Statistics of parsing and cache usage

[alexabreuplanet]

Is there a way to access statistics on the number of executed parsings and cache usage — including how many entries were used and how many parses were avoided due to cache hits?

[nielsbasjes]

The default implementation does not expose this.
The solution is quite simple because you can easily override the caching implementation (so you can take full control).

NOTE: The caching for the useragents and for the clienthints is separate, so you'll have 2 of these!

Create new classes similar this

yauaa/analyzer/src/main/java/nl/basjes/parse/useragent/cache/Java11CacheInstantiator.java

Lines 25 to 29 in 6e97063

	public class Java11CacheInstantiator implements CacheInstantiator {
	@Override
	public Map<String, UserAgent.ImmutableUserAgent> instantiateCache(int cacheSize) {
	return Caffeine.newBuilder().maximumSize(cacheSize).<String, UserAgent.ImmutableUserAgent>build().asMap();
	}

and this

yauaa/analyzer/src/main/java/nl/basjes/parse/useragent/cache/Java11ClientHintsCacheInstantiator.java

Lines 25 to 28 in 6e97063

	public class Java11ClientHintsCacheInstantiator<T extends Serializable> implements ClientHintsCacheInstantiator<T> {
	public Map<String, T> instantiateCache(int cacheSize) {
	return Caffeine.newBuilder().maximumSize(cacheSize).<String, T>build().asMap();
	}

Instead of immediately returning the instance you can keep a reference to the instance and expose the statistics you need.

This also allows you to choose any caching implementation you like.