[DISCOVERY-3] [discovery] Enumeration in Service broken

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Nightly Builds
• Fix Version/s: 0.5

Environment

Operating System: other
Platform: Other

• Bugzilla Id: 25357
• Assignee: Simone Tripodi
• Reporter: matthew_pocock
• Created: 09/Dec/03 20:41
• Updated: 01/Jun/11 20:41
• Resolved: 08/Apr/11 06:53

Description

The Enumeration in org.apache.commons.discovery.tools.Service is broken - it
will only work in the (admittedly common) case where you do:

while(e.hasMoreElements()) e.nextElement();

If you repeatedly call nextElement(), you will get the wrong results. In
particular, this uggly but technically correct code will fail to behave sanely:

try

{ while(true) e.nextElement(); }

catch (NoSuchElementException e) {
}

The code needs hacking arround to look something more like this:

return new Enumeration() {
private Object object = getNextClassInstance();

public boolean hasMoreElements()

{ return object != null; }

public Object nextElement() {
if(object == null)

{ throw new NoSuchElementException(); }

Object obj = object;
object = getNextClassInstance();
return obj;
}

private Object getNextClassInstance()

{ // as before }

};