org.w3c.www.protocol.http
Class HttpBasicServer

java.lang.Object
  org.w3c.www.protocol.http.HttpServer
      org.w3c.www.protocol.http.HttpBasicServer

public class HttpBasicServer
extends HttpServer

The basic server class, to run requests. A server instance (ie an object conforming to the HttpServer interface is resposnsible for running all requests to a given host.

To do so, it manages a connnnection pool (ie a set of available connections) which it negotiates with the global HTTP manager. It keeps track of the connections it creates in order to serialize requests to the target server (when possible). In order to avoid deadlock due to implicit ordering of requests, a server that manages persistent (ie > 1.0) connections will always be able to open at least two connections to the same target.

Connections are kept track of by the server instance, which maintains at all point in time a list of idle connections. The way this is done may seem quite tricky, but beleive me, it's the best way I have found to handle it (there is here a typical deadlock situation - the same which is found in org.w3c.jigsaw.http.Client - due to the fact that the server instances need to be locked in order to change the connection pool, and at the same time each connection of the pool might have to notify the pool of some events. This can easily produce a deadlock...This situation is avoided here, by having the server locked only when appropriate...

Field Summary

protected int	conn_timeout The connectiontimeout for the socket
protected int	connid Connections management - Allocate a new connection for this server.
protected java.lang.String	host The host name of the server we handle.
protected HttpManager	manager Our central HTTP manager.
protected int	port The port number of the server we handle.
protected static int	RQ_HTTP10 Request mode - HTTP/1.0 with no keep-alive support.
protected static int	RQ_HTTP10_KA Request mode - HTTP/1.0 with keep-alive support.
protected static int	RQ_HTTP11 Request mode - Full HTTP/1.1 compliant mode.
protected static int	RQ_HTTP11_TS Request mode - Full two stage HTTP/1.1 compliant mode.
protected static int	RQ_UNKNOWN Request mode - Unknown target server.
protected int	timeout The timeout on the socket

Fields inherited from class org.w3c.www.protocol.http.HttpServer

state

Method Summary

protected org.w3c.www.protocol.http.HttpBasicConnection	allocateConnection()
void	deleteConnection(org.w3c.www.protocol.http.HttpConnection conn)
protected Reply	doRequest(org.w3c.www.protocol.http.HttpBasicConnection conn, Request request) Exceute given request on given conection, according to server.
protected org.w3c.www.protocol.http.HttpBasicConnection	getConnection() Connections management - Get an idle connection to run a request.
short	getMajorVersion() HttpServer implementation - Get this server's major version number.
short	getMinorVersion() HttpServer implementation - Get this server's minor version number.
java.lang.String	getProtocol() HttpServer implementation - Get this servers' protocol.
protected int	getRequestMode(Request request) Get the current mode of running request for that server.
protected Reply	http_unknown(org.w3c.www.protocol.http.HttpBasicConnection conn, Request request) Run that request, we don't know what server we have at the other end.
protected Reply	http10_ka_run(org.w3c.www.protocol.http.HttpBasicConnection conn, Request request) Run an HTTP/1.0 request that has support for keep alive.
protected Reply	http10_run(org.w3c.www.protocol.http.HttpBasicConnection conn, Request request) Run a simple HTTP/1.0 request.
protected Reply	http11_run(org.w3c.www.protocol.http.HttpBasicConnection conn, Request request) Run a fully HTTP/1.1 compliant request.
protected Reply	http11_ts_run(org.w3c.www.protocol.http.HttpBasicConnection conn, Request request) Run a two stage HTTP/1.1 compliant request.
void	initialize(HttpManager manager, org.w3c.www.protocol.http.HttpServerState state, java.lang.String host, int port, int timeout) HttpServer implementation - Initialize this server to its target.
void	initialize(HttpManager manager, org.w3c.www.protocol.http.HttpServerState state, java.lang.String host, int port, int timeout, int conn_timeout) HttpServer implementation - Initialize this server to its target.
protected void	interruptRequest(Request request) Interrupt given request, that was launched by ourself.
protected boolean	isTwoStage_10(Request request) Is this request a two stage request.
protected boolean	isTwoStage_11(Request request) Is this request a two stage request.
protected void	notifyObserver(RequestObserver obs, RequestEvent evt)
protected void	notifyObserver(RequestObserver obs, Request request, int code)
void	registerConnection(org.w3c.www.protocol.http.HttpConnection conn) Connections management - Register a connection as being idle.
Reply	runRequest(Request request) Run the given request in synchronous mode.
void	setConnTimeout(int conn_timeout) Set the connection timeout for the next connections
protected void	setHostAddr(java.net.InetAddress[] hostAddrs) set the inet addresses of this host, and timestamp it to avoid caching IPs forever
void	setTimeout(int timeout) Set the timeout for the next connections
java.lang.String	toString() Display this server into a String.
void	unregisterConnection(org.w3c.www.protocol.http.HttpConnection conn) Unregister a connection from the idle list.
protected void	updateHostAddr() check the validity of the host address if invalid, it will update the InetAddress associated with this host
protected void	updateServerInfo(Reply reply) A full round-trip has been run with the target server, update infos.

