PropertyResolver.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.utils;

import org.apache.commons.lang.StringUtils;

/**
 * This class assists in resolving nested property names.
 *
 * @author Gerhard Riegler
 * @since 1.6.0
 */
public class PropertyResolver {
    private static final String SEPERATOR = ".";

    /**
     * Indicates whether or not the expression contains nested property
     * expressions.
     */
    public static boolean hasNested(String expression) {
        return StringUtils.contains(expression, SEPERATOR);
    }

    /**
     * Extract the next property expression from the current expression.
     */
    public static String first(String expression) {
        return StringUtils.substringBefore(expression, SEPERATOR);
    }

    /**
     * Extract the last property expression from the current expression.
     */
    public static String last(String expression) {
        return StringUtils.substringAfterLast(expression, SEPERATOR);
    }

    /**
     * Remove the first property expresson from the current expression.
     */
    public static String removeFirst(String expression) {
        return StringUtils.substringAfter(expression, SEPERATOR);
    }

    /**
     * Remove the last property expresson from the current expression.
     */
    public static String removeLast(String expression) {
        return StringUtils.substringBeforeLast(expression, SEPERATOR);
    }

    /**
     * Adds a property expression.
     */
    public static String add(String expression, String add) {
        String str1 = StringUtils.trimToNull(expression);
        String str2 = StringUtils.trimToNull(add);

        if (str1 == null && str2 == null) {
            return null;
        } else if (str1 == null && str2 != null) {
            return str2;
        } else if (str1 != null && str2 == null) {
            return str1;
        }
        return str1 + SEPERATOR + str2;
    }

}