Enums.java

/*
 *      Copyright (C) 2015, 2016  higherfrequencytrading.com
 *      Copyright (C) 2016 Roman Leventov
 *
 *      This program is free software: you can redistribute it and/or modify
 *      it under the terms of the GNU Lesser General Public License as published by
 *      the Free Software Foundation, either version 3 of the License.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU Lesser General Public License for more details.
 *
 *      You should have received a copy of the GNU Lesser General Public License
 *      along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.openhft.chronicle.values;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.EnumSet;

public final class Enums {

    private static final Method getUniverse;

    static {
        try {
            getUniverse = EnumSet.class.getDeclaredMethod("getUniverse", Class.class);
            getUniverse.setAccessible(true);
        } catch (NoSuchMethodException e) {
            throw new RuntimeException(e);
        }
    }

    public static <E extends Enum<E>> E[] getUniverse(Class<E> enumType) {
        try {
            //noinspection unchecked
            return (E[]) getUniverse.invoke(null, enumType);
        } catch (IllegalAccessException | InvocationTargetException e) {
            throw new RuntimeException(e);
        }
    }

    public static <E extends Enum<E>> int numberOfConstants(Class<E> enumType) {
        return getUniverse(enumType).length;
    }

    private Enums() {}
}