Methods inherited from class org.w3c.www.protocol.http.HttpServer

getState

Methods inherited from class java.lang.Object

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

Field Detail

RQ_HTTP11

protected static final int RQ_HTTP11

Request mode - Full HTTP/1.1 compliant mode.

See Also:

Constant Field Values

RQ_HTTP11_TS

protected static final int RQ_HTTP11_TS

Request mode - Full two stage HTTP/1.1 compliant mode.

See Also:

Constant Field Values

RQ_HTTP10

protected static final int RQ_HTTP10

Request mode - HTTP/1.0 with no keep-alive support.

See Also:

Constant Field Values

RQ_HTTP10_KA

protected static final int RQ_HTTP10_KA

Request mode - HTTP/1.0 with keep-alive support.

See Also:

Constant Field Values

RQ_UNKNOWN

protected static final int RQ_UNKNOWN

Request mode - Unknown target server.

See Also:

Constant Field Values

manager

protected HttpManager manager

Our central HTTP manager.

host

protected java.lang.String host

The host name of the server we handle.

port

protected int port

The port number of the server we handle.

timeout

protected int timeout

The timeout on the socket

conn_timeout

protected int conn_timeout

The connectiontimeout for the socket

connid

protected int connid

Connections management - Allocate a new connection for this server. The connection is bound to the next available IP address, so that we are able to round-robin on them. If one of the DNS advertized IP address fails, we just try the next one, until one of them succeed or all of them fail.

Method Detail

setHostAddr

protected void setHostAddr(java.net.InetAddress[] hostAddrs)

set the inet addresses of this host, and timestamp it to avoid caching IPs forever

Parameters:

hostAddrs, - an array of InetAddress

updateHostAddr

protected void updateHostAddr()
                       throws HttpException

check the validity of the host address if invalid, it will update the InetAddress associated with this host

Throws:

HttpException

getProtocol

public java.lang.String getProtocol()

HttpServer implementation - Get this servers' protocol.

Specified by:

getProtocol in class HttpServer

Returns:

A String encoding the protocol used to dialog with the target server.

getMajorVersion

public short getMajorVersion()

HttpServer implementation - Get this server's major version number.

Specified by:

getMajorVersion in class HttpServer

Returns:

The server's major number version, or -1 if still unknown.

getMinorVersion

public short getMinorVersion()

HttpServer implementation - Get this server's minor version number.

Specified by:

getMinorVersion in class HttpServer

Returns:

The server's minor number version, or -1 if still unknown.

setTimeout

public void setTimeout(int timeout)

Set the timeout for the next connections

Specified by:

setTimeout in class HttpServer

Parameters:

timeout - The timeout in milliseconds

setConnTimeout

public void setConnTimeout(int conn_timeout)

Set the connection timeout for the next connections

Specified by:

setConnTimeout in class HttpServer

Parameters:

timeout - The timeout in milliseconds

allocateConnection

protected org.w3c.www.protocol.http.HttpBasicConnection allocateConnection()
                                                                    throws java.io.IOException

Throws:

java.io.IOException

registerConnection

public void registerConnection(org.w3c.www.protocol.http.HttpConnection conn)

Connections management - Register a connection as being idle. When a connection is created, or when it becomes idle again (after having been used to handle a request), it has to be registered back to the idle list of connection for the server. All connections contained in this idle list are candidates for being elected to handle some pending or incoming request to the host we manager.

