How can I have a class run on start-up?
Hi, hopefully someone can help me with this. I need some type of a class to start when the web server starts. This class is going to bind itself to a port and listen to commands from a VB app. Other classes in other web apps will register themselves with this class to receive these commands. My questions are: 1: how can you have a class start when the web server starts? This needs to work with all web servers. 2: how can you have a class in a web app register itself with the class listening on the port? Any suggestions are appreciated. Regards Alex Colic
Re: How can I have a class run on start-up?
I don't know the answer to your question, but, I'm wondering if the application actually has to run in Tomcat. It sounds like you might want to just create a standalone application that listens on a port. Jon - Original Message - From: Alex Colic [EMAIL PROTECTED] To: Tomcat-User [EMAIL PROTECTED] Sent: Friday, September 07, 2001 8:36 AM Subject: How can I have a class run on start-up? Hi, hopefully someone can help me with this. I need some type of a class to start when the web server starts. This class is going to bind itself to a port and listen to commands from a VB app. Other classes in other web apps will register themselves with this class to receive these commands. My questions are: 1: how can you have a class start when the web server starts? This needs to work with all web servers. 2: how can you have a class in a web app register itself with the class listening on the port? Any suggestions are appreciated. Regards Alex Colic
RE: How can I have a class run on start-up?
you could implement a org.apache.catalina.LifecycleListener and attach it to the context you are using like this: Context path=/myapp ... ... Listener className=com.mycompany.MyAppListener/ ... /Context look into the docs for details. but this is a tomcat-specific thing (and thus not portable). anyway there's a second approach that comes in mind (but it is not as clean as the first one) you simply could write a servlet where you put all code which should be executed during webapp-initialization into the init-method. in web.xml you configure the servlet to load on startup. it goes like this: servlet servlet-namesomename/servlet-name servlet-classsomeclass/servlet-class load-on-startupa value greater 0/load-on-startup /servlet then the servlet will be called upon webapp-initialization. dont know if there's is a better (cleaner and portable) solution, but these two do the job. greets, pero -Original Message- From: Jonathan Eric Miller [mailto:[EMAIL PROTECTED]] Sent: Friday, September 07, 2001 7:15 PM To: [EMAIL PROTECTED] Subject: Re: How can I have a class run on start-up? I don't know the answer to your question, but, I'm wondering if the application actually has to run in Tomcat. It sounds like you might want to just create a standalone application that listens on a port. Jon - Original Message - From: Alex Colic [EMAIL PROTECTED] To: Tomcat-User [EMAIL PROTECTED] Sent: Friday, September 07, 2001 8:36 AM Subject: How can I have a class run on start-up? Hi, hopefully someone can help me with this. I need some type of a class to start when the web server starts. This class is going to bind itself to a port and listen to commands from a VB app. Other classes in other web apps will register themselves with this class to receive these commands. My questions are: 1: how can you have a class start when the web server starts? This needs to work with all web servers. 2: how can you have a class in a web app register itself with the class listening on the port? Any suggestions are appreciated. Regards Alex Colic
Re: How can I have a class run on start-up?
Hmm. I don't know about that. For the user that would just be another app he has to start. I was trying to automate things. I was wondering about creating a servlet and forcing it to run when Tomcat starts. What do you thing? Alex - I don't know the answer to your question, but, I'm wondering if the application actually has to run in Tomcat. It sounds like you might want to just create a standalone application that listens on a port. Jon
RE: How can I have a class run on start-up?
For a portable solution to the run my class at startup problem, Servlet 2.3 (and therefore Tomcat 4.0) supports a new API called javax.servlet.ServletContextListener. If you register such a listener in your web.xml file, the container will call the contextInitialized() method when the web application starts up, and contextDestroyed() when the web application is shut down. This is safer than the typical approach (use the init() method of a load-on-startup servlet), because the servlet specification does *not* guarantee to keep any particular servlet instance in memory for the life of the application (although Tomcat actually does so). Craig On Fri, 7 Sep 2001, Peter Romianowski wrote: Date: Fri, 7 Sep 2001 19:35:32 +0200 From: Peter Romianowski [EMAIL PROTECTED] Reply-To: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: RE: How can I have a class run on start-up? you could implement a org.apache.catalina.LifecycleListener and attach it to the context you are using like this: Context path=/myapp ... ... Listener className=com.mycompany.MyAppListener/ ... /Context look into the docs for details. but this is a tomcat-specific thing (and thus not portable). anyway there's a second approach that comes in mind (but it is not as clean as the first one) you simply could write a servlet where you put all code which should be executed during webapp-initialization into the init-method. in web.xml you configure the servlet to load on startup. it goes like this: servlet servlet-namesomename/servlet-name servlet-classsomeclass/servlet-class load-on-startupa value greater 0/load-on-startup /servlet then the servlet will be called upon webapp-initialization. dont know if there's is a better (cleaner and portable) solution, but these two do the job. greets, pero -Original Message- From: Jonathan Eric Miller [mailto:[EMAIL PROTECTED]] Sent: Friday, September 07, 2001 7:15 PM To: [EMAIL PROTECTED] Subject: Re: How can I have a class run on start-up? I don't know the answer to your question, but, I'm wondering if the application actually has to run in Tomcat. It sounds like you might want to just create a standalone application that listens on a port. Jon - Original Message - From: Alex Colic [EMAIL PROTECTED] To: Tomcat-User [EMAIL PROTECTED] Sent: Friday, September 07, 2001 8:36 AM Subject: How can I have a class run on start-up? Hi, hopefully someone can help me with this. I need some type of a class to start when the web server starts. This class is going to bind itself to a port and listen to commands from a VB app. Other classes in other web apps will register themselves with this class to receive these commands. My questions are: 1: how can you have a class start when the web server starts? This needs to work with all web servers. 2: how can you have a class in a web app register itself with the class listening on the port? Any suggestions are appreciated. Regards Alex Colic
