The TemplateFilter sends HTML content through an
Html/XML parser to a set of Templates. Each Html/XML tag may
dynamically invoke a Java method present in the Templates.
The dynamically-generated content from evaluating the Html/XML tags is
returned to the caller.
The following configuration parameters are used to initialize this
Filter.
templates
A list of Template class names whose methods will be
invoked by the XML tags present in the content.
session
The request property that contains the session ID. If no
"session" property is found with the supplied prefix, then
the global "session" property is used instead. The default
value is "SessionID".
The TemplateHandler class is similar, but not identical to
running a FilterHandler with the FileHandler and
the TemplateFilter. The differences between the two should
be resolved.
Note: The templates currently accepts only a list of
class names, and not tokens that could be used to represent
class named. This may be changed in the future. Until then, all
template classes share the TemplateHandler's properties prefix.
filter(Request request,
MimeHeaders headers,
byte[] content)
Evaluates the content as html/XML tags, if the file is (or has now been
converted to) "text/html".
respond(Request request)
No action before request is made
boolean
shouldFilter(Request request,
MimeHeaders headers)
Filters all HTML files, or files that are likely to be html files,
specifically, those whose "Content-Type" starts with "text/".
server - The HTTP server that created this Handler.
Typical Handlers will use Server.props
to obtain run-time configuration information.
prefix - A prefix that this Handler may prepend to all
of the keys that it uses to extract configuration information
from Server.props. This is set (by the Server
and ChainHandler) to help avoid configuration parameter
namespace collisions.
For example, if a Handler uses the property
"account", and the specified prefix is "bank.", then the
Handler should actually examine the property
"bank.account" in Server.props.
Returns:
true if this Handler initialized
successfully, false otherwise. If
false is returned, this Handler
should not be used.
request - The Request object that represents the HTTP
request.
Returns:
true if the request was handled. A request was
handled if a response was supplied to the client, typically
by calling Request.sendResponse() or
Request.sendError.
Throws:
IOException - if there was an I/O error while sending the response to
the client. Typically, in that case, the Server
will (try to) send an error message to the client and then
close the client's connection.
The IOException should not be used to silently
ignore problems such as being unable to access some
server-side resource (for example getting a
FileNotFoundException due to not being able
to open a file). In that case, the Handler's
duty is to turn that IOException into a
HTTP response indicating, in this case, that a file could
not be found.
headers - The MIME headers generated by the Handler.
content - The output from the Handler that this
Filter may rewrite.
Returns:
The rewritten content. The Filter may return
the original content unchanged. The
Filter may return null to indicate
that the FilterHandler should stop processing the
request and should not return any content to the client.