Parameters:

conn - The connection that is now idle.

unregisterConnection

public void unregisterConnection(org.w3c.www.protocol.http.HttpConnection conn)

Unregister a connection from the idle list. Unregistering a connection means that the server shouldn't keep track of it any more. This can happen in two situations:

• The connection won't be reusable, so there is no point for the server to try to keep track of it. In this case, the connection is forgotten, and the caller will terminate it by invoking the connection's input stream close method.
• The connection has successfully handle a connection, and the connection is about to be reused. During the time of the request processing, the server looses track of this connection, which will register itself again when back to idle.

  Parameters:

  conn - The connection to unregister from the idle list.

deleteConnection

public void deleteConnection(org.w3c.www.protocol.http.HttpConnection conn)

getConnection

protected org.w3c.www.protocol.http.HttpBasicConnection getConnection()
                                                               throws java.io.IOException

Connections management - Get an idle connection to run a request. The server has been asked to run a new request, and it now wants a connection to run it on. This method will try various ways of aqcuiring a connection:

• It will look for an idle connection.
• It will then try to negotiate with the HTTP manager the creation of a new connection to the target server.
• If this fails too, it will just wait until a connection becomes available.

The connection returned is marked for use (ie it is unregistered from the idle connection list), it is up to the caller to make sure that if possible, the connection registers itself again to the idle list after the processing is done.

This method can return null to indicate to the caller that it should try again, in the hope that the target server has multiple (different) IP addresses.

Returns:

A connection marked in use, and which should be marked as idle after the processing it is use for is done, or null if a fresh connection cannot be established.

Throws:

java.io.IOException

toString

public java.lang.String toString()

Display this server into a String.

Overrides:

toString in class java.lang.Object

Returns:

A String based representation of the server object.

updateServerInfo

protected void updateServerInfo(Reply reply)

A full round-trip has been run with the target server, update infos. Each server instance maintains a set of informations to be reused if needed when recontacting the server later. After a full round trip has been performed with the server, it is time to update the target server version number, and keeps-alive flag.

Parameters:

reply - The first reply we got from this server.

initialize

public void initialize(HttpManager manager,
                       org.w3c.www.protocol.http.HttpServerState state,
                       java.lang.String host,
                       int port,
                       int timeout)
                throws HttpException

HttpServer implementation - Initialize this server to its target.

Specified by:

initialize in class HttpServer

Parameters:

manager - The central HTTP manager.

state - The manager's state for that server.

host - The target server's host name.

port - The target server's port number.

timeout - The timeout for the connection handled by the server

Throws:

HttpException - If the server host couldn't be resolved to one or more IP addresses.

initialize

public void initialize(HttpManager manager,
                       org.w3c.www.protocol.http.HttpServerState state,
                       java.lang.String host,
                       int port,
                       int timeout,
                       int conn_timeout)
                throws HttpException

HttpServer implementation - Initialize this server to its target.

Specified by:

initialize in class HttpServer

Parameters:

manager - The central HTTP manager.

state - The manager's state for that server.

host - The target server's host name.

port - The target server's port number.

timeout - The timeout for the connection handled by the server

timeout - The connection timeout in millisecond for the sockets

Throws:

HttpException - If the server host couldn't be resolved to one or more IP addresses.

notifyObserver

protected void notifyObserver(RequestObserver obs,
                              Request request,
                              int code)

notifyObserver

protected void notifyObserver(RequestObserver obs,
                              RequestEvent evt)

isTwoStage_10

protected boolean isTwoStage_10(Request request)

Is this request a two stage request.

Returns:

A boolean, true if the request is two stage, false otherwise.

isTwoStage_11

protected boolean isTwoStage_11(Request request)

Is this request a two stage request.

Returns:

A boolean, true if the request is two stage, false otherwise.

getRequestMode

protected int getRequestMode(Request request)

Get the current mode of running request for that server. This method check our knowledge of the target server, and deduce the mode in which the given request should be run.

