[jbosscache-issues] [JBoss JIRA] (JBCACHE-398) Cached collections don't handle null values correctly

[Scott Marlow (JIRA)]

     [ https://issues.jboss.org/browse/JBCACHE-398?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Scott Marlow reassigned JBCACHE-398:
------------------------------------

    Assignee: Scott Marlow  (was: Scott Marlow (Novell))

    
> Cached collections don't handle null values correctly
> -----------------------------------------------------
>
>                 Key: JBCACHE-398
>                 URL: https://issues.jboss.org/browse/JBCACHE-398
>             Project: JBoss Cache
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: Legacy POJO Cache 
>    Affects Versions: 1.2.4SP1
>            Reporter: twundke
>            Assignee: Scott Marlow
>             Fix For: 1.3.0.GA
>
>
> When a null value is placed into a cached collection (CachedListImpl etc), the node for that element is removed from the cache. This is because TreeCacheAopDelegate._putObject() calls _removeObject() when provided with a null value.
> This behaviour breaks size() in the case where a collection allows null values to be stored (ArrayList, HashMap etc). The cache needs to explicitly store a null object (eg. org.jboss.util.Null) so that collections work as expected.
> I have a fix, which basically involves calling the following methods in the correct places:
>    private Object toNullObject( Object aObject )
>    {
>       if ( aObject == null )
>       {
>          return Null.VALUE;
>       } // if
>       else
>       {
>          return aObject;
>       } // else
>    } // toNullObject
>    private Object toNullValue( Object aObject )
>    {
>       if ( Null.VALUE.equals( aObject ) )
>       {
>          return null;
>       } // if
>       else
>       {
>          return aObject;
>       } // else
>    } // toNullObject
> So, for example, we can use:
>   public Object get() {
>     ...
>     return toNullValue(cache_.getObject(...));
>   }
> These methods should be placed in a common area to be called by each collection class. In addition to this, the CachedListImpl.checkArgument(Object) method should be removed.

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