SerializationUtils.java
/*
* 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.Objects;
/**
* Assists with the serialization process and performs additional functionality based
* on serialization.
*
* <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 behavior in more detail.</p>
*
* <p>#ThreadSafe#</p>
* @since 1.0
*/
public class SerializationUtils {
/**
* Custom specialization of the standard JDK {@link ObjectInputStream}
* that uses a custom {@link ClassLoader} to resolve a class.
* If the specified {@link 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
* {@link ClassLoader} the particular class that encapsulates
* serialization/deserialization lives.
*
* <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 final class ClassLoaderAwareObjectInputStream extends ObjectInputStream {
private final ClassLoader classLoader;
/**
* Constructs a new instance.
* @param in The {@link 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 {@link ClassLoader} or the {@link ClassLoader}
* of the current {@link Thread} to resolve the class.
* @param desc An instance of class {@link ObjectStreamClass}.
* @return A {@link Class} object corresponding to {@code 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 = ClassUtils.getPrimitiveClass(name);
if (cls != null) {
return cls;
}
throw cnfe;
}
}
}
}
/**
* Deep clone an {@link Object} using serialization.
*
* <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 {@link Serializable}.</p>
*
* @param <T> the type of the object involved
* @param object the {@link 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);
final Class<T> cls = ObjectUtils.getClass(object);
try (ClassLoaderAwareObjectInputStream in = new ClassLoaderAwareObjectInputStream(bais, cls.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
*/
return cls.cast(in.readObject());
} catch (final ClassNotFoundException | IOException ex) {
throw new SerializationException(
String.format("%s while reading cloned object data", ex.getClass().getSimpleName()), ex);
}
}
/**
* Deserializes a single {@link Object} from an array of bytes.
*
* <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 NullPointerException if {@code objectData} is {@code null}
* @throws SerializationException (runtime) if the serialization fails
*/
public static <T> T deserialize(final byte[] objectData) {
Objects.requireNonNull(objectData, "objectData");
return deserialize(new ByteArrayInputStream(objectData));
}
/**
* Deserializes an {@link Object} from the specified stream.
*
* <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 NullPointerException if {@code inputStream} is {@code null}
* @throws SerializationException (runtime) if the serialization fails
*/
@SuppressWarnings("resource") // inputStream is managed by the caller
public static <T> T deserialize(final InputStream inputStream) {
Objects.requireNonNull(inputStream, "inputStream");
try (ObjectInputStream in = new ObjectInputStream(inputStream)) {
@SuppressWarnings("unchecked")
final T obj = (T) in.readObject();
return obj;
} catch (final ClassNotFoundException | IOException | NegativeArraySizeException ex) {
throw new SerializationException(ex);
}
}
/**
* 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 obj
* 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 obj) {
return (T) deserialize(serialize(obj));
}
/**
* Serializes an {@link 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();
}
/**
* Serializes an {@link Object} to the specified stream.
*
* <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 NullPointerException if {@code outputStream} is {@code null}
* @throws SerializationException (runtime) if the serialization fails
*/
@SuppressWarnings("resource") // outputStream is managed by the caller
public static void serialize(final Serializable obj, final OutputStream outputStream) {
Objects.requireNonNull(outputStream, "outputStream");
try (ObjectOutputStream out = new ObjectOutputStream(outputStream)) {
out.writeObject(obj);
} catch (final IOException ex) {
throw new SerializationException(ex);
}
}
/**
* SerializationUtils instances should NOT be constructed in standard programming.
* Instead, the class should be used as {@code SerializationUtils.clone(object)}.
*
* <p>This constructor is public to permit tools that require a JavaBean instance
* to operate.</p>
* @since 2.0
*
* @deprecated TODO Make private in 4.0.
*/
@Deprecated
public SerializationUtils() {
// empty
}
}