Advanced Filtering Techniques

Summary

In this chapter, we’ve worked through five complete filter examples covering these application domains:

• Auditing

• Authorization

• Adapting legacy resources

• Authentication

• Request-processing pipeline

Working through the code to these filters, we’ve discussed the following:

• Generating our own response and blocking downstream processing

• Wrapping a response to transform or replace its content

• Wrapping a response to change its headers

• Wrapping a request to modify headers

• Accessing initialization parameters

• Dynamically altering filter behavior based on the incoming request

• Controlling the interaction of filters and the request dispatcher

• Applying filters in a processing pipeline configuration

You now have five examples that you can use as the basis for your own filter implementation. You also have one versatile class, ReplaceContentOutputStream, that you can use whenever you need to wrap a response to modify its content.

You should now be fluent in filtering technology, and you should be able to apply filters to many challenges that the real world may throw at you.