/*
 * 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.
 */
package org.apache.commons.lang3;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamClass;
import java.io.OutputStream;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

Assists with the serialization process and performs additional functionality based
on serialization.

Deep clone using serialization
Serialize managing finally and IOException
Deserialize managing finally and IOException

This class throws exceptions for invalid null inputs. Each method documents its behaviour in more detail.
#ThreadSafe#
Since:
1.0/**
 * <p>Assists with the serialization process and performs additional functionality based
 * on serialization.</p>
 *
 * <ul>
 * <li>Deep clone using serialization
 * <li>Serialize managing finally and IOException
 * <li>Deserialize managing finally and IOException
 * </ul>
 *
 * <p>This class throws exceptions for invalid {@code null} inputs.
 * Each method documents its behaviour in more detail.</p>
 *
 * <p>#ThreadSafe#</p>
 * @since 1.0
 */
public class SerializationUtils {

    
SerializationUtils instances should NOT be constructed in standard programming. Instead, the class should be used as SerializationUtils.clone(object).
This constructor is public to permit tools that require a JavaBean instance
to operate.
Since:
2.0/**
     * <p>SerializationUtils instances should NOT be constructed in standard programming.
     * Instead, the class should be used as {@code SerializationUtils.clone(object)}.</p>
     *
     * <p>This constructor is public to permit tools that require a JavaBean instance
     * to operate.</p>
     * @since 2.0
     */
    public SerializationUtils() {
        super();
    }

    // Clone
    //-----------------------------------------------------------------------
    
Deep clone an Object using serialization.
This is many times slower than writing clone methods by hand on all objects in your object graph. However, for complex object graphs, or for those that don't support deep cloning this can be a simple alternative implementation. Of course all the objects must be Serializable.
Params:
object –  the Serializable object to clone
Type parameters:
<T> – the type of the object involved
Throws:
SerializationException – (runtime) if the serialization fails
Returns:
the cloned object/**
     * <p>Deep clone an {@code Object} using serialization.</p>
     *
     * <p>This is many times slower than writing clone methods by hand
     * on all objects in your object graph. However, for complex object
     * graphs, or for those that don't support deep cloning this can
     * be a simple alternative implementation. Of course all the objects
     * must be {@code Serializable}.</p>
     *
     * @param <T> the type of the object involved
     * @param object  the {@code Serializable} object to clone
     * @return the cloned object
     * @throws SerializationException (runtime) if the serialization fails
     */
    public static <T extends Serializable> T clone(final T object) {
        if (object == null) {
            return null;
        }
        final byte[] objectData = serialize(object);
        final ByteArrayInputStream bais = new ByteArrayInputStream(objectData);

        try (ClassLoaderAwareObjectInputStream in = new ClassLoaderAwareObjectInputStream(bais,
                object.getClass().getClassLoader())) {
            /*
             * when we serialize and deserialize an object,
             * it is reasonable to assume the deserialized object
             * is of the same type as the original serialized object
             */
            @SuppressWarnings("unchecked") // see above
            final T readObject = (T) in.readObject();
            return readObject;

        } catch (final ClassNotFoundException ex) {
            throw new SerializationException("ClassNotFoundException while reading cloned object data", ex);
        } catch (final IOException ex) {
            throw new SerializationException("IOException while reading or closing cloned object data", ex);
        }
    }

    
Performs a serialization roundtrip. Serializes and deserializes the given object, great for testing objects that implement Serializable. 
Params:
msg – 
           the object to roundtrip
Type parameters:
<T> – 
          the type of the object involved
Returns:
the serialized and deserialized object
Since:
3.3/**
     * Performs a serialization roundtrip. Serializes and deserializes the given object, great for testing objects that
     * implement {@link Serializable}.
     *
     * @param <T>
     *           the type of the object involved
     * @param msg
     *            the object to roundtrip
     * @return the serialized and deserialized object
     * @since 3.3
     */
    @SuppressWarnings("unchecked") // OK, because we serialized a type `T`
    public static <T extends Serializable> T roundtrip(final T msg) {
        return (T) SerializationUtils.deserialize(SerializationUtils.serialize(msg));
    }

    // Serialize
    //-----------------------------------------------------------------------
    
