Somedays you come across some code and think that’s pretty, why didn’t I think of that? So my long time colleague Mark Warner has a nice twist on the standard name/value store pattern using method references to deal with converting from a String.

int size = store.getProperty("cache.limit", 500, Integer::parseInt);
 boolean enabled = store.getProperty("cache.enabled", true, Boolean::getBoolean);

I took his example and refactored it slightly to return Optional, and I ended up with the following:

public Optional<String> getProperty(
 String propertyName) {
 return Optional.ofNullable(map.get(propertyName));
}
 
public <T> Optional<T> getProperty(
 String propertyName, 
 ThrowingFunction<String,? extends T,? extends Exception> func ) {

 return getProperty(propertyName).map(val -> {
 try {
 return func.apply( val );
 } catch ( Exception e ) {
 LOGGER.severe( () -> "Invalid property transform, will default " + e.getMessage() );
 return null;
 }
 });
}

This means that the default value ends up being provided by the Optional which is a nice application of OAOO.

int size = store.getProperty("cache.limit", Integer::parseInt).orElse(500);
 boolean enabled = store.getProperty("cache.enabled", Boolean::getBoolean).orElse(true);

I think this is even tidier; but it does depend on who you feel about using Optionals.