- All Superinterfaces:
Comparable<Path>
,Iterable<Path>
,Watchable
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. A Path
can represent a
root, a root and a sequence of names, or simply one or more name elements.
A Path
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 the getFileName
,
getParent
, getRoot
, and subpath
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 the resolve
and resolveSibling
methods to combine paths. The relativize
method that can be used to construct a relative path between two paths.
Paths can be compared
, and tested against each other using
the startsWith
and endsWith
methods.
This interface extends Watchable
interface so that a directory
located by a path can be registered
with a WatchService
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 a BufferedReader
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"); BufferedReader reader = Files.newBufferedReader(path, StandardCharsets.UTF_8);
Interoperability
Paths associated with the default provider
are generally interoperable
with the java.io.File
class. Paths created by other
providers are unlikely to be interoperable with the abstract path names
represented by java.io.File
. The toPath
method may be used to obtain a Path
from the abstract path name
represented by a java.io.File
object. The resulting Path
can
be used to operate on the same file as the java.io.File
object. In
addition, the toFile
method is useful to construct a
File
from the String
representation of a Path
.
Concurrency
Implementations of this interface are immutable and safe for use by multiple concurrent threads.
- Since:
- 1.7
-
Method Summary
Modifier and TypeMethodDescriptionint
Compares two abstract paths lexicographically.default boolean
Tests if this path ends with aPath
, constructed by converting the given path string, in exactly the manner specified by theendsWith(Path)
method.boolean
Tests if this path ends with the given path.boolean
Tests this path for equality with the given object.Returns the name of the file or directory denoted by this path as aPath
object.Returns the file system that created this object.getName
(int index) Returns a name element of this path as aPath
object.int
Returns the number of name elements in the path.Returns the parent path, ornull
if this path does not have a parent.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
Tells whether or not this path is absolute.iterator()
Returns an iterator over the name elements of this path.Returns a path that is this path with redundant name elements eliminated.static Path
Returns aPath
by converting a path string, or a sequence of strings that when joined form a path string.static Path
Returns aPath
by converting a URI.default WatchKey
register
(WatchService watcher, WatchEvent.Kind<?>... events) Registers the file located by this path with a watch service.register
(WatchService watcher, WatchEvent.Kind<?>[] events, WatchEvent.Modifier... modifiers) Registers the file located by this path with a watch service.relativize
(Path other) Constructs a relative path between this path and a given path.default Path
Converts a given path string to aPath
and resolves it against thisPath
in exactly the manner specified by theresolve
method.Resolve the given path against this path.default 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.default Path
resolveSibling
(Path other) Resolves the given path against this path'sparent
path.default 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.boolean
startsWith
(Path other) Tests if this path starts with the given path.subpath
(int beginIndex, int endIndex) Returns a relativePath
that is a subsequence of the name elements of this path.Returns aPath
object representing the absolute path of this path.default File
toFile()
Returns aFile
object representing this path.toRealPath
(LinkOption... options) Returns the real path of an existing file.toString()
Returns the string representation of this path.toUri()
Returns a URI to represent this path.Methods declared in interface java.lang.Iterable
forEach, spliterator
-
Method Details
-
of
Returns aPath
by converting a path string, or a sequence of strings that when joined form a path string. Ifmore
does not specify any elements then the value of thefirst
parameter is the path string to convert. Ifmore
specifies one or more elements then each non-empty string, includingfirst
, is considered to be a sequence of name elements and is joined to form a path string. The details as to how the Strings are joined is provider specific but typically they will be joined using thename-separator
as the separator. For example, if the name separator is "/
" andgetPath("/foo","bar","gus")
is invoked, then the path string"/foo/bar/gus"
is converted to aPath
. APath
representing an empty path is returned iffirst
is the empty string andmore
does not contain any non-empty strings.The
Path
is obtained by invoking thegetPath
method of thedefault
FileSystem
.Note that while this method is very convenient, using it will imply an assumed reference to the default
FileSystem
and limit the utility of the calling code. Hence it should not be used in library code intended for flexible reuse. A more flexible alternative is to use an existingPath
instance as an anchor, such as:Path dir = ... Path path = dir.resolve("file");
- Parameters:
first
- the path string or initial part of the path stringmore
- additional strings to be joined to form the path string- Returns:
- the resulting
Path
- Throws:
InvalidPathException
- if the path string cannot be converted to aPath
- Since:
- 11
- See Also:
-
of
Returns aPath
by converting a URI.This method iterates over the
installed
providers to locate the provider that is identified by the URIscheme
of the given URI. URI schemes are compared without regard to case. If the provider is found then itsgetPath
method is invoked to convert the URI.In the case of the default provider, identified by the URI scheme "file", the given URI has a non-empty path component, and undefined query and fragment components. Whether the authority component may be present is platform specific. The returned
Path
is associated with thedefault
file system.The default provider provides a similar round-trip guarantee to the
File
class. For a givenPath
p it is guaranteed that
so long as the originalPath.of(
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.- Parameters:
uri
- the URI to convert- Returns:
- the resulting
Path
- Throws:
IllegalArgumentException
- if preconditions on theuri
parameter do not hold. The format of the URI is provider specific.FileSystemNotFoundException
- The file system, identified by the URI, does not exist and cannot be created automatically, or the provider identified by the URI's scheme component is not installedSecurityException
- if a security manager is installed and it denies an unspecified permission to access the file system- Since:
- 11
-
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 more than one element, 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
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
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
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
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
".- Implementation Requirements:
- The default implementation is equivalent for this path to:
startsWith(getFileSystem().getPath(other));
- 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
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
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
.- Implementation Requirements:
- The default implementation is equivalent for this path to:
endsWith(getFileSystem().getPath(other));
- Parameters:
other
- the given path string- Returns:
true
if this path ends 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 it is 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 not have a root component and all name elements are redundant
- See Also:
-
resolve
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:
-
resolve
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
".- Implementation Requirements:
- The default implementation is equivalent for this path to:
resolve(getFileSystem().getPath(other));
- 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:
-
resolveSibling
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.- Implementation Requirements:
- The default implementation is equivalent for this path to:
unless(getParent() == null) ? other : getParent().resolve(other);
other == null
, in which case aNullPointerException
is thrown. - Parameters:
other
- the path to resolve against this path's parent- Returns:
- the resulting path
- See Also:
-
resolveSibling
Converts a given path string to aPath
and resolves it against this path'sparent
path in exactly the manner specified by theresolveSibling
method.- Implementation Requirements:
- The default implementation is equivalent for this path to:
resolveSibling(getFileSystem().getPath(other));
- 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:
-
relativize
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 thatPath.of
(
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
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
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
.- Implementation Requirements:
- The default implementation is equivalent for this path to:
if thenew File(toString());
FileSystem
which created thisPath
is the default file system; otherwise anUnsupportedOperationException
is thrown. - 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
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
- Implementation Requirements:
- The default implementation is equivalent for this path to:
register(watcher, events, new WatchEvent.Modifier[0]);
- 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
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.- Specified by:
iterator
in interfaceIterable<Path>
- Implementation Requirements:
- The default implementation returns an
Iterator<Path>
which, for this path, traverses thePath
s returned bygetName(index)
, whereindex
ranges from zero togetNameCount() - 1
, inclusive. - Returns:
- an iterator over the name elements of this path
-
compareTo
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
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. -
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. -
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.
-