/// <summary>
/// This method handles the following conditions:
/// <ul>
/// <li>If retry is not to be processed, return null</li>
/// <li>If there is no cache entry, add a new entry
/// <paramref name="newEntry"/>
/// and return
/// it.</li>
/// <li>If there is an existing entry, wait for its completion. If the
/// completion state is
/// <see cref="CacheEntry.Failed"/>
/// , the expectation is that the
/// thread that waited for completion, retries the request. the
/// <see cref="CacheEntry"/>
/// state is set to
/// <see cref="CacheEntry.Inprogress"/>
/// again.
/// <li>If the completion state is
/// <see cref="CacheEntry.Success"/>
/// , the entry is
/// returned so that the thread that waits for it can can return previous
/// response.</li>
/// <ul>
/// </summary>
/// <returns>
///
/// <see cref="CacheEntry"/>
/// .
/// </returns>
private RetryCache.CacheEntry WaitForCompletion(RetryCache.CacheEntry newEntry)
{
RetryCache.CacheEntry mapEntry = null;
Lock.Lock();
try
{
mapEntry = set.Get(newEntry);
// If an entry in the cache does not exist, add a new one
if (mapEntry == null)
{
if (Log.IsTraceEnabled())
{
Log.Trace("Adding Rpc request clientId " + newEntry.clientIdMsb + newEntry.clientIdLsb
+ " callId " + newEntry.callId + " to retryCache");
}
set.Put(newEntry);
retryCacheMetrics.IncrCacheUpdated();
return(newEntry);
}
else
{
retryCacheMetrics.IncrCacheHit();
}
}
finally
{
Lock.Unlock();
}
// Entry already exists in cache. Wait for completion and return its state
Preconditions.CheckNotNull(mapEntry, "Entry from the cache should not be null");
// Wait for in progress request to complete
lock (mapEntry)
{
while (mapEntry.state == RetryCache.CacheEntry.Inprogress)
{
try
{
Runtime.Wait(mapEntry);
}
catch (Exception)
{
// Restore the interrupted status
Thread.CurrentThread().Interrupt();
}
}
// Previous request has failed, the expectation is is that it will be
// retried again.
if (mapEntry.state != RetryCache.CacheEntry.Success)
{
mapEntry.state = RetryCache.CacheEntry.Inprogress;
}
}
return(mapEntry);
}
internal static Org.Apache.Hadoop.Hdfs.Server.Namenode.INodeMap NewInstance(INodeDirectory
rootDir)
{
// Compute the map capacity by allocating 1% of total memory
int capacity = LightWeightGSet.ComputeCapacity(1, "INodeMap");
GSet <INode, INodeWithAdditionalFields> map = new LightWeightGSet <INode, INodeWithAdditionalFields
>(capacity);
map.Put(rootDir);
return(new Org.Apache.Hadoop.Hdfs.Server.Namenode.INodeMap(map));
}