Sun Java System Portal Server 7.1 Technical Reference

Stages in the Filter Process

Both enumerator and generator filters have five phases in the filtering process. They both have four common phases: Setup, Metadata, Data, and Shutdown. If the resource makes it past the Data phase, it is either in the Enumerate or Generate phase, depending on whether the filter is an enumerator or a generator.

The phases are as follows:


Performs initialization operations. Occurs only once in the life of the robot.


Filters the resource based on metadata that is available about the resource. Metadata filtering occurs once per resource before the resource is retrieved over the network. The table below lists the common metadata types and their description.

Table 43–1 Common Metadata Types




Complete URL 

The location of a resource 


The access portion of the URL 

http, ftp, file 


The address portion of the URL 

IP address 

Numeric version of the host 


The path portion of the URL 



Number of links from the seed URL 


Filters the resource based on its data. Data filtering is done once per resource after it is retrieved over the network. Data that can be used for filtering include:

Enumerates the current resource in order to determine if it points to other resources to be examined.


Generates a resource description (RD) for the resource and saves it in the Search Engine database.


Performs any needed termination operations. Occurs once in the life of the robot.