EnumHelper.java

/*
 * Copyright 2013 The Sculptor Project Team, including the original 
 * author or authors.
 * 
 * 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.sculptor.framework.util;

import java.lang.reflect.Method;

public class EnumHelper {

	public static <T extends Enum<T>> Enum<T> toEnum(Class<T> enumClass,
			Object value) {
		assert enumClass != null;
		if (value == null) {
			return null;
		}
		try {
			Method method = enumClass.getMethod("toEnum", Object.class);
			@SuppressWarnings("unchecked")
			Enum<T> cast = (Enum<T>) method.invoke(null, value);
			return cast;
		} catch (Exception e) {
			throw new IllegalArgumentException("value " + value
					+ " can not be converted to Enum '"
					+ enumClass.getSimpleName() + "'", e);
		}
	}

	public static Object toData(Enum<?> enumClass) {
		if (enumClass == null) {
			return null;
		}
		try {
			Method method = enumClass.getClass().getMethod("toData");
			return method.invoke(enumClass);
		} catch (Exception e) {
			throw new IllegalArgumentException("Enum '"
					+ enumClass.getClass().getSimpleName()
					+ "' can not be converted to value", e);
		}
	}

	public static boolean isIdentifierAttributeOfTypeString(Class<? extends Enum<?>> enumClass) {
		if (enumClass == null) {
			return false;
		}
		try {
			Method[] methods = enumClass.getMethods();
			for (Method method : methods) {
				if (method.getName().startsWith("from") && method.getReturnType().equals(enumClass)) {
					Class<?>[] parameterTypes = method.getParameterTypes();
					if (parameterTypes.length == 1 && parameterTypes[0].equals(String.class)) {
						return true;
					}
				}
			}
			return false;
		} catch (Exception e) {
			throw new IllegalArgumentException("Enum '"
					+ enumClass.getClass().getSimpleName()
					+ "' can not examined for identifier attribute type", e);
		}
	}

}