[FLEX-34765] ArrayCollection/ListCollectionView performance improvements

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: Apache Flex 4.14.0
• Component/s: Collections
• Labels: easyfix newbie performance
• Assignee: Unassigned
• Reporter: shane doolan
• Created: 25/Feb/15 00:30
• Updated: 08/Nov/16 00:41

Description

ListCollectionView immediatly adds a CollectionEvent listener to its source list, even though it only needs the events if sort is set, filterFunction is set, or it has a CollectionEvent listener of its own.

ArrayList suppresses CollectionEvent creation if there is no CollectionEvent listener, so by only adding the listener when needed we can improve performance while reducing the number of CollectionEvent/Array allocations.

Performance profiling of the patch:

label	type	objectCount	addItemAtStart	addItemAtEnd	addItemAtRandom	removeItemAtStart	removeItemAtEnd	removeItemAtRandom
Original ArrayCollection: original ArrayList	class ArrayCollection	100000	2538.556ms	2575.138ms	3268.842ms	3095.744ms	2555.533ms	2828.339ms
Patched ArrayCollection: original ArrayList	class ArrayCollectionListenerPatch	100000	2339.321ms	2338.553ms	3080.970ms	2927.168ms	2364.032ms	2706.899ms
Patched ArrayCollection: original ArrayList + CollectionEvent listener	class ArrayCollectionListenerPatch	100000	2561.900ms	2521.983ms	3262.963ms	3149.099ms	2533.680ms	2884.201ms

Performance profiling of the patch with the patched ArrayList from FLEX-34759:

label	type	objectCount	addItemAtStart	addItemAtEnd	addItemAtRandom	removeItemAtStart	removeItemAtEnd	removeItemAtRandom
Original ArrayCollection: patched ArrayList	class ArrayCollection	100000	240.839ms	273.501ms	3296.476ms	926.919ms	208.949ms	2856.562ms
Patched ArrayCollection: patched ArrayList	class ArrayCollectionListenerPatch	100000	62.039ms	65.500ms	3131.238ms	706.865ms	36.314ms	2676.732ms
Patched ArrayCollection: patched ArrayList + CollectionEvent listener	class ArrayCollectionListenerPatch	100000	298.581ms	243.448ms	3282.985ms	935.452ms	228.865ms	2880.552ms

In the above examples: when the patched ArrayCollection doesn't have a CollectionEvent listener, sort, or filter we avoid allocation of 200,000 unused CollectionEvents (2 for each add/remove - one dispatched by the array list to the ListCollectionView, one cloned by the ListCollectionView and dispatched to nobody)

Issue Links

• is related to: FLEX-34759 ArrayList/ArrayCollection performance improvements