Sunday, April 21, 2002 11:41 PM
1. servlets are well established technology, so using them would be easier than implementing a listening server on a raw socket. Look for a good (free) servlet container like tomcat or jetty.
2. database is the best solution. Cloudscape, pure java, serving JDBC, ships freely with J2EE. However:
3. "triggers" are what you are looking for. They automatically "fire" when a database table you have specified is updated. Triggers are part of a professional database like Oracle...i don't know if Cloudscape has them. Not using triggers would pose the problems you stated.
Think of how the database is updated. Maybe the best thing would be to create a single program that does all the database updates. When a news object enters the application it could first enter it into the database and then scan for all the users subscribed to the category (eg sport) and email/SMS them. This way they're sure to get new news.