/*
 * Copyright (c) OSGi Alliance (2017). All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.osgi.util.converter;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

/**
 * @author $Id$
 */
class DTOUtil {
	private DTOUtil() {
		// Do not instantiate. This is a utility class.
	}

	static boolean isDTOType(Class< ? > cls) {
		try {
			cls.getDeclaredConstructor();
		} catch (NoSuchMethodException | SecurityException e) {
			// No zero-arg constructor, not a DTO
			return false;
		}

		if (cls.getDeclaredMethods().length > 0) {
			// should not have any methods
			return false;
		}

		for (Method m : cls.getMethods()) {
			try {
				Object.class.getMethod(m.getName(), m.getParameterTypes());
			} catch (NoSuchMethodException snme) {
				// Not a method defined by Object.class (or override of such
				// method)
				return false;
			}
		}

		/*
		 * for (Field f : cls.getDeclaredFields()) { int modifiers =
		 * f.getModifiers(); if (Modifier.isStatic(modifiers)) { // ignore
		 * static fields continue; } if (!Modifier.isPublic(modifiers)) { return
		 * false; } }
		 */

		boolean foundField = false;
		for (Field f : cls.getFields()) {
			int modifiers = f.getModifiers();
			if (Modifier.isStatic(modifiers)) {
				// ignore static fields
				continue;
			}

			if (!Modifier.isPublic(modifiers)) {
				return false;
			}
			foundField = true;
		}
		return foundField;
	}
}