J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2006 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any 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}<tt>("getProxySelector")</tt> |
| 87 | * @see #setDefault(ProxySelector) |
| 88 | * @return the system-wide <code>ProxySelector</code> |
| 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</code> to unset the proxy selector. |
| 106 | * |
| 107 | * @throws SecurityException |
| 108 | * If a security manager has been installed and it denies |
| 109 | * {@link NetPermission}<tt>("setProxySelector")</tt> |
| 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>ftp URI for ftp connections</LI> |
| 131 | * <LI><code>socket://host:port</code><br> |
| 132 | * for tcp client sockets connections</LI> |
| 133 | * </UL> |
| 134 | * |
| 135 | * @param uri |
| 136 | * The URI that a connection is required to |
| 137 | * |
| 138 | * @return a List of Proxies. Each element in the |
| 139 | * the List is of type |
| 140 | * {@link java.net.Proxy Proxy}; |
| 141 | * when no proxy is available, the list will |
| 142 | * contain one element of type |
| 143 | * {@link java.net.Proxy Proxy} |
| 144 | * that represents a direct connection. |
| 145 | * @throws IllegalArgumentException if the argument is null |
| 146 | */ |
| 147 | public abstract List<Proxy> select(URI uri); |
| 148 | |
| 149 | /** |
| 150 | * Called to indicate that a connection could not be established |
| 151 | * to a proxy/socks server. An implementation of this method can |
| 152 | * temporarily remove the proxies or reorder the sequence of |
| 153 | * proxies returned by {@link #select(URI)}, using the address |
| 154 | * and the IOException caught when trying to connect. |
| 155 | * |
| 156 | * @param uri |
| 157 | * The URI that the proxy at sa failed to serve. |
| 158 | * @param sa |
| 159 | * The socket address of the proxy/SOCKS server |
| 160 | * |
| 161 | * @param ioe |
| 162 | * The I/O exception thrown when the connect failed. |
| 163 | * @throws IllegalArgumentException if either argument is null |
| 164 | */ |
| 165 | public abstract void connectFailed(URI uri, SocketAddress sa, IOException ioe); |
| 166 | } |