Serializes an Object to the specified stream.
The stream will be closed once the object is written.
This avoids the need for a finally clause, and maybe also exception
handling, in the application code.
The stream passed in is not buffered internally within this method.
This is the responsibility of your application if desired.
Params:
obj –  the object to serialize to bytes, may be null
outputStream –  the stream to write to, must not be null
Throws:
IllegalArgumentException – if outputStream is null
SerializationException – (runtime) if the serialization fails/**
     * <p>Serializes an {@code Object} to the specified stream.</p>
     *
     * <p>The stream will be closed once the object is written.
     * This avoids the need for a finally clause, and maybe also exception
     * handling, in the application code.</p>
     *
     * <p>The stream passed in is not buffered internally within this method.
     * This is the responsibility of your application if desired.</p>
     *
     * @param obj  the object to serialize to bytes, may be null
     * @param outputStream  the stream to write to, must not be null
     * @throws IllegalArgumentException if {@code outputStream} is {@code null}
     * @throws SerializationException (runtime) if the serialization fails
     */
    public static void serialize(final Serializable obj, final OutputStream outputStream) {
        Validate.isTrue(outputStream != null, "The OutputStream must not be null");
        try (ObjectOutputStream out = new ObjectOutputStream(outputStream)){
            out.writeObject(obj);
        } catch (final IOException ex) {
            throw new SerializationException(ex);
        }
    }

    
Serializes an Object to a byte array for storage/serialization.
Params:
obj –  the object to serialize to bytes
Throws:
SerializationException – (runtime) if the serialization fails
Returns:
a byte[] with the converted Serializable/**
     * <p>Serializes an {@code Object} to a byte array for
     * storage/serialization.</p>
     *
     * @param obj  the object to serialize to bytes
     * @return a byte[] with the converted Serializable
     * @throws SerializationException (runtime) if the serialization fails
     */
    public static byte[] serialize(final Serializable obj) {
        final ByteArrayOutputStream baos = new ByteArrayOutputStream(512);
        serialize(obj, baos);
        return baos.toByteArray();
    }

    // Deserialize
    //-----------------------------------------------------------------------
    
 Deserializes an Object from the specified stream. 

The stream will be closed once the object is written. This avoids the need for a finally clause, and maybe also
exception handling, in the application code.


The stream passed in is not buffered internally within this method. This is the responsibility of your
application if desired.

 If the call site incorrectly types the return value, a ClassCastException is thrown from the call site. Without Generics in this declaration, the call site must type cast and can cause the same ClassCastException. Note that in both cases, the ClassCastException is in the call site, not in this method. 
Params:
inputStream – 
           the serialized object input stream, must not be null
Type parameters:
<T> –  the object type to be deserialized
Throws:
IllegalArgumentException –  if inputStream is null
SerializationException – 
            (runtime) if the serialization fails
Returns:
the deserialized object/**
     * <p>
     * Deserializes an {@code Object} from the specified stream.
     * </p>
     *
     * <p>
     * The stream will be closed once the object is written. This avoids the need for a finally clause, and maybe also
     * exception handling, in the application code.
     * </p>
     *
     * <p>
     * The stream passed in is not buffered internally within this method. This is the responsibility of your
     * application if desired.
     * </p>
     *
     * <p>
     * If the call site incorrectly types the return value, a {@link ClassCastException} is thrown from the call site.
     * Without Generics in this declaration, the call site must type cast and can cause the same ClassCastException.
     * Note that in both cases, the ClassCastException is in the call site, not in this method.
     * </p>
     *
     * @param <T>  the object type to be deserialized
     * @param inputStream
     *            the serialized object input stream, must not be null
     * @return the deserialized object
     * @throws IllegalArgumentException
     *             if {@code inputStream} is {@code null}
     * @throws SerializationException
     *             (runtime) if the serialization fails
     */
    public static <T> T deserialize(final InputStream inputStream) {
        Validate.isTrue(inputStream != null, "The InputStream must not be null");
        try (ObjectInputStream in = new ObjectInputStream(inputStream)) {
            @SuppressWarnings("unchecked")
            final T obj = (T) in.readObject();
            return obj;
        } catch (final ClassNotFoundException | IOException ex) {
            throw new SerializationException(ex);
        }
    }

