Request Dispatcher 
Use
This is the entry point of the PRT. In the SAP J2EE Engine environment, it is implemented as a servlet running in the Web server environment.
The first role of the request dispatcher is to match the URL of the request to a portal connection and forwards the request to this portal connection.
The dispatcher can handle all the required connections. However, the PRT must have at least the default servlet connection named portal installed and started if it is to work properly.
Features
When a request comes in, the dispatcher analyses the incoming URL and finds the corresponding connection to forward the message. The name of the connection is passed in the URL as /irj/servlet/prt/<ConnectionName>.
The name is used as key to perform a lookup in the connection bound of the portal registry.
The dispatcher contains a set of APIs that could be accessed from an external servlet to communicate with the dispatcher. Those libraries are packaged in the WEB-INF/lib directory:
Library |
Description |
prtdispatcher.jar |
The code of the dispatcher |
prtjndisupport.jar |
JDNI support in PRT |
prtregistry.jar |
API of the portal registry |
prtutil.jar |
Utility classes of the portal runtime |
Activities
At startup, the role of the request dispatcher is to:
· Initialize the PRT environment. The request dispatcher reads the following configuration files from the WEB-INF/conf/dispatcher.properties installation file
Property |
Default Value |
Description |
dispatcher.contactinfo |
Default information message displayed when a dispatcher exception occurs |
The reason for the exception is always displayed before or in the source code of the HTML page |
dispatcher.servlet.allow |
true |
Defines whether automatic forward to another servlet is permitted |
dispatcher.servlet.prefix |
Servlet |
Allows the pathinfo prefix to be used |
dispatcher.portal.root |
WEB-INF/portal |
The portal root directory |
dispatcher.portal. systemdefault.properties |
system/properties/prtDefault.properties |
The portal default properties |
dispatcher.portal.system.properties |
system/properties/workplace.properties |
The portal properties |
dispatcher.portal.defaultconnection |
Portal |
The default connection |
dispatcher.log.console |
Verbose |
Console mode for the dispatcher |
dispatcher.version |
|
Automatically generated version information |
· Set up the class loader hierarchy. The different levels of libraries are read from the installation file and the corresponding class loaders are created in the memory. This phase can also be customized with the following parameters of the prtDefault.properties file:
Property Name |
Default Value |
Description |
portal.libs |
lib |
The directory below WEB-INF/portal containing the public library of the PRT |
portal.classes |
classes |
Same for the public classes |
system/lib |
system/lib |
The directory below WEB-INF/portal containing the non-public library of the PRT |
system/classes |
system/classes |
The directory below WEB-INF/portal containing the non-public classes |
portal.protected.classes |
com.sun.xml., javax.mail.,com.sun.mail., javax.activation |
Prefixes for class names that are not seen from the dispatcher and below |
portal.protected.resources |
localization, META-INF |
Prefixes for resources names that are not seen from the dispatcher and below |