/// <summary>
/// add node to the map
/// return true if the node is added; false otherwise.
/// </summary>
internal virtual bool Add(DatanodeDescriptor node)
{
hostmapLock.WriteLock().Lock();
try
{
if (node == null || Contains(node))
{
return(false);
}
string ipAddr = node.GetIpAddr();
string hostname = node.GetHostName();
mapHost[hostname] = ipAddr;
DatanodeDescriptor[] nodes = map[ipAddr];
DatanodeDescriptor[] newNodes;
if (nodes == null)
{
newNodes = new DatanodeDescriptor[1];
newNodes[0] = node;
}
else
{
// rare case: more than one datanode on the host
newNodes = new DatanodeDescriptor[nodes.Length + 1];
System.Array.Copy(nodes, 0, newNodes, 0, nodes.Length);
newNodes[nodes.Length] = node;
}
map[ipAddr] = newNodes;
return(true);
}
finally
{
hostmapLock.WriteLock().Unlock();
}
}
/// <summary>Check if node is already in the map.</summary>
internal virtual bool Contains(DatanodeDescriptor node)
{
if (node == null)
{
return(false);
}
string ipAddr = node.GetIpAddr();
hostmapLock.ReadLock().Lock();
try
{
DatanodeDescriptor[] nodes = map[ipAddr];
if (nodes != null)
{
foreach (DatanodeDescriptor containedNode in nodes)
{
if (node == containedNode)
{
return(true);
}
}
}
}
finally
{
hostmapLock.ReadLock().Unlock();
}
return(false);
}
/// <summary>
/// remove node from the map
/// return true if the node is removed; false otherwise.
/// </summary>
internal virtual bool Remove(DatanodeDescriptor node)
{
if (node == null)
{
return(false);
}
string ipAddr = node.GetIpAddr();
string hostname = node.GetHostName();
hostmapLock.WriteLock().Lock();
try
{
DatanodeDescriptor[] nodes = map[ipAddr];
if (nodes == null)
{
return(false);
}
if (nodes.Length == 1)
{
if (nodes[0] == node)
{
Sharpen.Collections.Remove(map, ipAddr);
//remove hostname key since last datanode is removed
Sharpen.Collections.Remove(mapHost, hostname);
return(true);
}
else
{
return(false);
}
}
//rare case
int i = 0;
for (; i < nodes.Length; i++)
{
if (nodes[i] == node)
{
break;
}
}
if (i == nodes.Length)
{
return(false);
}
else
{
DatanodeDescriptor[] newNodes;
newNodes = new DatanodeDescriptor[nodes.Length - 1];
System.Array.Copy(nodes, 0, newNodes, 0, i);
System.Array.Copy(nodes, i + 1, newNodes, i, nodes.Length - i - 1);
map[ipAddr] = newNodes;
return(true);
}
}
finally
{
hostmapLock.WriteLock().Unlock();
}
}