[MYFACES-3130] [perf] Avoid unnecessary AbstractList$Itr instances

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.3.0
• Component/s: JSR-314
• Environment: myfaces core trunk
• Assignee: Thomas Andraschko
• Reporter: Martin Kočí
• Created: 06/May/11 17:41
• Updated: 02/Sep/18 10:10
• Resolved: 14/Aug/17 13:42

Description

Similar issue: MYFACES-3129

loop from java 5:

for (Object object: objects)

creates new instance of AbstractList$Itr, if objects are instance of ArrayList.

Similar situation is with explicit .iterator() call.

In my testcases, it is about ~ 100 000 instances per request/response. Creation itself is cheap, but triggers GC lately.

I suggest to use old index-style for (i = 0; i < childCount; i++) if possible. Are there any rawbacks of index-based iteration?
Children is List and as implementation detail we know that it is instance of ArrayList.

Sub-Tasks

• [perf] reduce (internal) usage of getFacetsAndChildren(): Closed
• [PERF] Use index-based loop where possible: Closed
• [PERF] Use index-based loop where possible - part II: Closed