    
 Deserializes a single Object from an array of bytes. 
 If the call site incorrectly types the return value, a ClassCastException is thrown from the call site. Without Generics in this declaration, the call site must type cast and can cause the same ClassCastException. Note that in both cases, the ClassCastException is in the call site, not in this method. 
Params:
objectData – 
           the serialized object, must not be null
Type parameters:
<T> –  the object type to be deserialized
Throws:
IllegalArgumentException –  if objectData is null
SerializationException – 
            (runtime) if the serialization fails
Returns:
the deserialized object/**
     * <p>
     * Deserializes a single {@code Object} from an array of bytes.
     * </p>
     *
     * <p>
     * If the call site incorrectly types the return value, a {@link ClassCastException} is thrown from the call site.
     * Without Generics in this declaration, the call site must type cast and can cause the same ClassCastException.
     * Note that in both cases, the ClassCastException is in the call site, not in this method.
     * </p>
     *
     * @param <T>  the object type to be deserialized
     * @param objectData
     *            the serialized object, must not be null
     * @return the deserialized object
     * @throws IllegalArgumentException
     *             if {@code objectData} is {@code null}
     * @throws SerializationException
     *             (runtime) if the serialization fails
     */
    public static <T> T deserialize(final byte[] objectData) {
        Validate.isTrue(objectData != null, "The byte[] must not be null");
        return SerializationUtils.deserialize(new ByteArrayInputStream(objectData));
    }

    
Custom specialization of the standard JDK ObjectInputStream that uses a custom ClassLoader to resolve a class.
If the specified ClassLoader is not able to resolve the class,
the context classloader of the current thread will be used.
This way, the standard deserialization work also in web-application
containers and application servers, no matter in which of the
ClassLoader the particular class that encapsulates
serialization/deserialization lives. 
For more in-depth information about the problem for which this
class here is a workaround, see the JIRA issue LANG-626. 
/**
     * <p>Custom specialization of the standard JDK {@link java.io.ObjectInputStream}
     * that uses a custom  <code>ClassLoader</code> to resolve a class.
     * If the specified <code>ClassLoader</code> is not able to resolve the class,
     * the context classloader of the current thread will be used.
     * This way, the standard deserialization work also in web-application
     * containers and application servers, no matter in which of the
     * <code>ClassLoader</code> the particular class that encapsulates
     * serialization/deserialization lives. </p>
     *
     * <p>For more in-depth information about the problem for which this
     * class here is a workaround, see the JIRA issue LANG-626. </p>
     */
     static class ClassLoaderAwareObjectInputStream extends ObjectInputStream {
        private static final Map<String, Class<?>> primitiveTypes =
                new HashMap<>();

        static {
            primitiveTypes.put("byte", byte.class);
            primitiveTypes.put("short", short.class);
            primitiveTypes.put("int", int.class);
            primitiveTypes.put("long", long.class);
            primitiveTypes.put("float", float.class);
            primitiveTypes.put("double", double.class);
            primitiveTypes.put("boolean", boolean.class);
            primitiveTypes.put("char", char.class);
            primitiveTypes.put("void", void.class);
        }

        private final ClassLoader classLoader;

        
Constructor.
Params:
in – The InputStream.
classLoader – classloader to use
Throws:
IOException – if an I/O error occurs while reading stream header.
See Also:
ObjectInputStream/**
         * Constructor.
         * @param in The <code>InputStream</code>.
         * @param classLoader classloader to use
         * @throws IOException if an I/O error occurs while reading stream header.
         * @see java.io.ObjectInputStream
         */
        ClassLoaderAwareObjectInputStream(final InputStream in, final ClassLoader classLoader) throws IOException {
            super(in);
            this.classLoader = classLoader;
        }

        
Overridden version that uses the parameterized ClassLoader or the ClassLoader
of the current Thread to resolve the class.
Params:
desc – An instance of class ObjectStreamClass.
Throws:
IOException – Any of the usual Input/Output exceptions.
ClassNotFoundException – If class of a serialized object cannot be found.
Returns:
A Class object corresponding to desc./**
         * Overridden version that uses the parameterized <code>ClassLoader</code> or the <code>ClassLoader</code>
         * of the current <code>Thread</code> to resolve the class.
         * @param desc An instance of class <code>ObjectStreamClass</code>.
         * @return A <code>Class</code> object corresponding to <code>desc</code>.
         * @throws IOException Any of the usual Input/Output exceptions.
         * @throws ClassNotFoundException If class of a serialized object cannot be found.
         */
        @Override
        protected Class<?> resolveClass(final ObjectStreamClass desc) throws IOException, ClassNotFoundException {
            final String name = desc.getName();
            try {
                return Class.forName(name, false, classLoader);
            } catch (final ClassNotFoundException ex) {
                try {
                    return Class.forName(name, false, Thread.currentThread().getContextClassLoader());
                } catch (final ClassNotFoundException cnfe) {
                    final Class<?> cls = primitiveTypes.get(name);
                    if (cls != null) {
                        return cls;
                    }
                    throw cnfe;
                }
            }
        }

    }

}