public int getCacheSize() {
        return cacheSize;
    }
A single method that must create a new instance of the cache.
The returned instance MUST implement at least the {@link Map#get} and {@link Map#put}
methods in a threadsafe way if you intend to use this in a multithreaded scenario.
Yauaa only uses the put and get methods and in exceptional cases the clear method.
An implementation that does some kind of automatic cleaning of obsolete values is recommended (like LRU).
@param cacheSize is the size of the new cache (which will be >= 1)
@return Instance of the new cache.
analyzer/src/main/java/nl/basjes/parse/useragent/AbstractUserAgentAnalyzer.java