/* |
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* Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package java.net; |
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import java.io.IOException; |
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import java.util.List; |
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import sun.security.util.SecurityConstants; |
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/** |
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* Selects the proxy server to use, if any, when connecting to the |
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* network resource referenced by a URL. A proxy selector is a |
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* concrete sub-class of this class and is registered by invoking the |
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* {@link java.net.ProxySelector#setDefault setDefault} method. The |
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* currently registered proxy selector can be retrieved by calling |
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* {@link java.net.ProxySelector#getDefault getDefault} method. |
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* |
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* <p> When a proxy selector is registered, for instance, a subclass |
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* of URLConnection class should call the {@link #select select} |
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* method for each URL request so that the proxy selector can decide |
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* if a direct, or proxied connection should be used. The {@link |
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* #select select} method returns an iterator over a collection with |
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* the preferred connection approach. |
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* |
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* <p> If a connection cannot be established to a proxy (PROXY or |
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* SOCKS) servers then the caller should call the proxy selector's |
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* {@link #connectFailed connectFailed} method to notify the proxy |
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* selector that the proxy server is unavailable. </p> |
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* |
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* <P>The default proxy selector does enforce a |
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* <a href="doc-files/net-properties.html#Proxies">set of System Properties</a> |
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* related to proxy settings.</P> |
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* |
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* @author Yingxian Wang |
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* @author Jean-Christophe Collet |
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* @since 1.5 |
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*/ |
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public abstract class ProxySelector { |
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/** |
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* The system wide proxy selector that selects the proxy server to |
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* use, if any, when connecting to a remote object referenced by |
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* an URL. |
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* |
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* @see #setDefault(ProxySelector) |
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*/ |
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private static volatile ProxySelector theProxySelector; |
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static { |
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try { |
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Class<?> c = Class.forName("sun.net.spi.DefaultProxySelector"); |
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if (c != null && ProxySelector.class.isAssignableFrom(c)) { |
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@SuppressWarnings("deprecation") |
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ProxySelector tmp = (ProxySelector) c.newInstance(); |
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theProxySelector = tmp; |
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} |
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} catch (Exception e) { |
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theProxySelector = null; |
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} |
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} |
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/** |
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* Constructor for subclasses to call. |
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*/ |
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public ProxySelector() {} |
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/** |
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* Gets the system-wide proxy selector. |
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* |
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* @throws SecurityException |
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* If a security manager has been installed and it denies |
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* {@link NetPermission}{@code ("getProxySelector")} |
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* @see #setDefault(ProxySelector) |
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* @return the system-wide {@code ProxySelector} |
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* @since 1.5 |
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*/ |
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public static ProxySelector getDefault() { |
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@SuppressWarnings("removal") |
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SecurityManager sm = System.getSecurityManager(); |
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if (sm != null) { |
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sm.checkPermission(SecurityConstants.GET_PROXYSELECTOR_PERMISSION); |
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} |
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return theProxySelector; |
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} |
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/** |
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* Sets (or unsets) the system-wide proxy selector. |
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* |
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* Note: non-standard protocol handlers may ignore this setting. |
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* |
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* @param ps The HTTP proxy selector, or |
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* {@code null} to unset the proxy selector. |
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* |
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* @throws SecurityException |
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* If a security manager has been installed and it denies |
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* {@link NetPermission}{@code ("setProxySelector")} |
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* |
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* @see #getDefault() |
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* @since 1.5 |
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*/ |
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public static void setDefault(ProxySelector ps) { |
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@SuppressWarnings("removal") |
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SecurityManager sm = System.getSecurityManager(); |
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if (sm != null) { |
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sm.checkPermission(SecurityConstants.SET_PROXYSELECTOR_PERMISSION); |
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} |
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theProxySelector = ps; |
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} |
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/** |
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* Selects all the applicable proxies based on the protocol to |
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* access the resource with and a destination address to access |
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* the resource at. |
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* The format of the URI is defined as follow: |
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* <UL> |
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* <LI>http URI for http connections</LI> |
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* <LI>https URI for https connections |
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* <LI>{@code socket://host:port}<br> |
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* for tcp client sockets connections</LI> |
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* </UL> |
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* |
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* @param uri |
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* The URI that a connection is required to |
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* |
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* @return a List of Proxies. Each element in |
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* the List is of type |
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* {@link java.net.Proxy Proxy}; |
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* when no proxy is available, the list will |
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* contain one element of type |
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* {@link java.net.Proxy Proxy} |
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* that represents a direct connection. |
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* @throws IllegalArgumentException if the argument is null or if |
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* the protocol or host cannot be determined from the provided |
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* {@code uri} |
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*/ |
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public abstract List<Proxy> select(URI uri); |
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/** |
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* Called to indicate that a connection could not be established |
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* to a proxy/socks server. An implementation of this method can |
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* temporarily remove the proxies or reorder the sequence of |
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* proxies returned by {@link #select(URI)}, using the address |
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* and the IOException caught when trying to connect. |
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* |
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* @param uri |
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* The URI that the proxy at sa failed to serve. |
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* @param sa |
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* The socket address of the proxy/SOCKS server |
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* |
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* @param ioe |
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* The I/O exception thrown when the connect failed. |
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* @throws IllegalArgumentException if either argument is null |
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*/ |
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public abstract void connectFailed(URI uri, SocketAddress sa, IOException ioe); |
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/** |
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* Returns a ProxySelector which uses the given proxy address for all HTTP |
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* and HTTPS requests. If proxy is {@code null} then proxying is disabled. |
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* |
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* @param proxyAddress |
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* The address of the proxy |
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* |
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* @return a ProxySelector |
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* |
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* @since 9 |
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*/ |
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public static ProxySelector of(InetSocketAddress proxyAddress) { |
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return new StaticProxySelector(proxyAddress); |
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} |
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static class StaticProxySelector extends ProxySelector { |
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private static final List<Proxy> NO_PROXY_LIST = List.of(Proxy.NO_PROXY); |
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final List<Proxy> list; |
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StaticProxySelector(InetSocketAddress address){ |
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Proxy p; |
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if (address == null) { |
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p = Proxy.NO_PROXY; |
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} else { |
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p = new Proxy(Proxy.Type.HTTP, address); |
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} |
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list = List.of(p); |
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} |
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@Override |
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public void connectFailed(URI uri, SocketAddress sa, IOException e) { |
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/* ignore */ |
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} |
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@Override |
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public synchronized List<Proxy> select(URI uri) { |
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String scheme = uri.getScheme().toLowerCase(); |
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if (scheme.equals("http") || scheme.equals("https")) { |
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return list; |
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} else { |
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return NO_PROXY_LIST; |
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} |
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} |
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} |
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} |