Optimize workaround for UTF-8 encoding in servlet-filters inside liferay-hooks

[stampedev]

hook_securefilter contains a servlet-filter to restrict access to certain URLs that should not be available, if not properly registered as liferay user. However, such servlet-filters break UTF-8 encoding (e.g. of HTTP parameters) if not chained with an encoding-filter inside the hook itself.

It is currently unclear why this happens, because liferay itself contains this filter on container-level (i.e. in Tomcat) and not inside Liferay (i.e. application web.xml). Simply addressing this issue by defining an element in the liferay-hook.xml, referencing the global filter does not work.
This however, is currently fixed, by adding the encoding filter a second time, which is neither efficient and may even lead to other side effects.

Therefore we need some research on how filters are addressed and chained in Liferay and how to optimize our current hook to prevent breaking the encoding without an additional filter.