001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.lang3;
018
019import java.io.ByteArrayInputStream;
020import java.io.ByteArrayOutputStream;
021import java.io.IOException;
022import java.io.InputStream;
023import java.io.ObjectInputStream;
024import java.io.ObjectOutputStream;
025import java.io.ObjectStreamClass;
026import java.io.OutputStream;
027import java.io.Serializable;
028import java.util.HashMap;
029import java.util.Map;
030
031/**
032 * <p>Assists with the serialization process and performs additional functionality based
033 * on serialization.</p>
034 * <p>
035 * <ul>
036 * <li>Deep clone using serialization
037 * <li>Serialize managing finally and IOException
038 * <li>Deserialize managing finally and IOException
039 * </ul>
040 *
041 * <p>This class throws exceptions for invalid {@code null} inputs.
042 * Each method documents its behaviour in more detail.</p>
043 *
044 * <p>#ThreadSafe#</p>
045 * @since 1.0
046 * @version $Id: SerializationUtils.java 1478234 2013-05-01 23:43:35Z sebb $
047 */
048public class SerializationUtils {
049
050    /**
051     * <p>SerializationUtils instances should NOT be constructed in standard programming.
052     * Instead, the class should be used as {@code SerializationUtils.clone(object)}.</p>
053     *
054     * <p>This constructor is public to permit tools that require a JavaBean instance
055     * to operate.</p>
056     * @since 2.0
057     */
058    public SerializationUtils() {
059        super();
060    }
061
062    // Clone
063    //-----------------------------------------------------------------------
064    /**
065     * <p>Deep clone an {@code Object} using serialization.</p>
066     *
067     * <p>This is many times slower than writing clone methods by hand
068     * on all objects in your object graph. However, for complex object
069     * graphs, or for those that don't support deep cloning this can
070     * be a simple alternative implementation. Of course all the objects
071     * must be {@code Serializable}.</p>
072     *
073     * @param <T> the type of the object involved
074     * @param object  the {@code Serializable} object to clone
075     * @return the cloned object
076     * @throws SerializationException (runtime) if the serialization fails
077     */
078    public static <T extends Serializable> T clone(final T object) {
079        if (object == null) {
080            return null;
081        }
082        final byte[] objectData = serialize(object);
083        final ByteArrayInputStream bais = new ByteArrayInputStream(objectData);
084
085        ClassLoaderAwareObjectInputStream in = null;
086        try {
087            // stream closed in the finally
088            in = new ClassLoaderAwareObjectInputStream(bais, object.getClass().getClassLoader());
089            /*
090             * when we serialize and deserialize an object,
091             * it is reasonable to assume the deserialized object
092             * is of the same type as the original serialized object
093             */
094            @SuppressWarnings("unchecked") // see above
095            final
096            T readObject = (T) in.readObject();
097            return readObject;
098
099        } catch (final ClassNotFoundException ex) {
100            throw new SerializationException("ClassNotFoundException while reading cloned object data", ex);
101        } catch (final IOException ex) {
102            throw new SerializationException("IOException while reading cloned object data", ex);
103        } finally {
104            try {
105                if (in != null) {
106                    in.close();
107                }
108            } catch (final IOException ex) {
109                throw new SerializationException("IOException on closing cloned object data InputStream.", ex);
110            }
111        }
112    }
113
114    // Serialize
115    //-----------------------------------------------------------------------
116    /**
117     * <p>Serializes an {@code Object} to the specified stream.</p>
118     *
119     * <p>The stream will be closed once the object is written.
120     * This avoids the need for a finally clause, and maybe also exception
121     * handling, in the application code.</p>
122     *
123     * <p>The stream passed in is not buffered internally within this method.
124     * This is the responsibility of your application if desired.</p>
125     *
126     * @param obj  the object to serialize to bytes, may be null
127     * @param outputStream  the stream to write to, must not be null
128     * @throws IllegalArgumentException if {@code outputStream} is {@code null}
129     * @throws SerializationException (runtime) if the serialization fails
130     */
131    public static void serialize(final Serializable obj, final OutputStream outputStream) {
132        if (outputStream == null) {
133            throw new IllegalArgumentException("The OutputStream must not be null");
134        }
135        ObjectOutputStream out = null;
136        try {
137            // stream closed in the finally
138            out = new ObjectOutputStream(outputStream);
139            out.writeObject(obj);
140
141        } catch (final IOException ex) {
142            throw new SerializationException(ex);
143        } finally {
144            try {
145                if (out != null) {
146                    out.close();
147                }
148            } catch (final IOException ex) { // NOPMD
149                // ignore close exception
150            }
151        }
152    }
153
154    /**
155     * <p>Serializes an {@code Object} to a byte array for
156     * storage/serialization.</p>
157     *
158     * @param obj  the object to serialize to bytes
159     * @return a byte[] with the converted Serializable
160     * @throws SerializationException (runtime) if the serialization fails
161     */
162    public static byte[] serialize(final Serializable obj) {
163        final ByteArrayOutputStream baos = new ByteArrayOutputStream(512);
164        serialize(obj, baos);
165        return baos.toByteArray();
166    }
167
168    // Deserialize
169    //-----------------------------------------------------------------------
170    /**
171     * <p>
172     * Deserializes an {@code Object} from the specified stream.
173     * </p>
174     * 
175     * <p>
176     * The stream will be closed once the object is written. This avoids the need for a finally clause, and maybe also
177     * exception handling, in the application code.
178     * </p>
179     * 
180     * <p>
181     * The stream passed in is not buffered internally within this method. This is the responsibility of your
182     * application if desired.
