org.w3c.www.protocol.http.icp
Class ICPFilter

java.lang.Object
  org.w3c.www.protocol.http.icp.ICPFilter

All Implemented Interfaces:

PropertyMonitoring, PropRequestFilter, RequestFilter

public class ICPFilter
extends java.lang.Object
implements PropRequestFilter, PropertyMonitoring

Field Summary

static java.lang.String	CONFIG_P Properties - Our configuration file.
protected boolean	debug Our we in debug mode ?
static java.lang.String	DEBUG_P Properties - Our debug flag.
static java.lang.String	DISABLE_CACHE_P Properties - disable caching when fetching from a neighbour proxy.
protected boolean	disableCache Should we disablecaching when fetching through a proxy ?
protected java.util.Hashtable	friends Our senders, indexed by InetAddress.
protected org.w3c.www.protocol.http.icp.ICPReceiver	icp Our ICP engine.
static java.lang.String	PORT_P Properties - Our own UDP port number.
protected ObservableProperties	props The properties we are initialized from.
static java.lang.String	TIMEOUT_P Properties - Our default timeout value.
protected long	timeoutValue Our default timeout value for waiting for replies (in ms).

Constructor Summary

ICPFilter()

Method Summary

protected void	createICPSender(java.lang.String host, int dstport, java.lang.String http)
boolean	exceptionFilter(Request request, HttpException ex) This filter doesn't handle exceptions.
org.w3c.www.protocol.http.icp.ICPSender	getSender(java.net.InetAddress addr, int port) Get the sender object for the given InetAddress instance.
protected java.net.DatagramSocket	getSocket()
Reply	ingoingFilter(Request request) Our ingoingFilter method.
void	initialize(HttpManager manager) Initialize the ICP filter.
protected java.net.URL	locateProxy(org.w3c.www.protocol.http.icp.ICPReply reply) Locate the HTTP service of the proxy that has emitted that reply.
Reply	outgoingFilter(Request request, Reply reply) Our outgoingFilter does nothing (at all).
protected void	parseConfiguration() Parse the configuration file.
boolean	propertyChanged(java.lang.String name) The callback method, invoked when any property change occurs.
protected java.net.URL	runQuery(org.w3c.www.protocol.http.icp.ICPQuery query) Run the ICP query, and return the proxy we should go to.
protected int	sendQuery(org.w3c.www.protocol.http.icp.ICPQuery query) Send the given query to all our neighbors.
void	sync() This filter doesn't maintain dynamic state.

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG_P

public static final java.lang.String DEBUG_P

Properties - Our debug flag.

See Also:

Constant Field Values

CONFIG_P

public static final java.lang.String CONFIG_P

Properties - Our configuration file.

See Also:

Constant Field Values

PORT_P

public static final java.lang.String PORT_P

Properties - Our own UDP port number.

See Also:

Constant Field Values

TIMEOUT_P

public static final java.lang.String TIMEOUT_P

Properties - Our default timeout value.

See Also:

Constant Field Values

DISABLE_CACHE_P

public static final java.lang.String DISABLE_CACHE_P

Properties - disable caching when fetching from a neighbour proxy.

See Also:

Constant Field Values

props

protected ObservableProperties props

The properties we are initialized from.

icp

protected org.w3c.www.protocol.http.icp.ICPReceiver icp

Our ICP engine.

friends

protected java.util.Hashtable friends

Our senders, indexed by InetAddress.

timeoutValue

protected long timeoutValue

Our default timeout value for waiting for replies (in ms).

debug

protected boolean debug

Our we in debug mode ?

disableCache

protected boolean disableCache

Should we disablecaching when fetching through a proxy ?

Constructor Detail

ICPFilter

public ICPFilter()

Method Detail

propertyChanged

public boolean propertyChanged(java.lang.String name)

Description copied from interface: PropertyMonitoring

The callback method, invoked when any property change occurs.

Specified by:

propertyChanged in interface PropertyMonitoring

Parameters:

name - The name of the property that changed.

Returns:

A boolean, if true, accept the new property value, otherwise, reject it and reset the property to its old value.

getSocket

protected java.net.DatagramSocket getSocket()

createICPSender

protected void createICPSender(java.lang.String host,
                               int dstport,
                               java.lang.String http)
                        throws java.net.UnknownHostException,
                               java.net.MalformedURLException,
                               java.net.SocketException

Throws:

java.net.UnknownHostException

java.net.MalformedURLException

java.net.SocketException

parseConfiguration

protected void parseConfiguration()

Parse the configuration file.

getSender

public org.w3c.www.protocol.http.icp.ICPSender getSender(java.net.InetAddress addr,
                                                         int port)

Get the sender object for the given InetAddress instance.

Parameters:

addr - The InetAddress of the sender.

Returns:

An ICPSender instance, if available, null otherwise.

locateProxy

protected java.net.URL locateProxy(org.w3c.www.protocol.http.icp.ICPReply reply)

Locate the HTTP service of the proxy that has emitted that reply.

Parameters:

reply - The reply emitted by the host that alos host the HTTP service we are looking for.

Returns:

The URL of the proxy, or null if no matching proxy was found.

sendQuery

protected int sendQuery(org.w3c.www.protocol.http.icp.ICPQuery query)

Send the given query to all our neighbors.

Returns:

The number of times we emitted the query.

runQuery

protected java.net.URL runQuery(org.w3c.www.protocol.http.icp.ICPQuery query)

Run the ICP query, and return the proxy we should go to.

Parameters:

url - The URL we are looking for.

Returns:

The URL of the proxy we should go to for that URL, or null if none was found.

exceptionFilter

public boolean exceptionFilter(Request request,
                               HttpException ex)

This filter doesn't handle exceptions.

Specified by:

exceptionFilter in interface RequestFilter

Parameters:

request - The request that triggered the exception.

ex - The triggered exception.

Returns:

Always false.

ingoingFilter

public Reply ingoingFilter(Request request)

Our ingoingFilter method. This method emits (only for GET requestst currently) an ICP query to all our neighbors, and wait for either one of them to reply with a hit, or, our timeout value to expire.

If a hit reply is received, we then use the corresponding proxy to fullfill the request.

Specified by:

ingoingFilter in interface RequestFilter

Parameters:

request - The request that is about to be emitted.

Returns:

Always null.

outgoingFilter

public Reply outgoingFilter(Request request,
                            Reply reply)

Our outgoingFilter does nothing (at all).

Specified by:

outgoingFilter in interface RequestFilter

Parameters:

request - The request that has been processed.

reply - The original reply (from origin server)

Returns:

Always null.

sync

public void sync()

This filter doesn't maintain dynamic state.

Specified by:

sync in interface RequestFilter

initialize

public void initialize(HttpManager manager)
                throws PropRequestFilterException

Initialize the ICP filter. This is where we parse the configuration file in order to know about our neighbors. We then register ourself to the HTTP manager.

Specified by:

initialize in interface PropRequestFilter

Parameters:

manager - The HTTP manager.

Throws:

PropRequestFilterException - If the filter cannot launch its server part (listening for incomming ICP requests)