/**
* Requests a RrdDb reference for the given RRD file path.<p>
* <ul>
* <li>If the file is already open, previously returned RrdDb reference will be returned. Its usage count
* will be incremented by one.
* <li>If the file is not already open and the number of already open RRD files is less than
* {@link #INITIAL_CAPACITY}, the file will be open and a new RrdDb reference will be returned.
* If the file is not already open and the number of already open RRD files is equal to
* {@link #INITIAL_CAPACITY}, the method blocks until some RRD file is closed.
* </ul>
*
* @param path Path to existing RRD file
* @return reference for the give RRD file
* @ Thrown in case of I/O error
*/
public RrdDb requestRrdDb(String path)
{
lock (sync)
{
String canonicalPath = Util.getCanonicalPath(path);
while (!rrdMap.ContainsKey(canonicalPath) && rrdMap.Count >= capacity)
{
Thread.Sleep(10);
}
if (rrdMap.ContainsKey(canonicalPath))
{
// already open, just increase usage count
RrdEntry entry = rrdMap[canonicalPath];
entry.count++;
return(entry.rrdDb);
}
else
{
// not open, open it now and add to the map
RrdDb rrdDb = new RrdDb(canonicalPath);
rrdMap.Add(canonicalPath, new RrdEntry(rrdDb));
return(rrdDb);
}
}
}
/**
* Requests a RrdDb reference for the given path. The file will be created from
* external data (from XML dump, RRD file or RRDTool's binary RRD file).<p>
* <ul>
* <li>If the file with the path specified is already open,
* the method blocks until the file is closed.
* <li>If the file is not already open and the number of already open RRD files is less than
* {@link #INITIAL_CAPACITY}, a new RRD file will be created and a its RrdDb reference will be returned.
* If the file is not already open and the number of already open RRD files is equal to
* {@link #INITIAL_CAPACITY}, the method blocks until some RRD file is closed.
* </ul>
*
* @param path Path to RRD file which should be created
* @param sourcePath Path to external data which is to be converted to Rrd4n's native RRD file format
* @return Reference to the newly created RRD file
* @ Thrown in case of I/O error
*/
//public RrdDb requestRrdDb(String path, String sourcePath) {
// lock (sync)
// {
// String canonicalPath = Util.getCanonicalPath(path);
// while (rrdMap.containsKey(canonicalPath) || rrdMap.size() >= capacity)
// {
// Thread.Sleep(10);
// }
// RrdDb rrdDb = new RrdDb(canonicalPath, sourcePath);
// rrdMap.put(canonicalPath, new RrdEntry(rrdDb));
// return rrdDb;
// }
//}
/**
* Releases RrdDb reference previously obtained from the pool. When a reference is released, its usage
* count is decremented by one. If usage count drops to zero, the underlying RRD file will be closed.
*
* @param rrdDb RrdDb reference to be returned to the pool
* @ Thrown in case of I/O error
*/
public void release(RrdDb rrdDb)
{
lock (sync)
{
// null pointer should not kill the thread, just ignore it
if (rrdDb == null)
{
return;
}
String canonicalPath = Util.getCanonicalPath(rrdDb.getPath());
if (!rrdMap.ContainsKey(canonicalPath))
{
throw new ApplicationException("Could not release [" + canonicalPath + "], the file was never requested");
}
RrdEntry entry = rrdMap[canonicalPath];
if (--entry.count <= 0)
{
// no longer used
rrdMap.Remove(canonicalPath);
entry.rrdDb.close();
}
}
}
private void Add(string keypath, RrdDb rrdDb)
{
RrdEntry newEntry = new RrdEntry(rrdDb);
Debug("NEW: " + newEntry.Dump());
rrdMap.Add(keypath, newEntry);
GC();
}