/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */
package org.apache.http.client.utils;

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

import org.apache.http.annotation.Immutable;

/**
 * A collection of utilities to workaround limitations of Java clone framework.
 *
 * @since 4.0
 */
@Immutable
public class CloneUtils {

    /**
     * @since 4.3
     */
    public static <T> T cloneObject(final T obj) throws CloneNotSupportedException {
        if (obj == null) {
            return null;
        }
        if (obj instanceof Cloneable) {
            final Class<?> clazz = obj.getClass ();
            final Method m;
            try {
                m = clazz.getMethod("clone", (Class[]) null);
            } catch (final NoSuchMethodException ex) {
                throw new NoSuchMethodError(ex.getMessage());
            }
            try {
                @SuppressWarnings("unchecked") // OK because clone() preserves the class
                final T result = (T) m.invoke(obj, (Object []) null);
                return result;
            } catch (final InvocationTargetException ex) {
                final Throwable cause = ex.getCause();
                if (cause instanceof CloneNotSupportedException) {
                    throw ((CloneNotSupportedException) cause);
                } else {
                    throw new Error("Unexpected exception", cause);
                }
            } catch (final IllegalAccessException ex) {
                throw new IllegalAccessError(ex.getMessage());
            }
        } else {
            throw new CloneNotSupportedException();
        }
    }

    public static Object clone(final Object obj) throws CloneNotSupportedException {
        return cloneObject(obj);
    }

    /**
     * This class should not be instantiated.
     */
    private CloneUtils() {
    }

}
