LocalCacheDirectoryManager (Apache Hadoop YARN NodeManager 2.8.0 API)

java.lang.Object
- org.apache.hadoop.yarn.server.nodemanager.containermanager.localizer.LocalCacheDirectoryManager

```
public class LocalCacheDirectoryManager
extends Object
```
LocalCacheDirectoryManager is used for managing hierarchical directories for local cache. It will allow to restrict the number of files in a directory to YarnConfiguration.NM_LOCAL_CACHE_MAX_FILES_PER_DIRECTORY which includes 36 sub-directories (named from 0 to 9 and a to z). Root directory is represented by an empty string. It internally maintains a vacant directory queue. As soon as the file count for the directory reaches its limit; new files will not be created in it until at least one file is deleted from it. New sub directories are not created unless a getRelativePathForLocalization() request is made and nonFullDirectories are empty. Note : this structure only returns relative localization path but doesn't create one on disk.

Fields
Modifier and Type	Field and Description
`static int`	`DIRECTORIES_PER_LEVEL`

Constructors
Constructor and Description
`LocalCacheDirectoryManager(org.apache.hadoop.conf.Configuration conf)`

Methods
Modifier and Type	Method and Description
`void`	`decrementFileCountForPath(String relPath)` This method will reduce the file count for the directory represented by path.
`static org.apache.hadoop.fs.Path`	`getCacheDirectoryRoot(org.apache.hadoop.fs.Path path)` Given a path to a directory within a local cache tree return the root of the cache directory.
`String`	`getRelativePathForLocalization()` This method will return relative path from the first available vacant directory.
`void`	`incrementFileCountForPath(String relPath)` Increment the file count for a relative directory within the cache

Class LocalCacheDirectoryManager