Utils.java

package me.ele.amigo.reflect;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;

public class Utils {

    static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];

    static final Class<?>[] EMPTY_CLASS_ARRAY = new Class[0];

    static boolean isSameLength(final Object[] array1, final Object[] array2) {
        if ((array1 == null && array2 != null && array2.length > 0) ||
                (array2 == null && array1 != null && array1.length > 0) ||
                (array1 != null && array2 != null && array1.length != array2.length)) {
            return false;
        }
        return true;
    }

    static Class<?>[] toClass(final Object... array) {
        if (array == null) {
            return null;
        } else if (array.length == 0) {
            return EMPTY_CLASS_ARRAY;
        }
        final Class<?>[] classes = new Class[array.length];
        for (int i = 0; i < array.length; i++) {
            classes[i] = array[i] == null ? null : array[i].getClass();
        }
        return classes;
    }

    static Class<?>[] nullToEmpty(final Class<?>[] array) {
        if (array == null || array.length == 0) {
            return EMPTY_CLASS_ARRAY;
        }
        return array;
    }

    static Object[] nullToEmpty(final Object[] array) {
        if (array == null || array.length == 0) {
            return EMPTY_OBJECT_ARRAY;
        }
        return array;
    }

    public static List<Class<?>> getAllInterfaces(final Class<?> cls) {
        if (cls == null) {
            return null;
        }
        final LinkedHashSet<Class<?>> interfacesFound = new LinkedHashSet<Class<?>>();
        getAllInterfaces(cls, interfacesFound);
        return new ArrayList<Class<?>>(interfacesFound);
    }

    private static void getAllInterfaces(Class<?> cls, final HashSet<Class<?>> interfacesFound) {
        while (cls != null) {
            final Class<?>[] interfaces = cls.getInterfaces();

            for (final Class<?> i : interfaces) {
                if (interfacesFound.add(i)) {
                    getAllInterfaces(i, interfacesFound);
                }
            }

            cls = cls.getSuperclass();
        }
    }
}