org.apache.hadoop.util

类 DiskChecker

java.lang.Object

org.apache.hadoop.util.DiskChecker

public class DiskChecker
extends Object

Class that provides utility functions for checking disk problem

嵌套类概要

嵌套类

限定符和类型	类和说明
static class	DiskChecker.DiskErrorException
static class	DiskChecker.DiskOutOfSpaceException

构造器概要

构造器

构造器和说明
DiskChecker()

方法概要

方法

限定符和类型	方法和说明
static void	checkDir(File dir) Create the directory if it doesn't exist and
static void	checkDir(LocalFileSystem localFS, Path dir, FsPermission expected) Create the local directory if necessary, check permissions and also ensure it can be read from and written into.
static boolean	mkdirsWithExistsAndPermissionCheck(LocalFileSystem localFS, Path dir, FsPermission expected) Create the directory or check permissions if it already exists.
static boolean	mkdirsWithExistsCheck(File dir) The semantics of mkdirsWithExistsCheck method is different from the mkdirs method provided in the Sun's java.io.File class in the following way: While creating the non-existent parent directories, this method checks for the existence of those directories if the mkdir fails at any point (since that directory might have just been created by some other process).

从类继承的方法 java.lang.Object

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

构造器详细资料

DiskChecker

public DiskChecker()

方法详细资料

mkdirsWithExistsCheck

public static boolean mkdirsWithExistsCheck(File dir)

The semantics of mkdirsWithExistsCheck method is different from the mkdirs method provided in the Sun's java.io.File class in the following way: While creating the non-existent parent directories, this method checks for the existence of those directories if the mkdir fails at any point (since that directory might have just been created by some other process). If both mkdir() and the exists() check fails for any seemingly non-existent directory, then we signal an error; Sun's mkdir would signal an error (return false) if a directory it is attempting to create already exists or the mkdir fails.

参数:

dir -

返回:

true on success, false on failure

checkDir

public static void checkDir(File dir)
                     throws DiskChecker.DiskErrorException

Create the directory if it doesn't exist and

参数:

dir -

抛出:

DiskChecker.DiskErrorException

mkdirsWithExistsAndPermissionCheck

public static boolean mkdirsWithExistsAndPermissionCheck(LocalFileSystem localFS,
                                         Path dir,
                                         FsPermission expected)
                                                  throws IOException

Create the directory or check permissions if it already exists. The semantics of mkdirsWithExistsAndPermissionCheck method is different from the mkdirs method provided in the Sun's java.io.File class in the following way: While creating the non-existent parent directories, this method checks for the existence of those directories if the mkdir fails at any point (since that directory might have just been created by some other process). If both mkdir() and the exists() check fails for any seemingly non-existent directory, then we signal an error; Sun's mkdir would signal an error (return false) if a directory it is attempting to create already exists or the mkdir fails.

参数:

localFS - local filesystem

dir - directory to be created or checked

expected - expected permission

返回:

true on success, false on failure

抛出:

IOException

checkDir

public static void checkDir(LocalFileSystem localFS,
            Path dir,
            FsPermission expected)
                     throws DiskChecker.DiskErrorException,
                            IOException

Create the local directory if necessary, check permissions and also ensure it can be read from and written into.

参数:

localFS - local filesystem

dir - directory

expected - permission

抛出:

DiskChecker.DiskErrorException

IOException