org.apache.jserv
Class JServ

java.lang.Object
  |
  +--javax.servlet.GenericServlet
        |
        +--javax.servlet.http.HttpServlet
              |
              +--org.apache.jserv.JServ

public class JServ

extends javax.servlet.http.HttpServlet

implements JServLogChannels, JServDefs

JServ is the entry point to the Java part of JServ

It sets up the server, initalizes everything, and listens on a TCP port for requests for the server. When it gets a request, it launches a JServConnection thread.

Version:

$Revision: 1.58 $ $Date: 2000/03/31 16:05:04 $

See Also:

Serialized Form

Field Summary

static java.lang.String[]	colors
(package private) static java.lang.String	confFile
protected static Configurations	confs
static java.lang.String	DEFAULT_CONTROLLER
static int	DEFAULT_PORT Default port to listen to.
private static java.net.ServerSocket	listenSocket
protected static JServLog	log
protected static WorkerPool	pool
private static Semaphore	semaphore
protected static java.util.Hashtable	servletManagerTable
private static java.lang.String	SINGLE_COLUMN
private static java.lang.String	STATUS_SERVLET
private static java.util.Hashtable	table

Fields inherited from class javax.servlet.GenericServlet

config

Constructor Summary

JServ()

Method Summary

private static java.net.InetAddress	bindTo(java.lang.String HostName) returns the InetAddress this JServ is binding to read from properties file.
protected static void	clear() Clears JServ and prepare it for restart of termination
protected static void	fail(java.lang.String msg) Exit with an error message.
protected static void	fail(java.lang.String msg, java.lang.Throwable e) Exit with an error message formatted using the exception message.
private void	handleStatus(javax.servlet.ServletOutputStream out, java.lang.String query)
private void	handleZones(javax.servlet.ServletOutputStream out, java.lang.String query)
static void	main(java.lang.String[] argument) Start up JServ.
protected static void	restart() Restart JServ.
private void	sendHead(javax.servlet.ServletOutputStream out)
private void	sendTail(javax.servlet.ServletOutputStream out)
void	service(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res) JServ is also a servlet that returns info to the client about its status.
private void	showMenu(javax.servlet.ServletOutputStream out)
private static void	signal(java.lang.String signal) Signal a running JServ.
(package private) static void	start() Read the host configuration property file and perform all the specified actions.
protected static void	terminate() Terminate JServ.
private static void	usage() Prints the help on usage message on standard error.
static java.lang.String	version()
private static void	welcome() Prints the welcome message on standard output.
private void	writeTable(javax.servlet.ServletOutputStream out, java.lang.String name, java.util.Hashtable table, java.lang.String[] rowColors)

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getAllDeclaredMethods, getLastModified, maybeSetLastModified, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, init, log

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PORT

public static final int DEFAULT_PORT

Default port to listen to. There are two cases when this value is engaged:

• No port parameter is specified in the jserv.properties
• Value specified is outside the valid range (1024-65535). The lower one is the minimum allowed for non-root listening socket, the upper one is imposed by the operating system limitations. The latter restriction may be lifted in the future (there are UNIX flavors which already don't have it).

Initialized in init.

DEFAULT_CONTROLLER

public static final java.lang.String DEFAULT_CONTROLLER

colors

public static final java.lang.String[] colors

servletManagerTable

protected static java.util.Hashtable servletManagerTable

confs

protected static Configurations confs

log

protected static JServLog log

pool

protected static WorkerPool pool

listenSocket

private static java.net.ServerSocket listenSocket

table

private static java.util.Hashtable table

semaphore

private static Semaphore semaphore

confFile

static java.lang.String confFile

SINGLE_COLUMN

private static final java.lang.String SINGLE_COLUMN

STATUS_SERVLET

private static final java.lang.String STATUS_SERVLET

Constructor Detail

JServ

public JServ()

Method Detail

version

public static final java.lang.String version()

main

public static void main(java.lang.String[] argument)

Start up JServ.

The command line usage is the following:

java org.apache.jserv.JServ configFile

where configurationFile if JServ configuration file.

Parameters:

arguments - Command line parsed into strings.

welcome

private static void welcome()

Prints the welcome message on standard output. This is seen only from manual operation. This method is called from main.

usage

private static void usage()

Prints the help on usage message on standard error. This method is called from main.

start

static void start()

Read the host configuration property file and perform all the specified actions. This method is called from main.

clear

protected static void clear()

Clears JServ and prepare it for restart of termination

bindTo

private static java.net.InetAddress bindTo(java.lang.String HostName)

returns the InetAddress this JServ is binding to read from properties file.

restart

protected static void restart()

Restart JServ. Note: due to a bug in the JavaSoft JVM on some platforms (win32), closing a server socket and rebinding to the same port produces a chain of hidden exception being thrown when the accept() method is created.

The JVM tries to bind on the port and starts an hidden loop that consumes all the CPU and makes JServ appear burried in an infinite loop. This doesn't prevent JServ to restart gracefully, but it suddently appears dead from a network point of view and consumes all the CPU resources

Unfortunately, there is nothing we can do but wait for JVM implementors to fix this nasty bug. :-( (SM)

terminate

protected static void terminate()

Terminate JServ.

signal

private static void signal(java.lang.String signal)

Signal a running JServ.

fail

protected static void fail(java.lang.String msg,
                           java.lang.Throwable e)

Exit with an error message formatted using the exception message.

fail

protected static void fail(java.lang.String msg)

Exit with an error message.

service

public void service(javax.servlet.http.HttpServletRequest req,
                    javax.servlet.http.HttpServletResponse res)
             throws javax.servlet.ServletException,
                    java.io.IOException

JServ is also a servlet that returns info to the client about its status. Security checks are performed by the Apache side but we have the chance to disable this behavior from this side, too.

This servlet is used as installation and configuration feedback, since its correct functioning tells the user JServ is correctly working. Since this class will always be in the executing JVM's classpath, the user receive this output if Apache and JServ are setup correctly, forgetting about the servletzone configurations that may be done later on.

Throws:

javax.servlet.ServletException - when servlet request fails

Overrides:

service in class javax.servlet.http.HttpServlet

sendHead

private void sendHead(javax.servlet.ServletOutputStream out)
               throws java.io.IOException

sendTail

private void sendTail(javax.servlet.ServletOutputStream out)
               throws java.io.IOException

showMenu

private void showMenu(javax.servlet.ServletOutputStream out)
               throws java.io.IOException

handleStatus

private void handleStatus(javax.servlet.ServletOutputStream out,
                          java.lang.String query)
                   throws java.io.IOException

handleZones

private void handleZones(javax.servlet.ServletOutputStream out,
                         java.lang.String query)
                  throws java.io.IOException

writeTable

private void writeTable(javax.servlet.ServletOutputStream out,
                        java.lang.String name,
                        java.util.Hashtable table,
                        java.lang.String[] rowColors)
                 throws java.io.IOException