1/*
2 * Copyright (c) 2003, 2014, 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
26package javax.sql.rowset.serial;
27
28import java.sql.*;
29import java.io.*;
30import java.net.URL;
31
32
33/**
34 * A serialized mapping in the Java programming language of an SQL
35 * <code>DATALINK</code> value. A <code>DATALINK</code> value
36 * references a file outside of the underlying data source that the
37 * data source manages.
38 * <P>
39 * <code>RowSet</code> implementations can use the method <code>RowSet.getURL</code>
40 * to retrieve a <code>java.net.URL</code> object, which can be used
41 * to manipulate the external data.
42 * <pre>
43 *      java.net.URL url = rowset.getURL(1);
44 * </pre>
45 *
46 * <h3> Thread safety </h3>
47 *
48 * A SerialDatalink is not safe for use by multiple concurrent threads.  If a
49 * SerialDatalink is to be used by more than one thread then access to the
50 * SerialDatalink should be controlled by appropriate synchronization.
51 *
52 * @since 1.5
53 */
54public class SerialDatalink implements Serializable, Cloneable {
55
56    /**
57     * The extracted URL field retrieved from the DATALINK field.
58     * @serial
59     */
60    private URL url;
61
62    /**
63     * The SQL type of the elements in this <code>SerialDatalink</code>
64     * object.  The type is expressed as one of the constants from the
65     * class <code>java.sql.Types</code>.
66     * @serial
67     */
68    private int baseType;
69
70    /**
71     * The type name used by the DBMS for the elements in the SQL
72     * <code>DATALINK</code> value that this SerialDatalink object
73     * represents.
74     * @serial
75     */
76    private String baseTypeName;
77
78    /**
79      * Constructs a new <code>SerialDatalink</code> object from the given
80      * <code>java.net.URL</code> object.
81      *
82      * @param url the {@code URL} to create the {@code SerialDataLink} from
83      * @throws SerialException if url parameter is a null
84      */
85    public SerialDatalink(URL url) throws SerialException {
86        if (url == null) {
87            throw new SerialException("Cannot serialize empty URL instance");
88        }
89        this.url = url;
90    }
91
92    /**
93     * Returns a new URL that is a copy of this <code>SerialDatalink</code>
94     * object.
95     *
96     * @return a copy of this <code>SerialDatalink</code> object as a
97     * <code>URL</code> object in the Java programming language.
98     * @throws SerialException if the <code>URL</code> object cannot be de-serialized
99     */
100    public URL getDatalink() throws SerialException {
101
102        URL aURL = null;
103
104        try {
105            aURL = new URL((this.url).toString());
106        } catch (java.net.MalformedURLException e) {
107            throw new SerialException("MalformedURLException: " + e.getMessage());
108        }
109        return aURL;
110    }
111
112    /**
113     * Compares this {@code SerialDatalink} to the specified object.
114     * The result is {@code true} if and only if the argument is not
115     * {@code null} and is a {@code SerialDatalink} object whose URL is
116     * identical to this object's URL
117     *
118     * @param  obj The object to compare this {@code SerialDatalink} against
119     *
120     * @return  {@code true} if the given object represents a {@code SerialDatalink}
121     *          equivalent to this SerialDatalink, {@code false} otherwise
122     *
123     */
124    public boolean equals(Object obj) {
125        if (this == obj) {
126            return true;
127        }
128        if (obj instanceof SerialDatalink) {
129            SerialDatalink sdl = (SerialDatalink) obj;
130            return url.equals(sdl.url);
131        }
132        return false;
133    }
134
135    /**
136     * Returns a hash code for this {@code SerialDatalink}. The hash code for a
137     * {@code SerialDatalink} object is taken as the hash code of
138     * the {@code URL} it stores
139     *
140     * @return  a hash code value for this object.
141     */
142    public int hashCode() {
143        return 31 + url.hashCode();
144    }
145
146    /**
147     * Returns a clone of this {@code SerialDatalink}.
148     *
149     * @return  a clone of this SerialDatalink
150     */
151    public Object clone() {
152        try {
153            SerialDatalink sdl = (SerialDatalink) super.clone();
154            return sdl;
155        } catch (CloneNotSupportedException ex) {
156            // this shouldn't happen, since we are Cloneable
157            throw new InternalError();
158        }
159    }
160
161    /**
162     * readObject and writeObject are called to restore the state
163     * of the {@code SerialDatalink}
164     * from a stream. Note: we leverage the default Serialized form
165     */
166
167    /**
168     * The identifier that assists in the serialization of this
169     *  {@code SerialDatalink} object.
170     */
171    static final long serialVersionUID = 2826907821828733626L;
172}
173