1 /*
2 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.sql.rowset.serial;
27
28 import java.io.*;
29 import java.lang.reflect.*;
30 import javax.sql.rowset.RowSetWarning;
31
32 /**
33 * A serializable mapping in the Java programming language of an SQL
34 * <code>JAVA_OBJECT</code> value. Assuming the Java object
35 * implements the <code>Serializable</code> interface, this class simply wraps the
36 * serialization process.
37 * <P>
38 * If however, the serialization is not possible because
39 * the Java object is not immediately serializable, this class will
40 * attempt to serialize all non-static members to permit the object
41 * state to be serialized.
42 * Static or transient fields cannot be serialized; an attempt to serialize
43 * them will result in a <code>SerialException</code> object being thrown.
44 *
45 * @author Jonathan Bruce
46 */
47 public class SerialJavaObject implements Serializable, Cloneable {
48
49 /**
50 * Placeholder for object to be serialized.
51 */
52 private final Object obj;
53
54
55 /**
56 * Placeholder for all fields in the <code>JavaObject</code> being serialized.
57 */
58 private transient Field[] fields;
59
60 /**
61 * Constructor for <code>SerialJavaObject</code> helper class.
62 * <p>
63 *
64 * @param obj the Java <code>Object</code> to be serialized
65 * @throws SerialException if the object is found not to be serializable
66 */
67 public SerialJavaObject(Object obj) throws SerialException {
68
69 // if any static fields are found, an exception
70 // should be thrown
71
72
73 // get Class. Object instance should always be available
74 Class<?> c = obj.getClass();
75
76 // determine if object implements Serializable i/f
77 if (!(obj instanceof java.io.Serializable)) {
78 setWarning(new RowSetWarning("Warning, the object passed to the constructor does not implement Serializable"));
79 }
80
81 // can only determine public fields (obviously). If
82 // any of these are static, this should invalidate
83 // the action of attempting to persist these fields
84 // in a serialized form
85
86 boolean anyStaticFields = false;
87 fields = c.getFields();
88
89 for (int i = 0; i < fields.length; i++ ) {
90 if ( fields[i].getModifiers() == Modifier.STATIC ) {
91 anyStaticFields = true;
92 }
93 }
94
95
96 if (anyStaticFields) {
97 throw new SerialException("Located static fields in " +
98 "object instance. Cannot serialize");
99 }
100
101 this.obj = obj;
102 }
103
104 /**
105 * Returns an <code>Object</code> that is a copy of this <code>SerialJavaObject</code>
106 * object.
107 *
108 * @return a copy of this <code>SerialJavaObject</code> object as an
109 * <code>Object</code> in the Java programming language
110 * @throws SerialException if the instance is corrupt
111 */
112 public Object getObject() throws SerialException {
113 return this.obj;
114 }
115
116 /**
117 * Returns an array of <code>Field</code> objects that contains each
118 * field of the object that this helper class is serializing.
119 *
120 * @return an array of <code>Field</code> objects
121 * @throws SerialException if an error is encountered accessing
122 * the serialized object
123 */
124 public Field[] getFields() throws SerialException {
125 if (fields != null) {
126 Class<?> c = this.obj.getClass();
127 return c.getFields();
128 } else {
129 throw new SerialException("SerialJavaObject does not contain" +
130 " a serialized object instance");
131 }
132 }
133
134 /**
135 * The identifier that assists in the serialization of this
136 * <code>SerialJavaObject</code> object.
137 */
138 static final long serialVersionUID = -1465795139032831023L;
139
140 /**
141 * A container for the warnings issued on this <code>SerialJavaObject</code>
142 * object. When there are multiple warnings, each warning is chained to the
143 * previous warning.
144 */
145 java.util.Vector<RowSetWarning> chain;
146
147 /**
148 * Registers the given warning.
149 */
150 private void setWarning(RowSetWarning e) {
151 if (chain == null) {
152 chain = new java.util.Vector<RowSetWarning>();
153 }
154 chain.add(e);
155 }
156 }