Returns:

An integer code, indicating the mode in which the request should be run:

RQ_HTTP11

The request should be run as an HTTP/1.1 request.

RQ_HTTP10

The request should be run as an HTTP/1.0 request.

RQ_HTTP10_KA

HTTP/1.0 with keep-alive support.

RQ_UNKNOWN

This is the first request, we don't know yet.

http11_run

protected Reply http11_run(org.w3c.www.protocol.http.HttpBasicConnection conn,
                           Request request)
                    throws java.io.IOException,
                           MimeParserException

Run a fully HTTP/1.1 compliant request. This request has no body, so we can do whatever we want with it, and retry as many time as we want.

Parameters:

conn - The connection to run the request on.

request - The request to run.

Returns:

A Reply instance, if success; null if the request should be retried.

Throws:

java.io.IOException - If some IO error occured.

MimeParserException - If some MIME parsing error occured.

http11_ts_run

protected Reply http11_ts_run(org.w3c.www.protocol.http.HttpBasicConnection conn,
                              Request request)
                       throws java.io.IOException,
                              MimeParserException

Run a two stage HTTP/1.1 compliant request. The neat thing about this sort of request is that as they support 100 status codes, we know when we have to retry them.

Parameters:

conn - The connection to run the request on.

request - The request to run.

Returns:

A Reply instance, if success; null if the request should be retried.

Throws:

java.io.IOException - If some IO error occured.

MimeParserException - If some MIME parsing error occured.

http10_ka_run

protected Reply http10_ka_run(org.w3c.www.protocol.http.HttpBasicConnection conn,
                              Request request)
                       throws java.io.IOException,
                              MimeParserException

Run an HTTP/1.0 request that has support for keep alive. This kind of request are the worst one with regard to the retry strategy we can adopt.

Parameters:

conn - The connection to run the request on.

request - The request to run.

Returns:

A Reply instance, if success; null if the request should be retried.

Throws:

java.io.IOException - If some IO error occured.

MimeParserException - If some MIME parsing error occured.

http10_run

protected Reply http10_run(org.w3c.www.protocol.http.HttpBasicConnection conn,
                           Request request)
                    throws java.io.IOException,
                           MimeParserException

Run a simple HTTP/1.0 request. This server doesn't support keep-alive, we know the connection is always fresh, we don't need to go into the retry buisness.

That's cool !

Parameters:

conn - The connection to run the request on.

request - The request to run.

Returns:

A Reply instance, if success; null if the request should be retried.

Throws:

java.io.IOException - If some IO error occured.

MimeParserException - If some MIME parsing error occured.

http_unknown

protected Reply http_unknown(org.w3c.www.protocol.http.HttpBasicConnection conn,
                             Request request)
                      throws java.io.IOException,
                             MimeParserException

Run that request, we don't know what server we have at the other end. We know the connection is fresh, we use the http10_run and update the server infos by the end of processing.

Parameters:

conn - The connection to run the request on.

request - The request to run.

Returns:

A Reply instance, if success; null if the request should be retried.

Throws:

java.io.IOException - If some IO error occured.

MimeParserException - If some MIME parsing error occured.

doRequest

protected Reply doRequest(org.w3c.www.protocol.http.HttpBasicConnection conn,
                          Request request)
                   throws java.io.IOException,
                          MimeParserException

Exceute given request on given conection, according to server.

Parameters:

conn - The connection to use to run that request.

request - The request to execute.

Throws:

java.io.IOException - If some IO error occurs, or if the request is interrupted.

MimeParserException - If taregt server doesn't conform to the HTTP specification.

interruptRequest

protected void interruptRequest(Request request)

Interrupt given request, that was launched by ourself.

Specified by:

interruptRequest in class HttpServer

Parameters:

request - The request to interrupt.

runRequest

public Reply runRequest(Request request)
                 throws HttpException

Run the given request in synchronous mode.

Specified by:

runRequest in class HttpServer

Parameters:

request - The request to run.

Returns:

A Reply instance, containing the reply headers, and the optional reply entity, to be read by the calling thread.

Throws:

HttpException - If the request processing failed.