-
- All Superinterfaces:
- Comparable<Path>, Iterable<Path>, Watchable
public interface Path extends Comparable<Path>, Iterable<Path>, Watchable
An object that may be used to locate a file in a file system. It will typically represent a system dependent file path.A
Path
represents a path that is hierarchical and composed of a sequence of directory and file name elements separated by a special separator or delimiter. A root component, that identifies a file system hierarchy, may also be present. The name element that is farthest from the root of the directory hierarchy is the name of a file or directory. The other name elements are directory names. APath
can represent a root, a root and a sequence of names, or simply one or more name elements. APath
is considered to be an empty path if it consists solely of one name element that is empty. Accessing a file using an empty path is equivalent to accessing the default directory of the file system.Path
defines thegetFileName
,getParent
,getRoot
, andsubpath
methods to access the path components or a subsequence of its name elements.In addition to accessing the components of a path, a
Path
also defines theresolve
andresolveSibling
methods to combine paths. Therelativize
method that can be used to construct a relative path between two paths. Paths can becompared
, and tested against each other using thestartsWith
andendWith
methods.This interface extends
Watchable
interface so that a directory located by a path can beregistered
with aWatchService
and entries in the directory watched.WARNING: This interface is only intended to be implemented by those developing custom file system implementations. Methods may be added to this interface in future releases.
Accessing Files
Paths may be used with the
Files
class to operate on files, directories, and other types of files. For example, suppose we want aBufferedReader
to read text from a file "access.log
". The file is located in a directory "logs
" relative to the current working directory and is UTF-8 encoded.Path path = FileSystems.getDefault().getPath("logs", "access.log"); BufferReader reader = Files.newBufferedReader(path, StandardCharsets.UTF_8);
Interoperability
Paths associated with the default
provider
are generally interoperable with thejava.io.File
class. Paths created by other providers are unlikely to be interoperable with the abstract path names represented byjava.io.File
. ThetoPath
method may be used to obtain aPath
from the abstract path name represented by ajava.io.File
object. The resultingPath
can be used to operate on the same file as thejava.io.File
object. In addition, thetoFile
method is useful to construct aFile
from theString
representation of aPath
.Concurrency
Implementations of this interface are immutable and safe for use by multiple concurrent threads.
- Since:
- 1.7
- See Also:
Paths
-
-
Method Summary
Methods Modifier and Type Method and Description int
compareTo(Path other)
Compares two abstract paths lexicographically.boolean
endsWith(Path other)
Tests if this path ends with the given path.boolean
endsWith(String other)
Tests if this path ends with aPath
, constructed by converting the given path string, in exactly the manner specified by theendsWith(Path)
method.boolean
equals(Object other)
Tests this path for equality with the given object.Path
getFileName()
Returns the name of the file or directory denoted by this path as aPath
object.FileSystem
getFileSystem()
Returns the file system that created this object.Path
getName(int index)
Returns a name element of this path as aPath
object.int
getNameCount()
Returns the number of name elements in the path.Path
getParent()
Returns the parent path, ornull
if this path does not have a parent.Path
getRoot()
Returns the root component of this path as aPath
object, ornull
if this path does not have a root component.int
hashCode()
Computes a hash code for this path.boolean
isAbsolute()
Tells whether or not this path is absolute.Iterator<Path>
iterator()
Returns an iterator over the name elements of this path.Path
normalize()
Returns a path that is this path with redundant name elements eliminated.WatchKey
register(WatchService watcher, WatchEvent.Kind<?>... events)
Registers the file located by this path with a watch service.WatchKey
register(WatchService watcher, WatchEvent.Kind<?>[] events, WatchEvent.Modifier... modifiers)
Registers the file located by this path with a watch service.Path
relativize(Path other)
Constructs a relative path between this path and a given path.Path
resolve(Path other)
Resolve the given path against this path.Path
resolve(String other)
Converts a given path string to aPath
and resolves it against thisPath
in exactly the manner specified by theresolve
method.Path
resolveSibling(Path other)
Resolves the given path against this path'sparent
path.Path
resolveSibling(String other)
Converts a given path string to aPath
and resolves it against this path'sparent
path in exactly the manner specified by theresolveSibling
method.boolean
startsWith(Path other)
Tests if this path starts with the given path.boolean
startsWith(String other)
Tests if this path starts with aPath
, constructed by converting the given path string, in exactly the manner specified by thestartsWith(Path)
method.Path
subpath(int beginIndex, int endIndex)
Returns a relativePath
that is a subsequence of the name elements of this path.Path
toAbsolutePath()
Returns aPath
object representing the absolute path of this path.File
toFile()
Returns aFile
object representing this path.Path
toRealPath(LinkOption... options)
Returns the real path of an existing file.String
toString()
Returns the string representation of this path.URI
toUri()
Returns a URI to represent this path.
