alluxio.client.file

Class FileSystemUtils

java.lang.Object

alluxio.client.file.FileSystemUtils

@ThreadSafe
public final class FileSystemUtils
extends Object

Collection of utility methods to handle with FileSystem related objects.

Method Summary

Modifier and Type	Method and Description
static List<AlluxioURI>	checkConsistency(AlluxioURI path, CheckConsistencyOptions options) Checks the consistency of Alluxio metadata against the under storage for all files and directories in a given subtree.
static void	persistFile(FileSystem fs, AlluxioURI uri) Persists the given file to the under file system.
static boolean	waitCompleted(FileSystem fs, AlluxioURI uri) Shortcut for waitCompleted(fs, uri, -1, TimeUnit.MILLISECONDS), i.e., wait for an indefinite amount of time.
static boolean	waitCompleted(FileSystem fs, AlluxioURI uri, long timeout, TimeUnit tunit) Waits for a file to be marked as completed.

Methods inherited from class java.lang.Object

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

Method Detail

waitCompleted

public static boolean waitCompleted(FileSystem fs,
                                    AlluxioURI uri)
                             throws IOException,
                                    AlluxioException,
                                    InterruptedException

Shortcut for waitCompleted(fs, uri, -1, TimeUnit.MILLISECONDS), i.e., wait for an indefinite amount of time. Note that if a file is never completed, the thread will block forever, so use with care.

Parameters:

fs - a FileSystem instance

uri - the URI of the file on which the thread should wait

Returns:

true if the file is complete when this method returns and false if the method timed out before the file was complete.

Throws:

InterruptedException - if the thread receives an interrupt while waiting for file completion

IOException

AlluxioException

See Also:

waitCompleted(FileSystem, AlluxioURI, long, TimeUnit)

waitCompleted

public static boolean waitCompleted(FileSystem fs,
                                    AlluxioURI uri,
                                    long timeout,
                                    TimeUnit tunit)
                             throws IOException,
                                    AlluxioException,
                                    InterruptedException

Waits for a file to be marked as completed.

The calling thread will block for at most timeout time units (as specified via tunit or until the file is reported as complete by the master. The method will return the last known completion status of the file (hence, false only if the method has timed out). A zero value on the timeout parameter will make the calling thread check once and return; a negative value will make it block indefinitely. Note that, in this last case, if a file is never completed, the thread will block forever, so use with care.

Note that the file whose uri is specified, might not exist at the moment this method this call. The method will deliberately block anyway for the specified amount of time, waiting for the file to be created and eventually completed. Note also that the file might be moved or deleted while it is waited upon. In such cases the method will throw the a AlluxioException

IMPLEMENTATION NOTES This method is implemented by periodically polling the master about the file status. The polling period is controlled by the PropertyKey.USER_FILE_WAITCOMPLETED_POLL_MS java property and defaults to a generous 1 second.

Parameters:

fs - an instance of FileSystem

uri - the URI of the file whose completion status is to be watied for

timeout - maximum time the calling thread should be blocked on this call

tunit - the @{link TimeUnit} instance describing the timeout parameter

Returns:

true if the file is complete when this method returns and false if the method timed out before the file was complete.

Throws:

InterruptedException - if the thread receives an interrupt while waiting for file completion

IOException

AlluxioException

persistFile

public static void persistFile(FileSystem fs,
                               AlluxioURI uri)
                        throws IOException

Persists the given file to the under file system.

Parameters:

fs - FileSystem to carry out Alluxio operations

uri - the uri of the file to persist

Throws:

IOException

checkConsistency

public static List<AlluxioURI> checkConsistency(AlluxioURI path,
                                                CheckConsistencyOptions options)
                                         throws IOException

Checks the consistency of Alluxio metadata against the under storage for all files and directories in a given subtree.

Parameters:

path - the root of the subtree to check

options - method options

Returns:

a list of inconsistent files and directories

Throws:

IOException