[jboss-jira] [JBoss JIRA] Closed: (JBRULES-722) NullPointerException when using inserAfter method with an empty LinkedList

[Edson Tirelli (JIRA)]

     [ http://jira.jboss.com/jira/browse/JBRULES-722?page=all ]

Edson Tirelli closed JBRULES-722.
---------------------------------


> NullPointerException when using inserAfter method with an empty LinkedList
> --------------------------------------------------------------------------
>
>                 Key: JBRULES-722
>                 URL: http://jira.jboss.com/jira/browse/JBRULES-722
>             Project: JBoss Rules
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>    Affects Versions: 3.1-m1
>         Environment: Windows, jdk 1.5
>            Reporter: Pierre Paysant-Le Roux
>         Assigned To: Edson Tirelli
>             Fix For: 3.1-m2
>
>
> JBoss rules throws a NullPointerException when adding my rules file. The problem is with the inserAfter methode in LinkedList. Debug shows that it appends when inserting a node in an empty list.
> I wrote a simple test case to illustrate the problem :
> Index: drools-core/src/test/java/org/drools/util/LinkedListTest.java
> ===================================================================
> --- drools-core/src/test/java/org/drools/util/LinkedListTest.java	(revision 9968)
> +++ drools-core/src/test/java/org/drools/util/LinkedListTest.java	(working copy)
> @@ -264,4 +264,7 @@
>                               3 );
>      }
> -}
> \ No newline at end of file
> +    public void testInsertAfter(){
> +	this.list.insertAfter( null, this.node1 );
> +    }
> +}
> And a patch to avoid the problem :
> Index: drools-core/src/main/java/org/drools/util/LinkedList.java
> ===================================================================
> --- drools-core/src/main/java/org/drools/util/LinkedList.java	(revision 9968)
> +++ drools-core/src/main/java/org/drools/util/LinkedList.java	(working copy)
> @@ -151,17 +151,21 @@
>          }
>  
>          if ( existingNode == null ) {
> -            // if existing node is null, then insert it as a first node
> -            final LinkedListNode node = this.firstNode;
> -            node.setPrevious( newNode );
> -            newNode.setNext( node );
> -            this.firstNode = newNode;
> +        	if(this.isEmpty())
> +        		this.firstNode = newNode;
> +        		this.lastNode = newNode;
> +        	else{
> +        		// if existing node is null, then insert it as a first node
> +        		final LinkedListNode node = this.firstNode;
> +        		node.setPrevious( newNode );
> +        		newNode.setNext( node );
> +        		this.firstNode = newNode;
> +        	}
>          } else if ( existingNode == this.lastNode ) {
>          	existingNode.setNext(newNode);
>          	newNode.setPrevious( existingNode );
>          	this.lastNode = newNode;
>          } else {
> -            ((LinkedListNode)existingNode.getNext()).setPrevious( newNode );
> +        	((LinkedListNode)existingNode.getNext()).setPrevious( newNode );
>              newNode.setNext( existingNode.getNext() );
>              existingNode.setNext( newNode );
>              newNode.setPrevious( existingNode );
> Excuse me if I'm wrong.

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