecastBindingConfig(helper.locationId, forecast, helper.type, helper.property);
        } else {
            weatherConfig = new WeatherBindingConfig(helper.locationId, helper.type, helper.property);
        }

        Weather validationInstance = new Weather(null);
        String property = weatherConfig.getWeatherProperty();
        if (!Weather.isVirtualProperty(property) && !PropertyUtils.hasProperty(validationInstance, property)) {
            throw new BindingConfigParseException("Invalid binding, unknown type or property: " + bindingConfig);
        }

        boolean isDecimalTypeItem = item.getAcceptedDataTypes().contains(DecimalType.class);
        if (isDecimalTypeItem || Weather.isVirtualProperty(property)) {
            RoundingMode roundingMode = RoundingMode.HALF_UP;
            if (helper.roundingMode != null) {
                try {
                    roundingMode = RoundingMode.valueOf(StringUtils.upperCase(helper.roundingMode));
                } catch (IllegalArgumentException ex) {
                    throw new BindingConfigParseException("Invalid binding, unknown roundingMode: " + bindingConfig);
                }
            }

            Integer scale = 2;
            if (helper.scale != null) {
                scale = parseInteger(helper.scale, bindingConfig);
                if (scale < 0) {
                    throw new BindingConfigParseException("Invalid binding, scale must be >= 0: " + bindingConfig);
                }
            }
            weatherConfig.setScale(roundingMode, scale);
        }

        weatherConfig.setUnit(Unit.parse(helper.unit));
        if (StringUtils.isNotBlank(helper.unit) && weatherConfig.getUnit() == null) {
            throw new BindingConfigParseException("Invalid binding, unknown unit: " + bindingConfig);
        }

        try {
            if (!Weather.isVirtualProperty(property) && weatherConfig.hasUnit()) {
                String doubleTypeName = Double.class.getName();
                String propertyTypeName = PropertyUtils.getPropertyTypeName(validationInstance, property);
                if (!StringUtils.equals(doubleTypeName, propertyTypeName)) {
                    throw new BindingConfigParseException(
                            "Invalid binding, unit specified but property is not a double type: " + bindingConfig);
                }
            }
        } catch (IllegalAccessException ex) {
            logger.error(ex.getMessage(), ex);
            throw new BindingConfigParseException(ex.getMessage());
        }
        return weatherConfig;
    }

    /**
     * Parse a string to a integer value.
     */
    private Integer parseInteger(String valueString, String bindingConfig) throws BindingConfigParseException {
        try {
            return Integer.parseInt(valueString);
        } catch (Exception ex) {
            throw new BindingConfigParseException(
                    "Invalid binding, value " + valueString + " is not a number: " + bindingConfig);
        }
    }

    /**
     * Helper class for parsing the bindingConfig.
     */
    private class WeatherBindingConfigHelper {
        public String locationId;
        public String type;
        public String property;
        public String forecast;
        public String roundingMode;
        public String scale;
        public String unit;

        protected boolean isValid() {
            return StringUtils.isNotBlank(locationId) && StringUtils.isNotBlank(type)
                    && StringUtils.isNotBlank(property);
        }

        protected boolean isForecast() {
            return StringUtils.isNotBlank(forecast);
        }

    }

}