[
https://issues.apache.org/jira/browse/LANG-534?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12759713#action_12759713
]
Levon Karayan commented on LANG-534:
------------------------------------
Sorry I should have been more clear.
It's too bad that it won't work for this case, so we're still left with the
per-type implementations. BTW, should I add the @since/@author/"@param T" tags
to the patch?
His toArray method works when you know the types of objects during compile
time, and is a creative way to get a list of objects into an type safe array
using generics. I think it would be a nice addition to ArrayUtils
https://issues.apache.org/jira/browse/LANG-537
{code}
public class TypedArray {
public static void main(String[] args) {
String[] sa = null;
for (String s : TypedArray.<String>toArray()) {
System.out.println("This should never print");
}
System.out.println(
TypedArray.<String>toArray().getClass().getName() );
}
public static <T> T[] toArray(T... items) {
return items;
}
{code}
On my system:
{code}
[Ljava.lang.String;
{code}
As a side point: Even if we could somehow use generics to break it down to one
method, I'm still scratching my head as to how I could get the class empty
array constants out of nullToEmpty. Identifying the input type using
instanceof, getClass seems to be a challenge, as well as trying to stuff the
constants into the return.
> 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: New Feature
> Reporter: Levon Karayan
> Priority: Trivial
> Fix For: 3.0
>
> 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
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
