Class FileSystemProvider
- java.lang.Object
-
- java.nio.file.spi.FileSystemProvider
public abstract class FileSystemProvider extends Object
Service-provider class for file systems. The methods defined by the Files
class will typically delegate to an instance of this class.
A file system provider is a concrete implementation of this class that implements the abstract methods defined by this class. A provider is identified by a URI
scheme
. The default provider is identified by the URI scheme "file". It creates the FileSystem
that provides access to the file systems accessible to the Java virtual machine. The FileSystems
class defines how file system providers are located and loaded. The default provider is typically a system-default provider but may be overridden if the system property
java.nio.file.spi.DefaultFileSystemProvider
is set. In that case, the provider has a one argument constructor whose formal parameter type is
FileSystemProvider
. All other providers have a zero argument constructor that initializes the provider.
A provider is a factory for one or more FileSystem
instances. Each file system is identified by a URI
where the URI's scheme matches the provider's scheme
. The default file system, for example, is identified by the URI "file:///"
. A memory-based file system, for example, may be identified by a URI such as "memory:///?name=logfs"
. The newFileSystem
method may be used to create a file system, and the getFileSystem
method may be used to obtain a reference to an existing file system created by the provider. Where a provider is the factory for a single file system then it is provider dependent if the file system is created when the provider is initialized, or later when the newFileSystem
method is invoked. In the case of the default provider, the FileSystem
is created when the provider is initialized.
All of the methods in this class are safe for use by multiple concurrent threads.
- Since:
- 1.7
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | FileSystemProvider() | Initializes a new instance of this class. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
abstract void | checkAccess(Path path,
AccessMode... modes) | Checks the existence, and optionally the accessibility, of a file. |
abstract void | copy(Path source,
Path target,
CopyOption... options) | Copy a file to a target file. |
abstract void | createDirectory(Path dir,
FileAttribute<?>... attrs) | Creates a new directory. |
void | createLink(Path link,
Path existing) | Creates a new link (directory entry) for an existing file. |
void | createSymbolicLink(Path link,
Path target,
FileAttribute<?>... attrs) | Creates a symbolic link to a target. |
abstract void | delete(Path path) | Deletes a file. |
boolean | deleteIfExists(Path path) | Deletes a file if it exists. |
abstract <V extends FileAttributeView> | getFileAttributeView(Path path,
Class<V> type,
LinkOption... options) | Returns a file attribute view of a given type. |
abstract FileStore | getFileStore(Path path) | Returns the |
abstract FileSystem | getFileSystem(URI uri) | Returns an existing |
abstract Path | getPath(URI uri) | Return a |
abstract String | getScheme() | Returns the URI scheme that identifies this provider. |
static List<FileSystemProvider> | installedProviders() | Returns a list of the installed file system providers. |
abstract boolean | isHidden(Path path) | Tells whether or not a file is considered hidden. |
abstract boolean | isSameFile(Path path,
Path path2) | Tests if two paths locate the same file. |
abstract void | move(Path source,
Path target,
CopyOption... options) | Move or rename a file to a target file. |
AsynchronousFileChannel | newAsynchronousFileChannel(Path path,
Set<? extends OpenOption> options,
ExecutorService executor,
FileAttribute<?>... attrs) | Opens or creates a file for reading and/or writing, returning an asynchronous file channel to access the file. |
abstract SeekableByteChannel | newByteChannel(Path path,
Set<? extends OpenOption> options,
FileAttribute<?>... attrs) | Opens or creates a file, returning a seekable byte channel to access the file. |
abstract DirectoryStream<Path> | newDirectoryStream(Path dir,
DirectoryStream.Filter<? super Path> filter) | Opens a directory, returning a |
FileChannel | newFileChannel(Path path,
Set<? extends OpenOption> options,
FileAttribute<?>... attrs) | Opens or creates a file for reading and/or writing, returning a file channel to access the file. |
abstract FileSystem | newFileSystem(URI uri,
Map<String,?> env) | Constructs a new |
FileSystem | newFileSystem(Path path,
Map<String,?> env) | Constructs a new |
InputStream | newInputStream(Path path,
OpenOption... options) | Opens a file, returning an input stream to read from the file. |
OutputStream | newOutputStream(Path path,
OpenOption... options) | Opens or creates a file, returning an output stream that may be used to write bytes to the file. |
abstract <A extends BasicFileAttributes> | readAttributes(Path path,
Class<A> type,
LinkOption... options) | Reads a file's attributes as a bulk operation. |
abstract Map<String,Object> | readAttributes(Path path,
String attributes,
LinkOption... options) | Reads a set of file attributes as a bulk operation. |
Path | readSymbolicLink(Path link) | Reads the target of a symbolic link. |
abstract void | setAttribute(Path path,
String attribute,
Object value,
LinkOption... options) | Sets the value of a file attribute. |
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
FileSystemProvider
protected FileSystemProvider()
Initializes a new instance of this class.
