1/*
2 * Copyright (c) 2000, 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
26package com.sun.jndi.url.dns;
27
28
29import java.util.Hashtable;
30
31import javax.naming.*;
32import javax.naming.spi.ObjectFactory;
33
34
35/**
36 * A DNS URL context factory creates contexts that can resolve names
37 * that are DNS pseudo-URLs.
38 * In addition, if given a specific DNS URL (or an array of them), the
39 * factory will resolve all the way to the named context.
40 * See com.sun.jndi.dns.DnsUrl for a description of the URL format.
41 *
42 * @author Scott Seligman
43 */
44
45
46public class dnsURLContextFactory implements ObjectFactory {
47
48    public Object getObjectInstance(Object urlInfo, Name name,
49                                    Context nameCtx, Hashtable<?,?> env)
50            throws NamingException {
51
52        if (urlInfo == null) {
53            return (new dnsURLContext(env));
54        } else if (urlInfo instanceof String) {
55            return getUsingURL((String) urlInfo, env);
56        } else if (urlInfo instanceof String[]) {
57            return getUsingURLs((String[]) urlInfo, env);
58        } else {
59            throw (new ConfigurationException(
60                    "dnsURLContextFactory.getObjectInstance: " +
61                    "argument must be a DNS URL String or an array of them"));
62        }
63    }
64
65    private static Object getUsingURL(String url, Hashtable<?,?> env)
66            throws NamingException {
67
68        dnsURLContext urlCtx = new dnsURLContext(env);
69        try {
70            return urlCtx.lookup(url);
71        } finally {
72            urlCtx.close();
73        }
74    }
75
76    /*
77     * Try each URL until lookup() succeeds for one of them.
78     * If all URLs fail, throw one of the exceptions arbitrarily.
79     * Not pretty, but potentially more informative than returning null.
80     */
81    private static Object getUsingURLs(String[] urls, Hashtable<?,?> env)
82            throws NamingException {
83
84        if (urls.length == 0) {
85            throw (new ConfigurationException(
86                    "dnsURLContextFactory: empty URL array"));
87        }
88        dnsURLContext urlCtx = new dnsURLContext(env);
89        try {
90            NamingException ne = null;
91            for (int i = 0; i < urls.length; i++) {
92                try {
93                    return urlCtx.lookup(urls[i]);
94                } catch (NamingException e) {
95                    ne = e;
96                }
97            }
98            throw ne;   // failure:  throw one of the exceptions caught
99        } finally {
100            urlCtx.close();
101        }
102    }
103}
104