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From "Brian Carrier (JIRA)" <j...@apache.org>
Subject [jira] Resolved: (PDFBOX-403) Findbugs reported a minor performance issue. Integer.valueOf(string);
Date Wed, 04 Feb 2009 20:57:59 GMT

     [ https://issues.apache.org/jira/browse/PDFBOX-403?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Brian Carrier resolved PDFBOX-403.
----------------------------------

    Resolution: Later

The proposed solution uses a method introduced in Java 1.5.  The current code base is 1.4-compliant,
so it can't be used. Marking as "Later" in case PDFBox relaxes the 1.4 requirement.

> Findbugs reported a minor performance issue. Integer.valueOf(string);
> ---------------------------------------------------------------------
>
>                 Key: PDFBOX-403
>                 URL: https://issues.apache.org/jira/browse/PDFBOX-403
>             Project: PDFBox
>          Issue Type: Improvement
>          Components: PDModel
>    Affects Versions: 0.8.0-incubator
>         Environment: all
>            Reporter: Peter_Lenahan@ibi.com
>            Priority: Trivial
>
> Below are the comments from Findbugs, PMD also reported the same problem, but findbugs
gives a better description of the issue.
> -------------------------------------------------------------------
> [M P Bx] Method invokes inefficient Number constructor; use static valueOf instead [DM_NUMBER_CTOR]
> Using new Integer(int) is guaranteed to always result in a new object whereas Integer.valueOf(int)
allows caching of values to be done by the compiler, class library, or JVM. Using of cached
values avoids object allocation and the code will be faster. 
> Values between -128 and 127 are guaranteed to have corresponding cached instances and
using valueOf is approximately 3.5 times faster than using constructor. For values outside
the constant range the performance of both styles is the same. 
> Unless the class must be compatible with JVMs predating Java 1.5, use either autoboxing
or the valueOf() method when creating instances of Long, Integer, Short, Character, and Byte.
>     public Integer getRotation()
>     {
>         Integer retval = null;
>         COSNumber value = (COSNumber)page.getDictionaryObject(
> COSName.ROTATE );
>         if( value != null )
>         {
> //Change this:
>             retval = new Integer( value.intValue() ); // to this, so the first 127 rotation
numbers will be cached Integer
> values:
>             retval = Integer.valueOf(value.intValue());
>         }
>         return retval;
>     }

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