Generator
A generator is a server-side component written in Java which produces an XML response from a content request. Berlioz libraries provide a number of built-in generators for common use cases.
It must follow the ContentGenerator Java interface.
public interface ContentGenerator {
void process(ContentRequest req, XMLWriter xml)
throws BerliozException, IOException;
}
Generators can have other features, for example, cacheable.
Usage
In order for a generator to be invoked, it must be part of a service. The same generator can be used in multiple services.
In the context of a service, a generator can be given a name and a target to make it easier for XSLT templates to match.
For example:
<service id="get-user" method="get">
<url pattern="/user/{username}"/>
<generator name="user" target="main" class="org.example.GetUser"/>
</service>
Examples
Generators can be used to return any content.
The following examples are only used to demonstrate how to write simple generators; they aren’t meant to be used verbatim in a production environment where other aspects such as caching and error handling should be considered.
Current user
A generator could return the user currently in the session. This kind of generator would be included in most services in the app.
public void process(ContentRequest req, XMLWriter xml) throws IOException {
HttpSession session = req.getSession();
User user = (user)session.getAttribute("org.example.User");
if (user != null) {
user.toXML(xml);
}
}
PSML document
A generator could also be used to return an XML or PSML document on the server.
public void process(ContentRequest req, XMLWriter xml) throws IOException {
String path = req.getBerliozPath();
File file = new File(PSML_ROOT, path+".psml");
if (file.exists()) {
XMLCopy.copyTo(file, xml);
}
}