    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     */
    017    package org.apache.commons.lang3;
    018
    019    import java.io.ByteArrayInputStream;
    020    import java.io.ByteArrayOutputStream;
    021    import java.io.IOException;
    022    import java.io.InputStream;
    023    import java.io.ObjectInputStream;
    024    import java.io.ObjectOutputStream;
    025    import java.io.ObjectStreamClass;
    026    import java.io.OutputStream;
    027    import java.io.Serializable;
    028
    029    /**
    030     * <p>Assists with the serialization process and performs additional functionality based
    031     * on serialization.</p>
    032     * <p>
    033     * <ul>
    034     * <li>Deep clone using serialization
    035     * <li>Serialize managing finally and IOException
    036     * <li>Deserialize managing finally and IOException
    037     * </ul>
    038     *
    039     * <p>This class throws exceptions for invalid {@code null} inputs.
    040     * Each method documents its behaviour in more detail.</p>
    041     *
    042     * <p>#ThreadSafe#</p>
    043     * @since 1.0
    044     * @version $Id: SerializationUtils.java 1199718 2011-11-09 12:43:20Z sebb $
    045     */
    046    public class SerializationUtils {
    047
    048        /**
    049         * <p>SerializationUtils instances should NOT be constructed in standard programming.
    050         * Instead, the class should be used as {@code SerializationUtils.clone(object)}.</p>
    051         *
    052         * <p>This constructor is public to permit tools that require a JavaBean instance
    053         * to operate.</p>
    054         * @since 2.0
    055         */
    056        public SerializationUtils() {
    057            super();
    058        }
    059
    060        // Clone
    061        //-----------------------------------------------------------------------
    062        /**
    063         * <p>Deep clone an {@code Object} using serialization.</p>
    064         *
    065         * <p>This is many times slower than writing clone methods by hand
    066         * on all objects in your object graph. However, for complex object
    067         * graphs, or for those that don't support deep cloning this can
    068         * be a simple alternative implementation. Of course all the objects
    069         * must be {@code Serializable}.</p>
    070         *
    071         * @param <T> the type of the object involved
    072         * @param object  the {@code Serializable} object to clone
    073         * @return the cloned object
    074         * @throws SerializationException (runtime) if the serialization fails
    075         */
    076        public static <T extends Serializable> T clone(T object) {
    077            if (object == null) {
    078                return null;
    079            }
    080            byte[] objectData = serialize(object);
    081            ByteArrayInputStream bais = new ByteArrayInputStream(objectData);
    082
    083            ClassLoaderAwareObjectInputStream in = null;
    084            try {
    085                // stream closed in the finally
    086                in = new ClassLoaderAwareObjectInputStream(bais, object.getClass().getClassLoader());
    087                /*
    088                 * when we serialize and deserialize an object,
    089                 * it is reasonable to assume the deserialized object
    090                 * is of the same type as the original serialized object
    091                 */
    092                @SuppressWarnings("unchecked") // see above
    093                T readObject = (T) in.readObject();
    094                return readObject;
    095
    096            } catch (ClassNotFoundException ex) {
    097                throw new SerializationException("ClassNotFoundException while reading cloned object data", ex);
    098            } catch (IOException ex) {
    099                throw new SerializationException("IOException while reading cloned object data", ex);
    100            } finally {
    101                try {
    102                    if (in != null) {
    103                        in.close();
    104                    }
    105                } catch (IOException ex) {
    106                    throw new SerializationException("IOException on closing cloned object data InputStream.", ex);
    107                }
    108            }
    109        }
    110
    111        // Serialize
    112        //-----------------------------------------------------------------------
    113        /**
    114         * <p>Serializes an {@code Object} to the specified stream.</p>
    115         *
    116         * <p>The stream will be closed once the object is written.
    117         * This avoids the need for a finally clause, and maybe also exception
    118         * handling, in the application code.</p>
    119         *
    120         * <p>The stream passed in is not buffered internally within this method.