-
-
-
Method Detail
-
getFileSystem
FileSystem getFileSystem()
Returns the file system that created this object.- Returns:
- the file system that created this object
-
isAbsolute
boolean isAbsolute()
Tells whether or not this path is absolute.An absolute path is complete in that it doesn't need to be combined with other path information in order to locate a file.
- Returns:
true
if, and only if, this path is absolute
-
getRoot
Path getRoot()
Returns the root component of this path as aPath
object, ornull
if this path does not have a root component.- Returns:
- a path representing the root component of this path,
or
null
-
getFileName
Path getFileName()
Returns the name of the file or directory denoted by this path as aPath
object. The file name is the farthest element from the root in the directory hierarchy.- Returns:
- a path representing the name of the file or directory, or
null
if this path has zero elements
-
getParent
Path getParent()
Returns the parent path, ornull
if this path does not have a parent.The parent of this path object consists of this path's root component, if any, and each element in the path except for the farthest from the root in the directory hierarchy. This method does not access the file system; the path or its parent may not exist. Furthermore, this method does not eliminate special names such as "." and ".." that may be used in some implementations. On UNIX for example, the parent of "
/a/b/c
" is "/a/b
", and the parent of"x/y/.
" is "x/y
". This method may be used with thenormalize
method, to eliminate redundant names, for cases where shell-like navigation is required.If this path has one or more elements, and no root component, then this method is equivalent to evaluating the expression:
subpath(0, getNameCount()-1);
- Returns:
- a path representing the path's parent
-
getNameCount
int getNameCount()
Returns the number of name elements in the path.- Returns:
- the number of elements in the path, or
0
if this path only represents a root component
-
getName
Path getName(int index)
Returns a name element of this path as aPath
object.The
index
parameter is the index of the name element to return. The element that is closest to the root in the directory hierarchy has index0
. The element that is farthest from the root has indexcount
-1
.- Parameters:
index
- the index of the element- Returns:
- the name element
- Throws:
IllegalArgumentException
- ifindex
is negative,index
is greater than or equal to the number of elements, or this path has zero name elements
-
subpath
Path subpath(int beginIndex, int endIndex)
Returns a relativePath
that is a subsequence of the name elements of this path.The
beginIndex
andendIndex
parameters specify the subsequence of name elements. The name that is closest to the root in the directory hierarchy has index0
. The name that is farthest from the root has indexcount
-1
. The returnedPath
object has the name elements that begin atbeginIndex
and extend to the element at indexendIndex-1
.- Parameters:
beginIndex
- the index of the first element, inclusiveendIndex
- the index of the last element, exclusive- Returns:
- a new
Path
object that is a subsequence of the name elements in thisPath
- Throws:
IllegalArgumentException
- ifbeginIndex
is negative, or greater than or equal to the number of elements. IfendIndex
is less than or equal tobeginIndex
, or larger than the number of elements.
-
startsWith
boolean startsWith(Path other)
Tests if this path starts with the given path.This path starts with the given path if this path's root component starts with the root component of the given path, and this path starts with the same name elements as the given path. If the given path has more name elements than this path then
false
is returned.Whether or not the root component of this path starts with the root component of the given path is file system specific. If this path does not have a root component and the given path has a root component then this path does not start with the given path.
If the given path is associated with a different
FileSystem
to this path thenfalse
is returned.- Parameters:
other
- the given path- Returns:
true
if this path starts with the given path; otherwisefalse
-
startsWith
boolean startsWith(String other)
Tests if this path starts with aPath
, constructed by converting the given path string, in exactly the manner specified by thestartsWith(Path)
method. On UNIX for example, the path "foo/bar
" starts with "foo
" and "foo/bar
". It does not start with "f
" or "fo
".- Parameters:
other
- the given path string- Returns:
true
if this path starts with the given path; otherwisefalse
- Throws:
InvalidPathException
- If the path string cannot be converted to a Path.
-
endsWith
boolean endsWith(Path other)
Tests if this path ends with the given path.If the given path has N elements, and no root component, and this path has N or more elements, then this path ends with the given path if the last N elements of each path, starting at the element farthest from the root, are equal.
If the given path has a root component then this path ends with the given path if the root component of this path ends with the root component of the given path, and the corresponding elements of both paths are equal. Whether or not the root component of this path ends with the root component of the given path is file system specific. If this path does not have a root component and the given path has a root component then this path does not end with the given path.