During construction a provider may safely access files associated with the default provider but care needs to be taken to avoid circular loading of other installed providers. If circular loading of installed providers is detected then an unspecified error is thrown.
- Throws:
-
SecurityException
- If a security manager has been installed and it deniesRuntimePermission
("fileSystemProvider")
Method Detail
installedProviders
public static List<FileSystemProvider> installedProviders()
Returns a list of the installed file system providers.
The first invocation of this method causes the default provider to be initialized (if not already initialized) and loads any other installed providers as described by the FileSystems
class.
- Returns:
- An unmodifiable list of the installed file system providers. The list contains at least one element, that is the default file system provider
- Throws:
-
ServiceConfigurationError
- When an error occurs while loading a service provider
getScheme
public abstract String getScheme()
Returns the URI scheme that identifies this provider.
- Returns:
- The URI scheme
newFileSystem
public abstract FileSystem newFileSystem(URI uri, Map<String,?> env) throws IOException
Constructs a new FileSystem
object identified by a URI. This method is invoked by the FileSystems.newFileSystem(URI,Map)
method to open a new file system identified by a URI.
The uri
parameter is an absolute, hierarchical URI, with a scheme equal (without regard to case) to the scheme supported by this provider. The exact form of the URI is highly provider dependent. The env
parameter is a map of provider specific properties to configure the file system.
This method throws FileSystemAlreadyExistsException
if the file system already exists because it was previously created by an invocation of this method. Once a file system is closed
it is provider-dependent if the provider allows a new file system to be created with the same URI as a file system it previously created.
- Parameters:
-
uri
- URI reference -
env
- A map of provider specific properties to configure the file system; may be empty - Returns:
- A new file system
- Throws:
-
IllegalArgumentException
- If the pre-conditions for theuri
parameter aren't met, or theenv
parameter does not contain properties required by the provider, or a property value is invalid -
IOException
- An I/O error occurs creating the file system -
SecurityException
- If a security manager is installed and it denies an unspecified permission required by the file system provider implementation -
FileSystemAlreadyExistsException
- If the file system has already been created
getFileSystem
public abstract FileSystem getFileSystem(URI uri)
Returns an existing FileSystem
created by this provider.
This method returns a reference to a FileSystem
that was created by invoking the newFileSystem(URI,Map)
method. File systems created the newFileSystem(Path,Map)
method are not returned by this method. The file system is identified by its URI
. Its exact form is highly provider dependent. In the case of the default provider the URI's path component is "/"
and the authority, query and fragment components are undefined (Undefined components are represented by null
).
Once a file system created by this provider is closed
it is provider-dependent if this method returns a reference to the closed file system or throws FileSystemNotFoundException
. If the provider allows a new file system to be created with the same URI as a file system it previously created then this method throws the exception if invoked after the file system is closed (and before a new instance is created by the newFileSystem
method).
If a security manager is installed then a provider implementation may require to check a permission before returning a reference to an existing file system. In the case of the default
file system, no permission check is required.
- Parameters:
-
uri
- URI reference - Returns:
- The file system
- Throws:
-
IllegalArgumentException
- If the pre-conditions for theuri
parameter aren't met -
FileSystemNotFoundException
- If the file system does not exist -
SecurityException
- If a security manager is installed and it denies an unspecified permission.
getPath
public abstract Path getPath(URI uri)
Return a Path
object by converting the given URI
. The resulting Path
is associated with a FileSystem
that already exists or is constructed automatically.
