<![CDATA[
/*
* @(#)AutoRun.java (Metawerx customer example classes)
*
* Copyright (c) 1998-2005 Metawerx. All Rights Reserved.
*
* This software is the confidential and proprietary information of Metawerx
* ("Confidential Information"). You shall not disclose such Confidential
* Information and shall use it only in accordance with the terms of the
* license agreement you entered into with Metawerx.
*
* METAWERX MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY
* OF THE SOFTWARE OR THE SOURCE CODE, EITHER EXPRESS OR IMPLIED, INCLUDING
* BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
* A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. METAWERX SHALL NOT BE LIABLE
* FOR ANY DAMAGES SUFFERED BY ANY PARTY AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE AND DOCUMENTATION OR ITS DERIVATIVES
*
*
* Synopsis
* =====================================================================================
* This code demonstrates an AutoRun servlet using the <load-on-startup> tag
*
* Initialisation code is placed into the runInitialisation() routine.
*
* The following code is placed into web.xml to run this servlet when the webapp
* is started.
<servlet>
<servlet-name>AutoRun</servlet-name>
<servlet-class>AutoRun</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>AutoRun</servlet-name>
<url-pattern>/autorunme</url-pattern>
</servlet-mapping>
* If this is the ROOT web-app...
* the servlet can also be started by going to URL http://site/autorunme
*
* If this is not the ROOT web-app...
* the servlet can also be started by going to URL http://site/appName/autorunme
*
*
* Complete file structure for Tomcat for this sample
* =====================================================================================
JAKARTA-WEBAPPS
JAKARTA-WEBAPPS/AutoSample
JAKARTA-WEBAPPS/AutoSample/WEB-INF
JAKARTA-WEBAPPS/AutoSample/WEB-INF/web.xml
JAKARTA-WEBAPPS/AutoSample/WEB-INF/classes/AutoRun.class
*
* Complete, minimal web.xml file for this sample
* =====================================================================================
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<display-name>Metawerx Samples</display-name>
<description>Metawerx Samples</description>
<servlet>
<servlet-name>AutoRun</servlet-name>
<servlet-class>AutoRun</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>AutoRun</servlet-name>
<url-pattern>/autorunme</url-pattern>
</servlet-mapping>
</web-app>
* History
* =====================================================================================
* 9/17/2005 17:13 Neale Rudd
* Added more documentation
* 7/22/2005 08:42 Neale Rudd
* Added web.xml example and file tree layout
* 7/17/2005 22:23 Neale Rudd
* Created
*
*/
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class AutoRun extends HttpServlet {
// Flag to indicate whether we initialised or not
protected static boolean initialisedOk = false;
// Dummy object just used for synchronization in the example,
// to ensure only one thread executes the initialization.
private static Object thisClassSync = new Object();
// This function is run when the servlet is initialised
// Therefore, it will get run by the servlet-container when the application starts
// because of the load-on-startup tag in web.xml
public void init(ServletConfig config) {
// Run initialiser, get response as string
String message = runInitialisation();
// Output to System.out for debugging
System.out.println("[AutoRun]: "+message);
}
// This function is only run when accessed by the browser (user-agent)
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
// Only run this once at a time
synchronized (thisClassSync) {
if(!initialisedOk) {
// Run initialiser, get response as string
String message = runInitialisation();
// Output response to browser
PrintWriter out = new PrintWriter(response.getOutputStream());
out.println(message);
out.close();
} else {
// Output to System.out for debugging
// Note that System.out.println() in a synchronised block will cancel the synchronisation
// because of operating system I/O, therefore only uncomment this line during debugging.
System.out.println("[AutoRun]: Already initialised");
// Already initialised
PrintWriter out = new PrintWriter(response.getOutputStream());
out.println("Already initialised");
out.close();
}
}
}
// Perform work in here
private String runInitialisation() {
// ...
// Do something here on startup, such as initialising data structures, or obtaining
// data from a remote server.
// ...
// Set flag to tell if we are initialised on subsequent calls
initialisedOk = true;
// Return something which can be used either by init() or by doGet()
return("Ok - initialised");
}
}
]]>