Chapter 23 Creating Java Servlets

Server properties for servlets

On the Servlet tab in the Server Properties window, you can disable servlet execution in a Jaguar server and configure additional properties to control the execution of servlets.

Displaying the Servlet tab

To display the Servlet execution properties:

Highlight the icon for the server of interest.
Choose File | Server Properties.
Scroll the tab display at the top of the window until the Servlet tab displays, then click on it.

Servlet tab controls

The Servlet tab specifies how Jaguar executes servlets, as follows:

Servlet Execution Enable/Disable This option determines whether servlets can execute on a server. If the option is disabled, no installed servlets can be invoked. By default, servlet execution is enabled.
Allow Servlet Invocation by Class Name If this option is enabled, users can invoke a servlet by typing the name of its Java class rather than a Jaguar Manager servlet name. For example:
```
http://yourhost:8080/servlet/com.yours.AServlet
```
By default, invocation by class name is allowed. You may wish to disable such access for the following reasons:
- Disabling the option restricts available servlets to those that have been installed in the server's Servlets folder in Jaguar Manager.
- When Servlets are invoked by class name, they are run according to the default servlet property settings. These settings may not be appropriate for some servlets.
Servlet Aliases Specifies the list of path prefixes that users can use to invoke servlets from HTTP URLs. For example, if /servlet/ is a path prefix, this URL invokes a servlet named MyServlet:
```
http://yourhost:8080/servlet/MyServlet
```
The default setting specifies /servlet/ as the only path prefix. To override the default, enter one or more prefixes, each on a line by itself. For example:
```
/servlet/
/servlets/
```
Servlet Timeout This option specifies how long the Jaguar server should wait for each servlet's init method to return. The timeout period is measured in seconds. The default is 0, which indicates that there is no time limit.
You can override the server-wide default timeout for individual servlets. Display the All Properties tab in the Servlet Properties window, then set the com.sybase.jaguar.servlet.init.timeout property to the desired number of seconds.

If a servlet's init method might run indefinitely, specify a finite timeout period. If the init method does not return in the specified timeout period, the server abandons the servlet and it will be unavailable until the server is restarted or refreshed. Service requests that arrive while init is running are blocked until init returns. If init is allowed to run indefinitely, clients will receive browser timeout errors when attempting to execute the servlet.
Destroy Timeout Jaguar calls each servlet's destroy method before shutting down or after you have refreshed or stopped the servlet using Jaguar Manager. If service calls are still active, this setting specifies the number of seconds that the server should wait for the service calls to return before calling the destroy method. The default is 0, which specifies that Jaguar calls destroy immediately.
You can override the server-wide default wait-time for individual servlets. Display the All Properties tab in the Servlet Properties window, then set the com.sybase.jaguar.servlet.destroy.wait-time property to the desired number of seconds.