1 /*
2 * Copyright (c) 2003, 2013, 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 java.net;
27
28 import java.io.IOException;
29 import java.util.List;
30 import sun.security.util.SecurityConstants;
31
32 /**
33 * Selects the proxy server to use, if any, when connecting to the
34 * network resource referenced by a URL. A proxy selector is a
35 * concrete sub-class of this class and is registered by invoking the
36 * {@link java.net.ProxySelector#setDefault setDefault} method. The
37 * currently registered proxy selector can be retrieved by calling
38 * {@link java.net.ProxySelector#getDefault getDefault} method.
39 *
40 * <p> When a proxy selector is registered, for instance, a subclass
41 * of URLConnection class should call the {@link #select select}
42 * method for each URL request so that the proxy selector can decide
43 * if a direct, or proxied connection should be used. The {@link
44 * #select select} method returns an iterator over a collection with
45 * the preferred connection approach.
46 *
47 * <p> If a connection cannot be established to a proxy (PROXY or
48 * SOCKS) servers then the caller should call the proxy selector's
49 * {@link #connectFailed connectFailed} method to notify the proxy
50 * selector that the proxy server is unavailable. </p>
51 *
52 * <P>The default proxy selector does enforce a
53 * <a href="doc-files/net-properties.html#Proxies">set of System Properties</a>
54 * related to proxy settings.</P>
55 *
56 * @author Yingxian Wang
57 * @author Jean-Christophe Collet
58 * @since 1.5
59 */
60 public abstract class ProxySelector {
61 /**
62 * The system wide proxy selector that selects the proxy server to
63 * use, if any, when connecting to a remote object referenced by
64 * an URL.
65 *
66 * @see #setDefault(ProxySelector)
67 */
68 private static ProxySelector theProxySelector;
69
70 static {
71 try {
72 Class<?> c = Class.forName("sun.net.spi.DefaultProxySelector");
73 if (c != null && ProxySelector.class.isAssignableFrom(c)) {
74 theProxySelector = (ProxySelector) c.newInstance();
75 }
76 } catch (Exception e) {
77 theProxySelector = null;
78 }
79 }
80
81 /**
82 * Gets the system-wide proxy selector.
83 *
84 * @throws SecurityException
85 * If a security manager has been installed and it denies
86 * {@link NetPermission}{@code ("getProxySelector")}
87 * @see #setDefault(ProxySelector)
88 * @return the system-wide {@code ProxySelector}
89 * @since 1.5
90 */
91 public static ProxySelector getDefault() {
92 SecurityManager sm = System.getSecurityManager();
93 if (sm != null) {
94 sm.checkPermission(SecurityConstants.GET_PROXYSELECTOR_PERMISSION);
95 }
96 return theProxySelector;
97 }
98
99 /**
100 * Sets (or unsets) the system-wide proxy selector.
101 *
102 * Note: non-standard protocol handlers may ignore this setting.
103 *
104 * @param ps The HTTP proxy selector, or
105 * {@code null} to unset the proxy selector.
106 *
107 * @throws SecurityException
108 * If a security manager has been installed and it denies
109 * {@link NetPermission}{@code ("setProxySelector")}
110 *
111 * @see #getDefault()
112 * @since 1.5
113 */
114 public static void setDefault(ProxySelector ps) {
115 SecurityManager sm = System.getSecurityManager();
116 if (sm != null) {
117 sm.checkPermission(SecurityConstants.SET_PROXYSELECTOR_PERMISSION);
118 }
119 theProxySelector = ps;
120 }
121
122 /**
123 * Selects all the applicable proxies based on the protocol to
124 * access the resource with and a destination address to access
125 * the resource at.
126 * The format of the URI is defined as follow:
127 * <UL>
128 * <LI>http URI for http connections</LI>
129 * <LI>https URI for https connections
130 * <LI>{@code socket://host:port}<br>
131 * for tcp client sockets connections</LI>
132 * </UL>
133 *
134 * @param uri
135 * The URI that a connection is required to
136 *
137 * @return a List of Proxies. Each element in the
138 * the List is of type
139 * {@link java.net.Proxy Proxy};
140 * when no proxy is available, the list will
141 * contain one element of type
142 * {@link java.net.Proxy Proxy}
143 * that represents a direct connection.
144 * @throws IllegalArgumentException if the argument is null
145 */
146 public abstract List<Proxy> select(URI uri);
147
148 /**
149 * Called to indicate that a connection could not be established
150 * to a proxy/socks server. An implementation of this method can
151 * temporarily remove the proxies or reorder the sequence of
152 * proxies returned by {@link #select(URI)}, using the address
153 * and the IOException caught when trying to connect.
154 *
155 * @param uri
156 * The URI that the proxy at sa failed to serve.
157 * @param sa
158 * The socket address of the proxy/SOCKS server
159 *
160 * @param ioe
161 * The I/O exception thrown when the connect failed.
162 * @throws IllegalArgumentException if either argument is null
163 */
164 public abstract void connectFailed(URI uri, SocketAddress sa, IOException ioe);
165
166 /**
167 * Returns a ProxySelector which uses the given proxy address for all HTTP
168 * and HTTPS requests. If proxy is {@code null} then proxying is disabled.
169 *
170 * @param proxyAddress
171 * The address of the proxy
172 *
173 * @return a ProxySelector
174 *
175 * @since 9
176 */
177 public static ProxySelector of(InetSocketAddress proxyAddress) {
178 return new StaticProxySelector(proxyAddress);
179 }
180
181 static class StaticProxySelector extends ProxySelector {
182 private static final List<Proxy> NO_PROXY_LIST = List.of(Proxy.NO_PROXY);
183 final List<Proxy> list;
184
185 StaticProxySelector(InetSocketAddress address){
186 Proxy p;
187 if (address == null) {
188 p = Proxy.NO_PROXY;
189 } else {
190 p = new Proxy(Proxy.Type.HTTP, address);
191 }
192 list = List.of(p);
193 }
194
195 @Override
196 public void connectFailed(URI uri, SocketAddress sa, IOException e) {
197 /* ignore */
198 }
199
200 @Override
201 public synchronized List<Proxy> select(URI uri) {
202 String scheme = uri.getScheme().toLowerCase();
203 if (scheme.equals("http") || scheme.equals("https")) {
204 return list;
205 } else {
206 return NO_PROXY_LIST;
207 }
208 }
209 }
210 }