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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.lang3;
18  
19  import java.io.ByteArrayInputStream;
20  import java.io.ByteArrayOutputStream;
21  import java.io.IOException;
22  import java.io.InputStream;
23  import java.io.ObjectInputStream;
24  import java.io.ObjectOutputStream;
25  import java.io.ObjectStreamClass;
26  import java.io.OutputStream;
27  import java.io.Serializable;
28  import java.util.HashMap;
29  import java.util.Map;
30  
31  /**
32   * <p>Assists with the serialization process and performs additional functionality based
33   * on serialization.</p>
34   *
35   * <ul>
36   * <li>Deep clone using serialization
37   * <li>Serialize managing finally and IOException
38   * <li>Deserialize managing finally and IOException
39   * </ul>
40   *
41   * <p>This class throws exceptions for invalid {@code null} inputs.
42   * Each method documents its behaviour in more detail.</p>
43   *
44   * <p>#ThreadSafe#</p>
45   * @since 1.0
46   * @version $Id: SerializationUtils.java 1583482 2014-03-31 22:54:57Z niallp $
47   */
48  public class SerializationUtils {
49  
50      /**
51       * <p>SerializationUtils instances should NOT be constructed in standard programming.
52       * Instead, the class should be used as {@code SerializationUtils.clone(object)}.</p>
53       *
54       * <p>This constructor is public to permit tools that require a JavaBean instance
55       * to operate.</p>
56       * @since 2.0
57       */
58      public SerializationUtils() {
59          super();
60      }
61  
62      // Clone
63      //-----------------------------------------------------------------------
64      /**
65       * <p>Deep clone an {@code Object} using serialization.</p>
66       *
67       * <p>This is many times slower than writing clone methods by hand
68       * on all objects in your object graph. However, for complex object
69       * graphs, or for those that don't support deep cloning this can
70       * be a simple alternative implementation. Of course all the objects
71       * must be {@code Serializable}.</p>
72       *
73       * @param <T> the type of the object involved
74       * @param object  the {@code Serializable} object to clone
75       * @return the cloned object
76       * @throws SerializationException (runtime) if the serialization fails
77       */
78      public static <T extends Serializable> T clone(final T object) {
79          if (object == null) {
80              return null;
81          }
82          final byte[] objectData = serialize(object);
83          final ByteArrayInputStream bais = new ByteArrayInputStream(objectData);
84  
85          ClassLoaderAwareObjectInputStream in = null;
86          try {
87              // stream closed in the finally
88              in = new ClassLoaderAwareObjectInputStream(bais, object.getClass().getClassLoader());
89              /*
90               * when we serialize and deserialize an object,
91               * it is reasonable to assume the deserialized object
92               * is of the same type as the original serialized object
93               */
94              @SuppressWarnings("unchecked") // see above
95              final
96              T readObject = (T) in.readObject();
97              return readObject;
98  
99          } 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     /**
115      * Performs a serialization roundtrip. Serializes and deserializes the given object, great for testing objects that
116      * implement {@link Serializable}.
117      *
118      * @param <T>
119      *           the type of the object involved
120      * @param msg
121      *            the object to roundtrip
122      * @return the serialized and deseralized object
123      * @since 3.3
124      */
125     public static <T extends Serializable> T roundtrip(final T msg) {
126         return SerializationUtils.deserialize(SerializationUtils.serialize(msg));
127     }
128 
129     // Serialize
130     //-----------------------------------------------------------------------
131     /**
132      * <p>Serializes an {@code Object} to the specified stream.</p>
133      *
134      * <p>The stream will be closed once the object is written.
135      * This avoids the need for a finally clause, and maybe also exception
136      * handling, in the application code.</p>
137      *
138      * <p>The stream passed in is not buffered internally within this method.
139      * This is the responsibility of your application if desired.</p>
140      *
141      * @param obj  the object to serialize to bytes, may be null
142      * @param outputStream  the stream to write to, must not be null
143      * @throws IllegalArgumentException if {@code outputStream} is {@code null}
144      * @throws SerializationException (runtime) if the serialization fails
145      */
146     public static void serialize(final Serializable obj, final OutputStream outputStream) {
147         if (outputStream == null) {
148             throw new IllegalArgumentException("The OutputStream must not be null");
149         }
150         ObjectOutputStream out = null;
151         try {
152             // stream closed in the finally
153             out = new ObjectOutputStream(outputStream);
154             out.writeObject(obj);
155 
156         } catch (final IOException ex) {
157             throw new SerializationException(ex);
158         } finally {
159             try {
160                 if (out != null) {
161                     out.close();
162                 }
163             } catch (final IOException ex) { // NOPMD
164                 // ignore close exception
165             }
166         }
167     }
168 
169     /**
170      * <p>Serializes an {@code Object} to a byte array for
171      * storage/serialization.</p>
172      *
173      * @param obj  the object to serialize to bytes
174      * @return a byte[] with the converted Serializable
175      * @throws SerializationException (runtime) if the serialization fails
176      */
177     public static byte[] serialize(final Serializable obj) {
178         final ByteArrayOutputStream baos = new ByteArrayOutputStream(512);
179         serialize(obj, baos);
180         return baos.toByteArray();
181     }
182 
183     // Deserialize
184     //-----------------------------------------------------------------------
185     /**
186      * <p>
187      * Deserializes an {@code Object} from the specified stream.
188      * </p>
189      * 
190      * <p>
191      * The stream will be closed once the object is written. This avoids the need for a finally clause, and maybe also
192      * exception handling, in the application code.
