org.apache.hadoop.filecache
Class TaskDistributedCacheManager

java.lang.Object
  org.apache.hadoop.filecache.TaskDistributedCacheManager

public class TaskDistributedCacheManager
extends Object

Helper class of TrackerDistributedCacheManager that represents the cached files of a single job. This class is internal to Hadoop, and should not be treated as a public interface.

Method Summary

List<String>	getClassPaths() Retrieves class paths (as local references) to add.
ClassLoader	makeClassLoader(ClassLoader parent) Creates a class loader that includes the designated files and archives.
void	release() Releases the cached files/archives, so that space can be reclaimed by the TrackerDistributedCacheManager.
void	setSizes(long[] sizes)
void	setupCache(Configuration taskConf, String publicCacheSubdir, String privateCacheSubdir) Retrieve public distributed cache files into the local cache and updates the task configuration (which has been passed in via the constructor).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

setupCache

public void setupCache(Configuration taskConf,
                       String publicCacheSubdir,
                       String privateCacheSubdir)
                throws IOException

Retrieve public distributed cache files into the local cache and updates the task configuration (which has been passed in via the constructor). The private distributed cache is just looked at and the paths where the files/archives should go to is decided here. The actual localization is done by JobLocalizer. It is the caller's responsibility to re-write the task configuration XML file, if necessary.

Throws:

IOException

getClassPaths

public List<String> getClassPaths()
                           throws IOException

Retrieves class paths (as local references) to add. Should be called after setup().

Throws:

IOException

release

public void release()
             throws IOException

Releases the cached files/archives, so that space can be reclaimed by the TrackerDistributedCacheManager.

Throws:

IOException

setSizes

public void setSizes(long[] sizes)
              throws IOException

Throws:

IOException

makeClassLoader

public ClassLoader makeClassLoader(ClassLoader parent)
                            throws MalformedURLException

Creates a class loader that includes the designated files and archives.

Throws:

MalformedURLException