/*
 * ============LICENSE_START=======================================================
 * ONAP Policy Engine - Common Modules
 * ================================================================================
 * Copyright (C) 2018 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.policy.common.utils.io;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

/**
 * Utilities for testing serialization and de-serialization of objects.
 */
public class Serializer {

    /**
     * The constructor.
     */
    private Serializer() {

    }

    /**
     * Serializes an object into a byte array.
     * 
     * @param object the object to be serialized
     * @return the byte array containing the serialized object
     * @throws IOException if an error occurs
     */
    public static <T> byte[] serialize(T object) throws IOException {
        try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
            try (ObjectOutputStream oos = new ObjectOutputStream(out)) {
                oos.writeObject(object);
            }

            return out.toByteArray();
        }
    }

    /**
     * De-serializes an object from a byte array.
     * 
     * @param clazz class of object that is expected to be de-serialized
     * @param data the byte array containing the serialized object
     * @return the object that was de-serialized from the byte array
     * @throws IOException if an error occurs
     */
    public static <T> T deserialize(Class<T> clazz, byte[] data) throws IOException {

        try (ByteArrayInputStream in = new ByteArrayInputStream(data);
                        ObjectInputStream ois = new ObjectInputStream(in)) {
            return clazz.cast(ois.readObject());

        } catch (ClassNotFoundException e) {
            throw new IOException(e);
        }
    }

    /**
     * Runs an object through a complete round trip, serializing and then de-serializing
     * it.
     * 
     * @param object object to be serialized
     * @return the object that was de-serialized
     * @throws IOException if an error occurs
     */
    @SuppressWarnings("unchecked")
    public static <T> T roundTrip(T object) throws IOException {
        return (T) deserialize(object.getClass(), serialize(object));
    }
}