[COLLECTIONS-246] LoopingListIterator behaves unexpected on next and previous mixed

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Invalid
• Affects Version/s: 3.2
• Component/s: Iterator

Environment

JDK 1.4.2_12
Common Collections 3.2

• Assignee: Unassigned
• Reporter: Frank Hefter
• Created: 20/Mar/07 09:07
• Updated: 28/Feb/13 19:52
• Resolved: 26/Apr/08 15:17

Description

Using ArrayList as the backing list.
This combination at least returns unexpected results as you can see in the testcase below.
I used this for a list navigator in a web frontend and had trouble with users.
I suspect java.util.AbstrList$ListItr (role of "cursor" var seems to be wrong implemented ) to cause this problem. If so maybe we have to implement it in a different way.

Testcase (it runs without hassle but the comments show whats wrong):
-------------------------------------------
import java.util.ArrayList;
import junit.framework.TestCase;
import org.apache.commons.collections.iterators.LoopingListIterator;

public class SelectionControllerTest extends TestCase {
public void testSelectorForApache()

{ ArrayList al = new ArrayList(); al.add("0"); al.add("1"); al.add("2"); LoopingListIterator it = new LoopingListIterator(al); assertEquals("0", it.next()); // This is OK // here I am on "0" assertEquals("0", it.previous()); // Wrong ! This should be 2! // here I am on "0" too! This is wrong. assertEquals("2", it.previous()); assertEquals("1", it.previous()); assertEquals("0", it.previous()); assertEquals("2", it.previous()); // here I am on "2" assertEquals("2", it.next()); // Wrong ! This should be 0! // here I am on "2" too! This is wrong. assertEquals("0", it.next()); assertEquals("1", it.next()); // here I am on "1" assertEquals("1", it.previous()); // Wrong ! This should be 0! }

}
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Thanks for your help.

Issue Links

• is related to: COLLECTIONS-239 In LinkIterator hasPrevious() is not working properly for the first entry