[GROOVY-1915] Should use Integer.valueOf() instead of new Integer(), where appropriate

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.6-rc-1
• Component/s: class generator, parser, parser-antlr2
• Environment: I have tested it only under Groovy 1.0, not under the upcoming 1.1; But I guess it hasn't been fixed as this is the first time to come up in the discussions.
• Assignee: Paul King
• Reporter: Barzilai Spinak
• Created: 24/May/07 16:00
• Updated: 24/Nov/08 23:54
• Resolved: 16/Oct/08 12:58

Description

This stems from a discussion in the list : http://www.nabble.com/forum/ViewPost.jtp?post=10789037&framed=y
In that particular code, a Groovy expression such as:

if (x <= 0)

is translated into the Java equivalent of:

if(ScriptBytecodeAdapter.compareLessThanEqual(x, new Integer(0)))

This occurs in several other similar cases in that script's translation, and I'm guessing it also occurs in many other circumstances in the Groovy-->bytecode generation.
At least for these cases, the suggested improvement would be to use Integer.valueOf(0), instead of creating a new Integer each time (this happens inside a loop, inside a recursive function!!)
Many Java implementations (i.e. Sun's) return an immutable Integer from a pre-created Map of already-used integers, or for small values. For example, Sun has a pre-created list of Integer values
ranging from -128 to +127.

This small number comparisons and indexes (for example against zero) happen very often in normal algorithms and it could be a big improvement in speed and memory footprint to implement this "fix". Also, it seems to me that it's not such a complicated refactoring (but I haven't looked at the internals)

Issue Links

• is depended upon by: GROOVY-2988 Construction of integral data types