FileDocCategorySizeDatePackage
ProxySelector.javaAPI DocJava SE 5 API5045Fri Aug 26 14:57:08 BST 2005java.net

ProxySelector

public abstract class ProxySelector extends Object
Selects the proxy server to use, if any, when connecting to the network resource referenced by a URL. A proxy selector is a concrete sub-class of this class and is registered by invoking the {@link java.net.ProxySelector#setDefault setDefault} method. The currently registered proxy selector can be retrieved by calling {@link java.net.ProxySelector#getDefault getDefault} method.

When a proxy selector is registered, for instance, a subclass of URLConnection class should call the {@link #select select} method for each URL request so that the proxy selector can decide if a direct, or proxied connection should be used. The {@link #select select} method returns an iterator over a collection with the preferred connection approach.

If a connection cannot be established to a proxy (PROXY or SOCKS) servers then the caller should call the proxy selector's {@link #connectFailed connectFailed} method to notify the proxy selector that the proxy server is unavailable.

version
1.3, 03/08/09
author
Yingxian Wang
author
Jean-Christophe Collet
since
1.5

Fields Summary
private static ProxySelector
theProxySelector
The system wide proxy selector that selects the proxy server to use, if any, when connecting to a remote object referenced by an URL.
Constructors Summary
Methods Summary
public abstract voidconnectFailed(java.net.URI uri, java.net.SocketAddress sa, java.io.IOException ioe)
Called to indicate that a connection could not be established to a proxy/socks server. An implementation of this method can temporarily remove the proxies or reorder the sequence of proxies returned by select(String, String), using the address and they kind of IOException given.

param
uri The URI that the proxy at sa failed to serve.
param
sa The socket address of the proxy/SOCKS server
param
ioe The I/O exception thrown when the connect failed.
throws
IllegalArgumentException if either argument is null

public static java.net.ProxySelectorgetDefault()
Gets the system-wide proxy selector.
throws
SecurityException
If a security manager has been installed and it denies
{@link NetPermission}("getProxySelector")
see
#setDefault(ProxySelector)
return
the system-wide ProxySelector
since
1.5
 
	try {
	    Class c = Class.forName("sun.net.spi.DefaultProxySelector");
	    if (c != null && ProxySelector.class.isAssignableFrom(c)) {
		theProxySelector = (ProxySelector) c.newInstance();
	    }
	} catch (Exception e) {
	    theProxySelector = null;
	}
    
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	    sm.checkPermission(SecurityConstants.GET_PROXYSELECTOR_PERMISSION);
	}
	return theProxySelector;
    
public abstract java.util.Listselect(java.net.URI uri)
Selects all the applicable proxies based on the protocol to
access the resource with and a destination address to access
the resource at.
The format of the URI is defined as follow:

    

  • http URI for http connections
    • 

  • https URI for https connections

  • ftp URI for ftp connections
    • 

  • socket://host:port
    
for tcp client sockets connections
    • 

param
uri
The URI that a connection is required to
return
a List of Proxies. Each element in the
the List is of type
{@link java.net.Proxy Proxy};
when no proxy is available, the list will
contain one element of type
{@link java.net.Proxy Proxy}
that represents a direct connection.
throws
IllegalArgumentException if either argument is null
public static voidsetDefault(java.net.ProxySelector ps)
Sets (or unsets) the system-wide proxy selector.

Note: non-standard procotol handlers may ignore this setting.
param
ps The HTTP proxy selector, or
null to unset the proxy selector.
throws
SecurityException
If a security manager has been installed and it denies
{@link NetPermission}("setProxySelector")
see
#getDefault()
since
1.5
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	    sm.checkPermission(SecurityConstants.SET_PROXYSELECTOR_PERMISSION);
	}
	theProxySelector = ps;