193      * </p>
194      * 
195      * <p>
196      * The stream passed in is not buffered internally within this method. This is the responsibility of your
197      * application if desired.
198      * </p>
199      * 
200      * <p>
201      * If the call site incorrectly types the return value, a {@link ClassCastException} is thrown from the call site.
202      * Without Generics in this declaration, the call site must type cast and can cause the same ClassCastException.
203      * Note that in both cases, the ClassCastException is in the call site, not in this method.
204      * </p>
205      *
206      * @param <T>  the object type to be deserialized
207      * @param inputStream
208      *            the serialized object input stream, must not be null
209      * @return the deserialized object
210      * @throws IllegalArgumentException
211      *             if {@code inputStream} is {@code null}
212      * @throws SerializationException
213      *             (runtime) if the serialization fails
214      */
215     public static <T> T deserialize(final InputStream inputStream) {
216         if (inputStream == null) {
217             throw new IllegalArgumentException("The InputStream must not be null");
218         }
219         ObjectInputStream in = null;
220         try {
221             // stream closed in the finally
222             in = new ObjectInputStream(inputStream);
223             @SuppressWarnings("unchecked") // may fail with CCE if serialised form is incorrect
224             final T obj = (T) in.readObject();
225             return obj;
226 
227         } catch (final ClassCastException ex) {
228             throw new SerializationException(ex);
229         } catch (final ClassNotFoundException ex) {
230             throw new SerializationException(ex);
231         } catch (final IOException ex) {
232             throw new SerializationException(ex);
233         } finally {
234             try {
235                 if (in != null) {
236                     in.close();
237                 }
238             } catch (final IOException ex) { // NOPMD
239                 // ignore close exception
240             }
241         }
242     }
243 
244     /**
245      * <p>
246      * Deserializes a single {@code Object} from an array of bytes.
247      * </p>
248      * 
249      * <p>
250      * If the call site incorrectly types the return value, a {@link ClassCastException} is thrown from the call site.
251      * Without Generics in this declaration, the call site must type cast and can cause the same ClassCastException.
252      * Note that in both cases, the ClassCastException is in the call site, not in this method.
253      * </p>
254      * 
255      * @param <T>  the object type to be deserialized
256      * @param objectData
257      *            the serialized object, must not be null
258      * @return the deserialized object
259      * @throws IllegalArgumentException
260      *             if {@code objectData} is {@code null}
261      * @throws SerializationException
262      *             (runtime) if the serialization fails
263      */
264     public static <T> T deserialize(final byte[] objectData) {
265         if (objectData == null) {
266             throw new IllegalArgumentException("The byte[] must not be null");
267         }
268         return SerializationUtils.<T>deserialize(new ByteArrayInputStream(objectData));
269     }
270 
271     /**
272      * <p>Custom specialization of the standard JDK {@link java.io.ObjectInputStream}
273      * that uses a custom  <code>ClassLoader</code> to resolve a class.
274      * If the specified <code>ClassLoader</code> is not able to resolve the class,
275      * the context classloader of the current thread will be used.
276      * This way, the standard deserialization work also in web-application
277      * containers and application servers, no matter in which of the
278      * <code>ClassLoader</code> the particular class that encapsulates
279      * serialization/deserialization lives. </p>
280      * 
281      * <p>For more in-depth information about the problem for which this
282      * class here is a workaround, see the JIRA issue LANG-626. </p>
283      */
284      static class ClassLoaderAwareObjectInputStream extends ObjectInputStream {
285         private static final Map<String, Class<?>> primitiveTypes = 
286                 new HashMap<String, Class<?>>();
287         private final ClassLoader classLoader;
288         
289         /**
290          * Constructor.
291          * @param in The <code>InputStream</code>.
292          * @param classLoader classloader to use
293          * @throws IOException if an I/O error occurs while reading stream header.
294          * @see java.io.ObjectInputStream
295          */
296         public ClassLoaderAwareObjectInputStream(final InputStream in, final ClassLoader classLoader) throws IOException {
297             super(in);
298             this.classLoader = classLoader;
299 
300             primitiveTypes.put("byte", byte.class);
301             primitiveTypes.put("short", short.class);
302             primitiveTypes.put("int", int.class);
303             primitiveTypes.put("long", long.class);
304             primitiveTypes.put("float", float.class);
305             primitiveTypes.put("double", double.class);
306             primitiveTypes.put("boolean", boolean.class);
307             primitiveTypes.put("char", char.class);
308             primitiveTypes.put("void", void.class);
309         }
310 
311         /**
312          * Overriden version that uses the parametrized <code>ClassLoader</code> or the <code>ClassLoader</code>
313          * of the current <code>Thread</code> to resolve the class.
314          * @param desc An instance of class <code>ObjectStreamClass</code>.
315          * @return A <code>Class</code> object corresponding to <code>desc</code>.
316          * @throws IOException Any of the usual Input/Output exceptions.
317          * @throws ClassNotFoundException If class of a serialized object cannot be found.
318          */
319         @Override
320         protected Class<?> resolveClass(final ObjectStreamClass desc) throws IOException, ClassNotFoundException {
321             final String name = desc.getName();
322             try {
323                 return Class.forName(name, false, classLoader);
324             } catch (final ClassNotFoundException ex) {
325                 try {
326                     return Class.forName(name, false, Thread.currentThread().getContextClassLoader());
327                 } catch (final ClassNotFoundException cnfe) {
328                     final Class<?> cls = primitiveTypes.get(name);
329                     if (cls != null) {
330                         return cls;
331                     } else {
332                         throw cnfe;
333                     }
334                 }
335             }
336         }
337 
338     }
339 
340 }