183     * </p>
184     * 
185     * <p>
186     * If the call site incorrectly types the return value, a {@link ClassCastException} is thrown from the call site.
187     * Without Generics in this declaration, the call site must type cast and can cause the same ClassCastException.
188     * Note that in both cases, the ClassCastException is in the call site, not in this method.
189     * </p>
190     *
191     * @param <T>  the object type to be deserialized
192     * @param inputStream
193     *            the serialized object input stream, must not be null
194     * @return the deserialized object
195     * @throws IllegalArgumentException
196     *             if {@code inputStream} is {@code null}
197     * @throws SerializationException
198     *             (runtime) if the serialization fails
199     */
200    public static <T> T deserialize(final InputStream inputStream) {
201        if (inputStream == null) {
202            throw new IllegalArgumentException("The InputStream must not be null");
203        }
204        ObjectInputStream in = null;
205        try {
206            // stream closed in the finally
207            in = new ObjectInputStream(inputStream);
208            @SuppressWarnings("unchecked") // may fail with CCE if serialised form is incorrect
209            final T obj = (T) in.readObject();
210            return obj;
211
212        } catch (final ClassCastException ex) {
213            throw new SerializationException(ex);
214        } catch (final ClassNotFoundException ex) {
215            throw new SerializationException(ex);
216        } catch (final IOException ex) {
217            throw new SerializationException(ex);
218        } finally {
219            try {
220                if (in != null) {
221                    in.close();
222                }
223            } catch (final IOException ex) { // NOPMD
224                // ignore close exception
225            }
226        }
227    }
228
229    /**
230     * <p>
231     * Deserializes a single {@code Object} from an array of bytes.
232     * </p>
233     * 
234     * <p>
235     * If the call site incorrectly types the return value, a {@link ClassCastException} is thrown from the call site.
236     * Without Generics in this declaration, the call site must type cast and can cause the same ClassCastException.
237     * Note that in both cases, the ClassCastException is in the call site, not in this method.
238     * </p>
239     * 
240     * @param <T>  the object type to be deserialized
241     * @param objectData
242     *            the serialized object, must not be null
243     * @return the deserialized object
244     * @throws IllegalArgumentException
245     *             if {@code objectData} is {@code null}
246     * @throws SerializationException
247     *             (runtime) if the serialization fails
248     */
249    public static <T> T deserialize(final byte[] objectData) {
250        if (objectData == null) {
251            throw new IllegalArgumentException("The byte[] must not be null");
252        }
253        return SerializationUtils.<T>deserialize(new ByteArrayInputStream(objectData));
254    }
255
256    /**
257     * <p>Custom specialization of the standard JDK {@link java.io.ObjectInputStream}
258     * that uses a custom  <code>ClassLoader</code> to resolve a class.
259     * If the specified <code>ClassLoader</code> is not able to resolve the class,
260     * the context classloader of the current thread will be used.
261     * This way, the standard deserialization work also in web-application
262     * containers and application servers, no matter in which of the
263     * <code>ClassLoader</code> the particular class that encapsulates
264     * serialization/deserialization lives. </p>
265     * 
266     * <p>For more in-depth information about the problem for which this
267     * class here is a workaround, see the JIRA issue LANG-626. </p>
268     */
269     static class ClassLoaderAwareObjectInputStream extends ObjectInputStream {
270        private static final Map<String, Class<?>> primitiveTypes = 
271                new HashMap<String, Class<?>>();
272        private final ClassLoader classLoader;
273        
274        /**
275         * Constructor.
276         * @param in The <code>InputStream</code>.
277         * @param classLoader classloader to use
278         * @throws IOException if an I/O error occurs while reading stream header.
279         * @see java.io.ObjectInputStream
280         */
281        public ClassLoaderAwareObjectInputStream(final InputStream in, final ClassLoader classLoader) throws IOException {
282            super(in);
283            this.classLoader = classLoader;
284
285            primitiveTypes.put("byte", byte.class);
286            primitiveTypes.put("short", short.class);
287            primitiveTypes.put("int", int.class);
288            primitiveTypes.put("long", long.class);
289            primitiveTypes.put("float", float.class);
290            primitiveTypes.put("double", double.class);
291            primitiveTypes.put("boolean", boolean.class);
292            primitiveTypes.put("char", char.class);
293            primitiveTypes.put("void", void.class);
294        }
295
296        /**
297         * Overriden version that uses the parametrized <code>ClassLoader</code> or the <code>ClassLoader</code>
298         * of the current <code>Thread</code> to resolve the class.
299         * @param desc An instance of class <code>ObjectStreamClass</code>.
300         * @return A <code>Class</code> object corresponding to <code>desc</code>.
301         * @throws IOException Any of the usual Input/Output exceptions.
302         * @throws ClassNotFoundException If class of a serialized object cannot be found.
303         */
304        @Override
305        protected Class<?> resolveClass(final ObjectStreamClass desc) throws IOException, ClassNotFoundException {
306            final String name = desc.getName();
307            try {
308                return Class.forName(name, false, classLoader);
309            } catch (final ClassNotFoundException ex) {
310                try {
311                    return Class.forName(name, false, Thread.currentThread().getContextClassLoader());
312                } catch (final ClassNotFoundException cnfe) {
313                    final Class<?> cls = primitiveTypes.get(name);
314                    if (cls != null) {
315                        return cls;
316                    } else {
317                        throw cnfe;
318                    }
319                }
320            }
321        }
322
323    }
324
325}