Leo Li 写道:
Hi, Spark:
Yes, I think it is RI's bug.
But It should throw ConcurrentModificationException as spec says:
1. This exception may be thrown by methods that have detected
concurrent modification of an object when such modification is not
permissible.
2. Note that this exception does not always indicate that an object has
been concurrently modified by a *different* thread. If a single thread
issues a sequence of method invocations that violates the contract of an
object, the object may throw this exception. For example, if a thread
modifies a collection directly while it is iterating over the collection
with a fail-fast iterator, the iterator will throw this exception.
The iterator 's remove() action relies on the result of previous
next(), but is interrupted by the set.remove() method. I think it is the
case.
Besides, If the same thing is applied to Hashset:
public static void main(String[] args) {
HashSet set = new HashSet();
Object o = new Object();
set.add(o);
Iterator iter = set.iterator();
iter.next();
set.remove(o);
iter.remove();
}
It will throw ConcurrentModificationException as expected.:)
There is a paragraph from spec clearly states that
ConcurrentModificationException will never be thrown out from the
iterator returned
by EnumSet. Cited below:
"The returned iterator is /weakly consistent/: it will never throw
|ConcurrentModificationException| <cid:[email protected]>
and it may or may not show the effects of any modifications to the set
that occur while the iteration is in progress."
Best regards
On 8/19/06, Spark Shen <[EMAIL PROTECTED]> wrote:
Hi All:
The following behavior of RI java.util.EnumSet seems odd. Do you have
any opinion on whether it is a bug of RI?
import java.util.EnumSet;
import java.util.Iterator;
public class Test {
static enum EnumFoo {
a, b,
}
public static void main(String[] args){
EnumSet<EnumFoo> set = EnumSet.noneOf(EnumFoo.class);
set.add(EnumFoo.a);
Iterator<EnumFoo> iterator = set.iterator();
iterator.next();
set.remove(EnumFoo.a);
iterator.remove(); (1)
// The output value is true
System.out.println(set.contains(EnumFoo.a));
// The output value is 64
System.out.println(set.size());
}
}
IMHO, when (1) is executed, an IllegalStateException should be thrown
out, since the element EnumFoo.a does not exist at the moment.
Any thoughts?
Best regards
--
Spark Shen
China Software Development Lab, IBM
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Spark Shen
China Software Development Lab, IBM
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