On Tue, 25 Feb 2020 00:45:06 GMT, Kevin Rushforth <k...@openjdk.org> wrote:
>> modules/javafx.base/src/main/java/com/sun/javafx/binding/ExpressionHelper.java >> line 194: >> >>> 193: private Map<InvalidationListener, Integer> >>> invalidationListeners = new LinkedHashMap<>(); >>> 194: private Map<ChangeListener<? super T>, Integer> >>> changeListeners = new LinkedHashMap<>(); >>> 195: private T currentValue; >> >> Two comments on this: >> >> 1. The old implementation initialized these lazily, so we might want to >> preserve that behavior. I think it is reasonable since in most cases an >> observable won't have both types of listeners attached to it. >> 2. Since we're dealing wither performance optimizations here, we should >> think about what the `initialCapcity` and `loadFactor` of these maps should >> be, as it can greatly increase performance when dealing with a large amount >> of entries. > > Adding to this, we need to ensure that the simple case of a few listeners > doesn't suffer memory bloat. It may make sense to initially allocate a Map > with a small capacity and load factor, and then reallocate it if someone adds > more than a certain number of listeners. Agree with the lazy initialisation and the initial setting of capacity and load factor to reduce memory footprint unless it's needed. ------------- PR: https://git.openjdk.java.net/jfx/pull/108
