alluxio.util.io

Class PathUtils

java.lang.Object

alluxio.util.io.PathUtils

@ThreadSafe
public final class PathUtils
extends Object

Utilities related to both Alluxio paths like AlluxioURI and local file paths.

Method Summary

Modifier and Type	Method and Description
static String	cleanPath(String path) Checks and normalizes the given path.
static String	concatPath(Object base, Object... paths) Joins each element in paths in order, separated by AlluxioURI.SEPARATOR.
static String	concatPath(Object base, Object path) Joins two path elements, separated by AlluxioURI.SEPARATOR.
static AlluxioURI	findLowestCommonAncestor(Collection<AlluxioURI> paths)
static String	getParent(String path) Gets the parent of the file at a path.
static String[]	getPathComponents(String path) Gets the path components of the given path.
static String	getPermanentFileName(String path)
static boolean	hasPrefix(String path, String prefix) Checks whether the given path contains the given prefix.
static boolean	isRoot(String path) Checks if the given path is the root.
static boolean	isTemporaryFileName(String path) Determines whether the given path is a temporary file name generated by Alluxio.
static String	normalizePath(String path, String separator) Adds a trailing separator if it does not exist in path.
static String	subtractPaths(String path, String prefix) Removes the prefix from the path, yielding a relative path from the second path to the first.
static String	temporaryFileName(long nonce, String path) Generates a deterministic temporary file name for the a path and a file id and a nonce.
static String	uniqPath() Creates a unique path based off the caller.
static void	validatePath(String path) Checks if the given path is properly formed.

Methods inherited from class java.lang.Object

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

Method Detail

cleanPath

public static String cleanPath(String path)
                        throws InvalidPathException

Checks and normalizes the given path.

Parameters:

path - The path to clean up

Returns:

a normalized version of the path, with single separators between path components and dot components resolved

Throws:

InvalidPathException - if the path is invalid

concatPath

public static String concatPath(Object base,
                                Object path)
                         throws IllegalArgumentException

Joins two path elements, separated by AlluxioURI.SEPARATOR.

Note that empty element in base or paths is ignored.

Parameters:

base - base path

path - path element to concatenate

Returns:

joined path

Throws:

IllegalArgumentException - if base or paths is null

concatPath

public static String concatPath(Object base,
                                Object... paths)
                         throws IllegalArgumentException

Joins each element in paths in order, separated by AlluxioURI.SEPARATOR.

For example,

 
 concatPath("/myroot/", "dir", 1L, "filename").equals("/myroot/dir/1/filename");
 concatPath("alluxio://myroot", "dir", "filename").equals("alluxio://myroot/dir/filename");
 concatPath("myroot/", "/dir/", "filename").equals("myroot/dir/filename");
 concatPath("/", "dir", "filename").equals("/dir/filename");
 
 

Note that empty element in base or paths is ignored.

Parameters:

base - base path

paths - paths to concatenate

Returns:

joined path

Throws:

IllegalArgumentException - if base or paths is null

findLowestCommonAncestor

public static AlluxioURI findLowestCommonAncestor(Collection<AlluxioURI> paths)

Parameters:

paths - the set of paths

Returns:

the lowest common ancestor, or null if paths is null or empty

getParent

public static String getParent(String path)
                        throws InvalidPathException

Gets the parent of the file at a path.

Parameters:

path - The path

Returns:

the parent path of the file; this is "/" if the given path is the root

Throws:

InvalidPathException - if the path is invalid

getPathComponents

public static String[] getPathComponents(String path)
                                  throws InvalidPathException

Gets the path components of the given path. The first component will be an empty string. "/a/b/c" => {"", "a", "b", "c"} "/" => {""}

Parameters:

path - The path to split

Returns:

the path split into components

Throws:

InvalidPathException - if the path is invalid

subtractPaths

public static String subtractPaths(String path,
                                   String prefix)
                            throws InvalidPathException

Removes the prefix from the path, yielding a relative path from the second path to the first. If the paths are the same, this method returns the empty string.

Parameters:

path - the full path

prefix - the prefix to remove

Returns:

the path with the prefix removed

Throws:

InvalidPathException - if either of the arguments are not valid paths

hasPrefix

public static boolean hasPrefix(String path,
                                String prefix)
                         throws InvalidPathException

Checks whether the given path contains the given prefix. The comparison happens at a component granularity; for example, hasPrefix(/dir/file, /dir) should evaluate to true, while hasPrefix(/dir/file, /d) should evaluate to false.

Parameters:

path - a path

prefix - a prefix

Returns:

whether the given path has the given prefix

Throws:

InvalidPathException - when the path or prefix is invalid

isRoot

public static boolean isRoot(String path)
                      throws InvalidPathException

Checks if the given path is the root.

Parameters:

path - The path to check

Returns:

true if the path is the root

Throws:

InvalidPathException - if the path is invalid

validatePath

public static void validatePath(String path)
                         throws InvalidPathException

Checks if the given path is properly formed.

Parameters:

path - The path to check

Throws:

InvalidPathException - If the path is not properly formed

temporaryFileName

public static String temporaryFileName(long nonce,
                                       String path)

Generates a deterministic temporary file name for the a path and a file id and a nonce.

Parameters:

nonce - a nonce token

path - a file path

Returns:

a deterministic temporary file name

getPermanentFileName

public static String getPermanentFileName(String path)

Parameters:

path - the path of the file, possibly temporary

Returns:

the permanent path of the file if it was temporary, or the original path if it was not

isTemporaryFileName

public static boolean isTemporaryFileName(String path)

Determines whether the given path is a temporary file name generated by Alluxio.

Parameters:

path - the path to check

Returns:

whether the given path is a temporary file name generated by Alluxio

uniqPath

public static String uniqPath()

Creates a unique path based off the caller.

Returns:

unique path based off the caller

normalizePath

public static String normalizePath(String path,
                                   String separator)

Adds a trailing separator if it does not exist in path.

Parameters:

path - the file name

separator - trailing separator to add

Returns:

updated path with trailing separator