    121         * This is the responsibility of your application if desired.</p>
    122         *
    123         * @param obj  the object to serialize to bytes, may be null
    124         * @param outputStream  the stream to write to, must not be null
    125         * @throws IllegalArgumentException if {@code outputStream} is {@code null}
    126         * @throws SerializationException (runtime) if the serialization fails
    127         */
    128        public static void serialize(Serializable obj, OutputStream outputStream) {
    129            if (outputStream == null) {
    130                throw new IllegalArgumentException("The OutputStream must not be null");
    131            }
    132            ObjectOutputStream out = null;
    133            try {
    134                // stream closed in the finally
    135                out = new ObjectOutputStream(outputStream);
    136                out.writeObject(obj);
    137
    138            } catch (IOException ex) {
    139                throw new SerializationException(ex);
    140            } finally {
    141                try {
    142                    if (out != null) {
    143                        out.close();
    144                    }
    145                } catch (IOException ex) { // NOPMD
    146                    // ignore close exception
    147                }
    148            }
    149        }
    150
    151        /**
    152         * <p>Serializes an {@code Object} to a byte array for
    153         * storage/serialization.</p>
    154         *
    155         * @param obj  the object to serialize to bytes
    156         * @return a byte[] with the converted Serializable
    157         * @throws SerializationException (runtime) if the serialization fails
    158         */
    159        public static byte[] serialize(Serializable obj) {
    160            ByteArrayOutputStream baos = new ByteArrayOutputStream(512);
    161            serialize(obj, baos);
    162            return baos.toByteArray();
    163        }
    164
    165        // Deserialize
    166        //-----------------------------------------------------------------------
    167        /**
    168         * <p>Deserializes an {@code Object} from the specified stream.</p>
    169         *
    170         * <p>The stream will be closed once the object is written. This
    171         * avoids the need for a finally clause, and maybe also exception
    172         * handling, in the application code.</p>
    173         *
    174         * <p>The stream passed in is not buffered internally within this method.
    175         * This is the responsibility of your application if desired.</p>
    176         *
    177         * @param inputStream  the serialized object input stream, must not be null
    178         * @return the deserialized object
    179         * @throws IllegalArgumentException if {@code inputStream} is {@code null}
    180         * @throws SerializationException (runtime) if the serialization fails
    181         */
    182        public static Object deserialize(InputStream inputStream) {
    183            if (inputStream == null) {
    184                throw new IllegalArgumentException("The InputStream must not be null");
    185            }
    186            ObjectInputStream in = null;
    187            try {
    188                // stream closed in the finally
    189                in = new ObjectInputStream(inputStream);
    190                return in.readObject();
    191
    192            } catch (ClassNotFoundException ex) {
    193                throw new SerializationException(ex);
    194            } catch (IOException ex) {
    195                throw new SerializationException(ex);
    196            } finally {
    197                try {
    198                    if (in != null) {
    199                        in.close();
    200                    }
    201                } catch (IOException ex) { // NOPMD
    202                    // ignore close exception
    203                }
    204            }
    205        }
    206
    207        /**
    208         * <p>Deserializes a single {@code Object} from an array of bytes.</p>
    209         *
    210         * @param objectData  the serialized object, must not be null
    211         * @return the deserialized object
    212         * @throws IllegalArgumentException if {@code objectData} is {@code null}
    213         * @throws SerializationException (runtime) if the serialization fails
    214         */
    215        public static Object deserialize(byte[] objectData) {
    216            if (objectData == null) {
    217                throw new IllegalArgumentException("The byte[] must not be null");
    218            }
    219            ByteArrayInputStream bais = new ByteArrayInputStream(objectData);
    220            return deserialize(bais);
    221        }
    222
    223        /**
    224         * <p>Custom specialization of the standard JDK {@link java.io.ObjectInputStream}
    225         * that uses a custom  <code>ClassLoader</code> to resolve a class.
    226         * If the specified <code>ClassLoader</code> is not able to resolve the class,
    227         * the context classloader of the current thread will be used.
    228         * This way, the standard deserialization work also in web-application
    229         * containers and application servers, no matter in which of the
    230         * <code>ClassLoader</code> the particular class that encapsulates
    231         * serialization/deserialization lives. </p>
    232         *
    233         * <p>For more in-depth information about the problem for which this
    234         * class here is a workaround, see the JIRA issue LANG-626. </p>
    235         */
    236         static class ClassLoaderAwareObjectInputStream extends ObjectInputStream {
    237            private ClassLoader classLoader;
    238
    239            /**
    240             * Constructor.
    241             * @param in The <code>InputStream</code>.
    242             * @param classLoader classloader to use
    243             * @throws IOException if an I/O error occurs while reading stream header.
    244             * @see java.io.ObjectInputStream
    245             */
    246            public ClassLoaderAwareObjectInputStream(InputStream in, ClassLoader classLoader) throws IOException {
    247                super(in);
    248                this.classLoader = classLoader;
    249            }
    250
    251            /**
    252             * Overriden version that uses the parametrized <code>ClassLoader</code> or the <code>ClassLoader</code>
    253             * of the current <code>Thread</code> to resolve the class.
    254             * @param desc An instance of class <code>ObjectStreamClass</code>.
    255             * @return A <code>Class</code> object corresponding to <code>desc</code>.
    256             * @throws IOException Any of the usual Input/Output exceptions.
    257             * @throws ClassNotFoundException If class of a serialized object cannot be found.
    258             */
    259            @Override
    260            protected Class<?> resolveClass(ObjectStreamClass desc) throws IOException, ClassNotFoundException {
    261                String name = desc.getName();
    262                try {
    263                    return Class.forName(name, false, classLoader);
    264                } catch (ClassNotFoundException ex) {
    265                    return Class.forName(name, false, Thread.currentThread().getContextClassLoader());
    266                }
    267            }
    268
    269        }
    270
    271    }