If the given path is associated with a different
FileSystem
to this path thenfalse
is returned.- Parameters:
other
- the given path- Returns:
true
if this path ends with the given path; otherwisefalse
-
endsWith
boolean endsWith(String other)
Tests if this path ends with aPath
, constructed by converting the given path string, in exactly the manner specified by theendsWith(Path)
method. On UNIX for example, the path "foo/bar
" ends with "foo/bar
" and "bar
". It does not end with "r
" or "/bar
". Note that trailing separators are not taken into account, and so invoking this method on thePath
"foo/bar
" with theString
"bar/
" returnstrue
.- Parameters:
other
- the given path string- Returns:
true
if this path starts with the given path; otherwisefalse
- Throws:
InvalidPathException
- If the path string cannot be converted to a Path.
-
normalize
Path normalize()
Returns a path that is this path with redundant name elements eliminated.The precise definition of this method is implementation dependent but in general it derives from this path, a path that does not contain redundant name elements. In many file systems, the "
.
" and "..
" are special names used to indicate the current directory and parent directory. In such file systems all occurrences of ".
" are considered redundant. If a "..
" is preceded by a non-"..
" name then both names are considered redundant (the process to identify such names is repeated until is it no longer applicable).This method does not access the file system; the path may not locate a file that exists. Eliminating "
..
" and a preceding name from a path may result in the path that locates a different file than the original path. This can arise when the preceding name is a symbolic link.- Returns:
- the resulting path or this path if it does not contain redundant name elements; an empty path is returned if this path does have a root component and all name elements are redundant
- See Also:
getParent()
,toRealPath(java.nio.file.LinkOption...)
-
resolve
Path resolve(Path other)
Resolve the given path against this path.If the
other
parameter is anabsolute
path then this method trivially returnsother
. Ifother
is an empty path then this method trivially returns this path. Otherwise this method considers this path to be a directory and resolves the given path against this path. In the simplest case, the given path does not have aroot
component, in which case this method joins the given path to this path and returns a resulting path thatends
with the given path. Where the given path has a root component then resolution is highly implementation dependent and therefore unspecified.- Parameters:
other
- the path to resolve against this path- Returns:
- the resulting path
- See Also:
relativize(java.nio.file.Path)
-
resolve
Path resolve(String other)
Converts a given path string to aPath
and resolves it against thisPath
in exactly the manner specified by theresolve
method. For example, suppose that the name separator is "/
" and a path represents "foo/bar
", then invoking this method with the path string "gus
" will result in thePath
"foo/bar/gus
".- Parameters:
other
- the path string to resolve against this path- Returns:
- the resulting path
- Throws:
InvalidPathException
- if the path string cannot be converted to a Path.- See Also:
FileSystem.getPath(java.lang.String, java.lang.String...)
-
resolveSibling
Path resolveSibling(Path other)
Resolves the given path against this path'sparent
path. This is useful where a file name needs to be replaced with another file name. For example, suppose that the name separator is "/
" and a path represents "dir1/dir2/foo
", then invoking this method with thePath
"bar
" will result in thePath
"dir1/dir2/bar
". If this path does not have a parent path, orother
isabsolute
, then this method returnsother
. Ifother
is an empty path then this method returns this path's parent, or where this path doesn't have a parent, the empty path.- Parameters:
other
- the path to resolve against this path's parent- Returns:
- the resulting path
- See Also:
resolve(Path)
-
resolveSibling
Path resolveSibling(String other)
Converts a given path string to aPath
and resolves it against this path'sparent
path in exactly the manner specified by theresolveSibling
method.- Parameters:
other
- the path string to resolve against this path's parent- Returns:
- the resulting path
- Throws:
InvalidPathException
- if the path string cannot be converted to a Path.- See Also:
FileSystem.getPath(java.lang.String, java.lang.String...)
