PropertyUtils.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.astro.internal.util;

import java.lang.reflect.Method;

import org.apache.commons.lang.StringUtils;

/**
 * Methods to get the value from a property of an object.
 *
 * @author Gerhard Riegler
 * @since 1.6.0
 */
public class PropertyUtils {

    /**
     * Returns the property value from the object instance, nested properties
     * are possible. If the propertyName is for example rise.start, the methods
     * getRise().getStart() are called.
     */
    public static Object getPropertyValue(Object instance, String property) throws Exception {
        String[] properties = StringUtils.split(property, ".");
        return getPropertyValue(instance, properties, 0);
    }

    /**
     * Returns true, if the specified instance has the specified property.
     */
    public static boolean hasProperty(Object instance, String property) {
        try {
            getPropertyValue(instance, property);
            return true;
        } catch (Exception ex) {
            return false;
        }
    }

    /**
     * Iterates through the nested properties and returns the getter value.
     */
    @SuppressWarnings("all")
    private static Object getPropertyValue(Object instance, String[] properties, int nestedIndex) throws Exception {
        String propertyName = properties[nestedIndex];
        Method m = instance.getClass().getMethod(toGetterString(propertyName), null);
        Object result = m.invoke(instance, (Object[]) null);
        if (++nestedIndex < properties.length) {
            return getPropertyValue(result, properties, nestedIndex);
        }
        return result;
    }

    /**
     * Converts the string to a getter property.
     */
    private static String toGetterString(String str) {
        StringBuilder sb = new StringBuilder();
        sb.append("get");
        sb.append(Character.toTitleCase(str.charAt(0)));
        sb.append(str.substring(1));
        return sb.toString();
    }

}