Class ProxySelector

java.lang.Object

java.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 setDefault method. The currently registered proxy selector can be retrieved by calling getDefault method.

When a proxy selector is registered, for instance, a subclass of URLConnection class should call the select method for each URL request so that the proxy selector can decide if a direct, or proxied connection should be used. The 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 connectFailed method to notify the proxy selector that the proxy server is unavailable.

The default proxy selector does enforce a set of System Properties related to proxy settings.

Since:

1.5

Constructor Summary

Constructors

Constructor	Description
ProxySelector()	Constructor for subclasses to call.

Method Summary

Modifier and Type	Method	Description
abstract void	connectFailed(URI uri, SocketAddress sa, IOException ioe)	Called to indicate that a connection could not be established to a proxy/socks server.
static ProxySelector	getDefault()	Gets the system-wide proxy selector.
static ProxySelector	of(InetSocketAddress proxyAddress)	Returns a ProxySelector which uses the given proxy address for all HTTP and HTTPS requests.
abstract List<Proxy>	select(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.
static void	setDefault(ProxySelector ps)	Sets (or unsets) the system-wide proxy selector.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

ProxySelector

public ProxySelector()

Constructor for subclasses to call.

Method Details

getDefault

public static ProxySelector getDefault()

Gets the system-wide proxy selector.

Returns:

the system-wide ProxySelector

Since:

1.5

See Also:

• setDefault(ProxySelector)

setDefault

public static void setDefault(ProxySelector ps)

Sets (or unsets) the system-wide proxy selector. Note: non-standard protocol handlers may ignore this setting.

Parameters:

ps - The HTTP proxy selector, or null to unset the proxy selector.

Since:

1.5

See Also:

• getDefault()

select

public abstract List<Proxy> select(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 follows:

• http URI for http connections
• https URI for https connections
• socket://host:port
  for tcp client sockets connections

Parameters:

uri - The URI that a connection is required to

Returns:

a List of Proxies. Each element in the List is of type Proxy; when no proxy is available, the list will contain one element of type Proxy that represents a direct connection.

Throws:

IllegalArgumentException - if the argument is null or if the protocol or host cannot be determined from the provided uri

connectFailed

public abstract void connectFailed(URI uri,
 SocketAddress sa,
 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(URI), using the address and the IOException caught when trying to connect.

Parameters:

uri - The URI that the proxy at sa failed to serve.

sa - The socket address of the proxy/SOCKS server

ioe - The I/O exception thrown when the connect failed.

Throws:

IllegalArgumentException - if either argument is null

of

public static ProxySelector of(InetSocketAddress proxyAddress)

Returns a ProxySelector which uses the given proxy address for all HTTP and HTTPS requests. If proxyAddress is null then proxying is disabled.

Parameters:

proxyAddress - The address of the proxy

Returns:

a ProxySelector

Since:

9