-
relativize
Path relativize(Path other)
Constructs a relative path between this path and a given path.Relativization is the inverse of
resolution
. This method attempts to construct arelative
path that whenresolved
against this path, yields a path that locates the same file as the given path. For example, on UNIX, if this path is"/a/b"
and the given path is"/a/b/c/d"
then the resulting relative path would be"c/d"
. Where this path and the given path do not have aroot
component, then a relative path can be constructed. A relative path cannot be constructed if only one of the paths have a root component. Where both paths have a root component then it is implementation dependent if a relative path can be constructed. If this path and the given path areequal
then an empty path is returned.For any two
normalized
paths p and q, where q does not have a root component,p.relativize(p.resolve(q)).equals(q)
When symbolic links are supported, then whether the resulting path, when resolved against this path, yields a path that can be used to locate the
same
file asother
is implementation dependent. For example, if this path is"/a/b"
and the given path is"/a/x"
then the resulting relative path may be"../x"
. If"b"
is a symbolic link then is implementation dependent if"a/b/../x"
would locate the same file as"/a/x"
.- Parameters:
other
- the path to relativize against this path- Returns:
- the resulting relative path, or an empty path if both paths are equal
- Throws:
IllegalArgumentException
- ifother
is not aPath
that can be relativized against this path
-
toUri
URI toUri()
Returns a URI to represent this path.This method constructs an absolute
URI
with ascheme
equal to the URI scheme that identifies the provider. The exact form of the scheme specific part is highly provider dependent.In the case of the default provider, the URI is hierarchical with a
path
component that is absolute. The query and fragment components are undefined. Whether the authority component is defined or not is implementation dependent. There is no guarantee that theURI
may be used to construct ajava.io.File
. In particular, if this path represents a Universal Naming Convention (UNC) path, then the UNC server name may be encoded in the authority component of the resulting URI. In the case of the default provider, and the file exists, and it can be determined that the file is a directory, then the resultingURI
will end with a slash.The default provider provides a similar round-trip guarantee to the
File
class. For a givenPath
p it is guaranteed thatPaths.get
(p.toUri()).equals(p .toAbsolutePath
())Path
, theURI
, and the newPath
are all created in (possibly different invocations of) the same Java virtual machine. Whether other providers make any guarantees is provider specific and therefore unspecified.When a file system is constructed to access the contents of a file as a file system then it is highly implementation specific if the returned URI represents the given path in the file system or it represents a compound URI that encodes the URI of the enclosing file system. A format for compound URIs is not defined in this release; such a scheme may be added in a future release.
- Returns:
- the URI representing this path
- Throws:
IOError
- if an I/O error occurs obtaining the absolute path, or where a file system is constructed to access the contents of a file as a file system, and the URI of the enclosing file system cannot be obtainedSecurityException
- In the case of the default provider, and a security manager is installed, thetoAbsolutePath
method throws a security exception.
-
toAbsolutePath
Path toAbsolutePath()
Returns aPath
object representing the absolute path of this path.If this path is already
absolute
then this method simply returns this path. Otherwise, this method resolves the path in an implementation dependent manner, typically by resolving the path against a file system default directory. Depending on the implementation, this method may throw an I/O error if the file system is not accessible.- Returns:
- a
Path
object representing the absolute path - Throws:
IOError
- if an I/O error occursSecurityException
- In the case of the default provider, a security manager is installed, and this path is not absolute, then the security manager'scheckPropertyAccess
method is invoked to check access to the system propertyuser.dir
-
toRealPath
Path toRealPath(LinkOption... options) throws IOException
Returns the real path of an existing file.The precise definition of this method is implementation dependent but in general it derives from this path, an
absolute
path that locates thesame
file as this path, but with name elements that represent the actual name of the directories and the file. For example, where filename comparisons on a file system are case insensitive then the name elements represent the names in their actual case. Additionally, the resulting path has redundant name elements removed.If this path is relative then its absolute path is first obtained, as if by invoking the
toAbsolutePath
method.The
options
array may be used to indicate how symbolic links are handled. By default, symbolic links are resolved to their final target. If the optionNOFOLLOW_LINKS
is present then this method does not resolve symbolic links. Some implementations allow special names such as "..
" to refer to the parent directory. When deriving the real path, and a "..
" (or equivalent) is preceded by a non-"..
" name then an implementation will typically cause both names to be removed. When not resolving symbolic links and the preceding name is a symbolic link then the names are only removed if it guaranteed that the resulting path will locate the same file as this path.- Parameters:
options
- options indicating how symbolic links are handled- Returns:
- an absolute path represent the real path of the file located by this object
- Throws:
IOException
- if the file does not exist or an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, itscheckRead
method is invoked to check read access to the file, and where this path is not absolute, itscheckPropertyAccess
method is invoked to check access to the system propertyuser.dir
-
toFile
File toFile()
Returns aFile
object representing this path. Where thisPath
is associated with the default provider, then this method is equivalent to returning aFile
object constructed with theString
representation of this path.If this path was created by invoking the
File
toPath
method then there is no guarantee that theFile
object returned by this method isequal
to the originalFile
.- Returns:
- a
File
object representing this path - Throws:
UnsupportedOperationException
- if thisPath
is not associated with the default provider
-
register
WatchKey register(WatchService watcher, WatchEvent.Kind<?>[] events, WatchEvent.Modifier... modifiers) throws IOException
Registers the file located by this path with a watch service.In this release, this path locates a directory that exists. The directory is registered with the watch service so that entries in the directory can be watched. The
events
parameter is the events to register and may contain the following events:ENTRY_CREATE
- entry created or moved into the directoryENTRY_DELETE
- entry deleted or moved out of the directoryENTRY_MODIFY
- entry in directory was modified
The
context
for these events is the relative path between the directory located by this path, and the path that locates the directory entry that is created, deleted, or modified.The set of events may include additional implementation specific event that are not defined by the enum
StandardWatchEventKinds
The
modifiers
parameter specifies modifiers that qualify how the directory is registered. This release does not define any standard modifiers. It may contain implementation specific modifiers.Where a file is registered with a watch service by means of a symbolic link then it is implementation specific if the watch continues to depend on the existence of the symbolic link after it is registered.
