Types.java

/*
 * Copyright 2016 Guillaume Nodet
 *
 * 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.ops4j.pax.cdi.extension.impl.support;

import java.lang.reflect.Array;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;

public class Types {

    @SuppressWarnings("unchecked")
    public static <T> Class<T> getRawType(Type type) {
        if (type instanceof Class<?>) {
            return (Class<T>) type;
        }
        if (type instanceof ParameterizedType) {
            if (((ParameterizedType) type).getRawType() instanceof Class<?>) {
                return (Class<T>) ((ParameterizedType) type).getRawType();
            }
        }
        if (type instanceof TypeVariable<?>) {
            TypeVariable<?> variable = (TypeVariable<?>) type;
            Type[] bounds = variable.getBounds();
            return getBound(bounds);
        }
        if (type instanceof WildcardType) {
            WildcardType wildcard = (WildcardType) type;
            return getBound(wildcard.getUpperBounds());
        }
        if (type instanceof GenericArrayType) {
            GenericArrayType genericArrayType = (GenericArrayType) type;
            Class<?> rawType = getRawType(genericArrayType.getGenericComponentType());
            if (rawType != null) {
                return (Class<T>) Array.newInstance(rawType, 0).getClass();
            }
        }
        return null;
    }

    @SuppressWarnings("unchecked")
    private static <T> Class<T> getBound(Type[] bounds) {
        if (bounds.length == 0) {
            return (Class<T>) Object.class;
        } else {
            return getRawType(bounds[0]);
        }
    }

}