public virtual double Remove(E key)
{
AtomicDouble atomic = map[key];
if (atomic == null)
{
return(defaultReturnValue);
}
for (; ;)
{
double oldValue = atomic.Get();
if (oldValue == 0.0 || atomic.CompareAndSet(oldValue, 0.0))
{
// only remove after setting to zero, to avoid concurrent updates
Sharpen.Collections.Remove(map, key, atomic);
// succeed even if the remove fails, since the value was already adjusted
totalCount.AddAndGet(-1.0 * oldValue);
return(oldValue);
}
}
}
public virtual double LogIncrementCount(E key, double value)
{
// TODO Inspired by Guava.AtomicLongMap
// Modify for our use?
for (; ;)
{
AtomicDouble atomic = map[key];
if (atomic == null)
{
atomic = map.PutIfAbsent(key, new AtomicDouble(value));
if (atomic == null)
{
totalCount.AddAndGet(value);
return(value);
}
}
for (; ;)
{
double oldValue = atomic.Get();
if (oldValue == 0.0)
{
// don't compareAndSet a zero
if (map.Replace(key, atomic, new AtomicDouble(value)))
{
totalCount.AddAndGet(value);
return(value);
}
goto outer_continue;
}
double newValue = SloppyMath.LogAdd(oldValue, value);
if (atomic.CompareAndSet(oldValue, newValue))
{
totalCount.AddAndGet(value);
return(newValue);
}
}
outer_continue :;
}
outer_break :;
}
public virtual double GetCount(object key)
{
AtomicDouble v = map[key];
return(v == null ? defaultReturnValue : v.Get());
}
public ConcurrentHashCounter(int initialCapacity)
{
map = new ConcurrentHashMap <E, AtomicDouble>(initialCapacity);
totalCount = new AtomicDouble();
}
