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/*
 * 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 {@code null} inputs. * Each method documents its behaviour in more detail.

* *

#ThreadSafe#

* @since 1.0 */ public class SerializationUtils { /** *

SerializationUtils instances should NOT be constructed in standard programming. * Instead, the class should be used as {@code SerializationUtils.clone(object)}.

* *

This constructor is public to permit tools that require a JavaBean instance * to operate.

* @since 2.0 */ public SerializationUtils() { super(); } // Clone //----------------------------------------------------------------------- /** *

Deep clone an {@code 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 {@code Serializable}.

* * @param 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 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 {@link Serializable}. * * @param * 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 roundtrip(final T msg) { return (T) deserialize(serialize(msg)); } // Serialize //----------------------------------------------------------------------- /** *

Serializes an {@code 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.

* * @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 {@code Object} to a byte array for * storage/serialization.

* * @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 {@code 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 {@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. *

* * @param 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 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 {@code Object} from an array of bytes. *

* *

* 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. *

* * @param 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 deserialize(final byte[] objectData) { Validate.isTrue(objectData != null, "The byte[] must not be null"); return deserialize(new ByteArrayInputStream(objectData)); } /** *

Custom specialization of the standard JDK {@link java.io.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.

*/ static class ClassLoaderAwareObjectInputStream extends ObjectInputStream { private static final Map> 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. * @param in The InputStream. * @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. * @param desc An instance of class ObjectStreamClass. * @return A Class object corresponding to desc. * @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; } } } } }




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