- Specified by:
register
in interfaceWatchable
- Parameters:
watcher
- the watch service to which this object is to be registeredevents
- the events for which this object should be registeredmodifiers
- the modifiers, if any, that modify how the object is registered- Returns:
- a key representing the registration of this object with the given watch service
- Throws:
UnsupportedOperationException
- if unsupported events or modifiers are specifiedIllegalArgumentException
- if an invalid combination of events or modifiers is specifiedClosedWatchServiceException
- if the watch service is closedNotDirectoryException
- if the file is registered to watch the entries in a directory and the file is not a directory (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.
-
register
WatchKey register(WatchService watcher, WatchEvent.Kind<?>... events) throws IOException
Registers the file located by this path with a watch service.An invocation of this method behaves in exactly the same way as the invocation
watchable.
register
(watcher, events, new WatchEvent.Modifier[0]);Usage Example: Suppose we wish to register a directory for entry create, delete, and modify events:
Path dir = ... WatchService watcher = ... WatchKey key = dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
- Specified by:
register
in interfaceWatchable
- Parameters:
watcher
- The watch service to which this object is to be registeredevents
- The events for which this object should be registered- Returns:
- A key representing the registration of this object with the given watch service
- Throws:
UnsupportedOperationException
- If unsupported events are specifiedIllegalArgumentException
- If an invalid combination of events is specifiedClosedWatchServiceException
- If the watch service is closedNotDirectoryException
- If the file is registered to watch the entries in a directory and the file is not a directory (optional specific exception)IOException
- If an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.
-
iterator
Iterator<Path> iterator()
Returns an iterator over the name elements of this path.The first element returned by the iterator represents the name element that is closest to the root in the directory hierarchy, the second element is the next closest, and so on. The last element returned is the name of the file or directory denoted by this path. The
root
component, if present, is not returned by the iterator.
-
compareTo
int compareTo(Path other)
Compares two abstract paths lexicographically. The ordering defined by this method is provider specific, and in the case of the default provider, platform specific. This method does not access the file system and neither file is required to exist.This method may not be used to compare paths that are associated with different file system providers.
- Specified by:
compareTo
in interfaceComparable<Path>
- Parameters:
other
- the path compared to this path.- Returns:
- zero if the argument is
equal
to this path, a value less than zero if this path is lexicographically less than the argument, or a value greater than zero if this path is lexicographically greater than the argument - Throws:
ClassCastException
- if the paths are associated with different providers
-
equals
boolean equals(Object other)
Tests this path for equality with the given object.If the given object is not a Path, or is a Path associated with a different
FileSystem
, then this method returnsfalse
.Whether or not two path are equal depends on the file system implementation. In some cases the paths are compared without regard to case, and others are case sensitive. This method does not access the file system and the file is not required to exist. Where required, the
isSameFile
method may be used to check if two paths locate the same file.This method satisfies the general contract of the
Object.equals
method.- Overrides:
equals
in classObject
- Parameters:
other
- the object to which this object is to be compared- Returns:
true
if, and only if, the given object is aPath
that is identical to thisPath
- See Also:
Object.hashCode()
,HashMap
-
hashCode
int hashCode()
Computes a hash code for this path.The hash code is based upon the components of the path, and satisfies the general contract of the
Object.hashCode
method.- Overrides:
hashCode
in classObject
- Returns:
- the hash-code value for this path
- See Also:
Object.equals(java.lang.Object)
,System.identityHashCode(java.lang.Object)
-
toString
String toString()
Returns the string representation of this path.If this path was created by converting a path string using the
getPath
method then the path string returned by this method may differ from the original String used to create the path.The returned path string uses the default name
separator
to separate names in the path.
-
-
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