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From "Joerg Schaible (JIRA)" <j...@apache.org>
Subject [jira] Updated: (LANG-534) ArrayUtils should have method to convert null arrays to empty ones to help with Defensive coding
Date Fri, 25 Sep 2009 14:35:16 GMT

     [ https://issues.apache.org/jira/browse/LANG-534?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Joerg Schaible updated LANG-534:
--------------------------------

    Comment: was deleted

(was: Unfortunately, the latter does not work either, because the Sun compiler cannot deduce
the generic type here and will again produce an Object[0] instance. Even worse, some of the
expressions can be compiled and run from within Eclipse, but not when using the Sun compiler.

{code:java}
public class Arbitrary {
  public static <T> T[] createArray(T... items) {
    return ArrayUtils.toArray(items);
  }
  public static void main(String[] args) {
    String[] sa1 = ArrayUtils.<String>toArray(); // fine
    System.println(sa1.length);
    String[] sa2 = Arbitrary.<String>createArray(); // works in Eclipse, fails with
CCE when compiled and run with Sun JDK 1.5
    System.println(sa2.length);
  }
}
{code})

> ArrayUtils should have method to convert null arrays to empty ones to help with Defensive
coding
> ------------------------------------------------------------------------------------------------
>
>                 Key: LANG-534
>                 URL: https://issues.apache.org/jira/browse/LANG-534
>             Project: Commons Lang
>          Issue Type: Improvement
>            Reporter: Levon Karayan
>            Priority: Trivial
>         Attachments: 20090920LevonArrayUtils-nullToEmpty.patch
>
>
> There are APIs that I've come across that return <code>null</code> Arrays
in the event where there are no results.  Often these APIs correctly throw exceptions when
there is an "exceptional event", but no results isn't exceptional, and it often shouldn't
be.   This causes the programmer to make extra tests for null throughout the code to deal
with the null case, and sometimes these null cases are added after a customer searched for
gobleygook and got a NullPointerException.  It's just far cleaner/safer to convert these null
arrays to empty arrays.
> Another benefit to this method is that if the array being passed in is actually already
an empty array, it will swap the pointer for the <code>static final</code> in
the ArrayUtils class to help decrease memory fragmentation.
> e.g.
> BEFORE:
> try
> {
>   results = customer.getResults(query);
> } catch ( IOException ioex ) {
>   //  ...
> }
> if ( null == results )
> {
>    results = new int[0]{};
> }
> // do stuff
> AFTER
> try
> {
>   results = ArrayUtils.nullToEmpty(customer.getResults(query));
> } catch ( IOException ioex ) {
>   //  ...
> }
> // do stuff

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