org.eclipse.osbp.runtime.common/src/org/eclipse/osbp/runtime/common/annotations/PropertiesUtil.java

/**
 * Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
 * 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
 *
 * Contributors:
 *         Florian Pirchner - Initial implementation
 */
package org.eclipse.osbp.runtime.common.annotations;

import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.lang.reflect.FieldUtils;

/**
 * The Class PropertiesUtil.
 */
public class PropertiesUtil {

	/**
	 * Returns true, if the property in object contains a @Property with the
	 * given key.
	 *
	 * @param object
	 *            the object
	 * @param property
	 *            the property may be nested
	 * @param key
	 *            the key
	 * @return true, if successful
	 */
	public static boolean hasKey(Object object, String property, String key) {
		return hasKey(object.getClass(), property, key);
	}

	/**
	 * Returns true, if the property in clazz contains a @Property with the
	 * given key.
	 *
	 * @param clazz
	 *            the clazz
	 * @param property
	 *            the property may be nested
	 * @param key
	 *            the key
	 * @return true, if successful
	 */
	public static boolean hasKey(Class<?> clazz, String property, String key) {
		return getValue(clazz, property, key) != null;
	}

	/**
	 * Returns the value of @Property, from the property in object containing a @Property
	 * with the given key.
	 *
	 * @param object
	 *            the object
	 * @param property
	 *            the property may be nested
	 * @param key
	 *            the key
	 * @return the value
	 */
	public static String getValue(Object object, String property, String key) {
		return getValue(object.getClass(), property, key);
	}

	/**
	 * Returns the value of @Property, from the property in clazz containing a @Property
	 * with the given key.
	 *
	 * @param clazz
	 *            the clazz
	 * @param property
	 *            the property may be nested
	 * @param key
	 *            the key
	 * @return the value
	 */
	public static String getValue(Class<?> clazz, String property, String key) {
		Field f = getFieldWithNested(clazz, property);
		if (f == null) {
			return null;
		}

		Properties props = f.getAnnotation(Properties.class);
		if (props == null) {
			return null;
		}

		for (Property prop : props.properties()) {
			if (prop.key().equals(key)) {
				return prop.value();
			}
		}

		return null;
	}

	/**
	 * Returns the field, based on the property. Properties may be nested.
	 * 
	 * @param clazz
	 * @param property
	 * @return
	 */
	protected static Field getFieldWithNested(Class<?> clazz, String property) {
		Field result = null;
		if (property.contains(".")) {
			// first top-level property, then go deeper in a loop
			Class<?> propertyClass = clazz;
			String[] tokens = property.split("\\.");
			for (int i = 0; i < tokens.length; i++) {
				String token = tokens[i].trim();
				result = FieldUtils.getField(propertyClass, token, true);
				if (result == null) {
					throw new IllegalStateException(String.format(
							"Can not access %s for %s", property,
							clazz.getName()));
				}
				propertyClass = result.getType();
			}
		} else {
			result = FieldUtils.getField(clazz, property, true);
		}
		return result;
	}

	/**
	 * Returns a map with all key value pairs contained in @Properties.
	 *
	 * @param object
	 *            the object
	 * @param property
	 *            the property may be nested
	 * @param key
	 *            the key
	 * @return the properties
	 */
	public static Map<String, String> getProperties(Object object,
			String property, String key) {
		return getProperties(object.getClass(), property, key);
	}

	/**
	 * Returns a map with all key value pairs contained in @Properties.
	 *
	 * @param clazz
	 *            the clazz
	 * @param property
	 *            the property may be nested
	 * @param key
	 *            the key
	 * @return the properties
	 */
	public static Map<String, String> getProperties(Class<?> clazz,
			String property, String key) {
		Field f = getFieldWithNested(clazz, property);
		if (f == null) {
			return null;
		}

		Properties props = f.getAnnotation(Properties.class);
		if (props == null) {
			return null;
		}

		Map<String, String> result = new HashMap<String, String>();
		for (Property prop : props.properties()) {
			result.put(prop.key(), prop.value());
		}

		return result;
	}

}