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https://issues.apache.org/jira/browse/LANG-534?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12759445#action_12759445
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Joerg Schaible edited comment on LANG-534 at 9/25/09 2:53 AM:
--------------------------------------------------------------
bq. No, this just returns null if you give it a null array...
This is not completely true, calling
{code:java}
String[] stringArray = ArrayUtils.<String>nullToEmpty();
{code}
will return an empty array of proper type. Therefore we actually talk about a
new method that can be utilized (LANG-537):
{code:java}
public static <T> T[] toArry(T... items) {
return items;
}
public static <T> T[] nullToEmpty(T[] items) {
if (items != null)
return items;
else
return ArrayUtils.<T>toArray();
}
{code}
I've not tested the latter method, but the former definitely works for empty
arguments.
was (Author: joehni):
bq. No, this just returns null if you give it a null array...
This is not completely true, calling
{code:java}
String[] stringArray = ArrayUtils.<String>nullToEmpty();
{code}
will return an empty array of proper type. Therefore we actually talk about a
new method that can be utilized (LANG-537):
{code:java}
public static <T> T[] createArry(T... items) {
return items;
}
public static <T> T[] nullToEmpty(T[] items) {
if (items != null)
return items;
else
return ArrayUtils.<T>createArray();
}
{code}
I've not tested the latter method, but the former definitely works for empty
arguments.
> 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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