implement cleanup of expired resources in Java?

[dominik-cnx]

We currently comment all return statements from del.lua using

values.put("delscript", readLuaScriptFromClasspath(LuaScript.DELETE).replaceAll("return", "--return"));

and then inline the modified script into cleanup.lua

for key,value in pairs(resourcesToClean) do
redis.log(redis.LOG_NOTICE, "cleanup resource: "..value)
KEYS[1] = string.sub(value, resourcePrefixLength+1, string.len(value))

--%(delscript) <-- del.lua with commented return statements

counter = counter + 1
end

There are several disadvantages with this approach:

a) We can't use functions such as

local function isResource(key)
return redis.call('exists',resourcesPrefix..key) <-- will be commented
end

in del.lua

b) We can't do a "return early from method"

c) We also increment the counter when nothing has been deleted

Hence the idea to get rid of the cleanup.lua and implement this in Java (but still call the del.lua).