The exact form of the URI is file system provider dependent. In the case of the default provider, the URI scheme is "file"
and the given URI has a non-empty path component, and undefined query, and fragment components. The resulting Path
is associated with the default default
FileSystem
.
If a security manager is installed then a provider implementation may require to check a permission. In the case of the default
file system, no permission check is required.
- Parameters:
-
uri
- The URI to convert - Returns:
- The resulting
Path
- Throws:
-
IllegalArgumentException
- If the URI scheme does not identify this provider or other preconditions on the uri parameter do not hold -
FileSystemNotFoundException
- The file system, identified by the URI, does not exist and cannot be created automatically -
SecurityException
- If a security manager is installed and it denies an unspecified permission.
newFileSystem
public FileSystem newFileSystem(Path path, Map<String,?> env) throws IOException
Constructs a new FileSystem
to access the contents of a file as a file system.
This method is intended for specialized providers of pseudo file systems where the contents of one or more files is treated as a file system. The env
parameter is a map of provider specific properties to configure the file system.
If this provider does not support the creation of such file systems or if the provider does not recognize the file type of the given file then it throws UnsupportedOperationException
. The default implementation of this method throws UnsupportedOperationException
.
- Parameters:
-
path
- The path to the file -
env
- A map of provider specific properties to configure the file system; may be empty - Returns:
- A new file system
- Throws:
-
UnsupportedOperationException
- If this provider does not support access to the contents as a file system or it does not recognize the file type of the given file -
IllegalArgumentException
- If theenv
parameter does not contain properties required by the provider, or a property value is invalid -
IOException
- If an I/O error occurs -
SecurityException
- If a security manager is installed and it denies an unspecified permission.
newInputStream
public InputStream newInputStream(Path path, OpenOption... options) throws IOException
Opens a file, returning an input stream to read from the file. This method works in exactly the manner specified by the Files.newInputStream(java.nio.file.Path, java.nio.file.OpenOption...)
method.
The default implementation of this method opens a channel to the file as if by invoking the newByteChannel(java.nio.file.Path, java.util.Set<? extends java.nio.file.OpenOption>, java.nio.file.attribute.FileAttribute<?>...)
method and constructs a stream that reads bytes from the channel. This method should be overridden where appropriate.
- Parameters:
-
path
- the path to the file to open -
options
- options specifying how the file is opened - Returns:
- a new input stream
- Throws:
-
IllegalArgumentException
- if an invalid combination of options is specified -
UnsupportedOperationException
- if an unsupported option is specified -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.
newOutputStream
public OutputStream newOutputStream(Path path, OpenOption... options) throws IOException
Opens or creates a file, returning an output stream that may be used to write bytes to the file. This method works in exactly the manner specified by the Files.newOutputStream(java.nio.file.Path, java.nio.file.OpenOption...)
method.
The default implementation of this method opens a channel to the file as if by invoking the newByteChannel(java.nio.file.Path, java.util.Set<? extends java.nio.file.OpenOption>, java.nio.file.attribute.FileAttribute<?>...)
method and constructs a stream that writes bytes to the channel. This method should be overridden where appropriate.
- Parameters:
-
path
- the path to the file to open or create -
options
- options specifying how the file is opened - Returns:
- a new output stream
- Throws:
-
IllegalArgumentException
- ifoptions
contains an invalid combination of options -
UnsupportedOperationException
- if an unsupported option is specified -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the file. ThecheckDelete
method is invoked to check delete access if the file is opened with theDELETE_ON_CLOSE
option.
newFileChannel
public FileChannel newFileChannel(Path path, Set<? extends OpenOption> options, FileAttribute<?>... attrs) throws IOException
Opens or creates a file for reading and/or writing, returning a file channel to access the file. This method works in exactly the manner specified by the FileChannel.open
method. A provider that does not support all the features required to construct a file channel throws
UnsupportedOperationException
. The default provider is required to support the creation of file channels. When not overridden, the default implementation throws UnsupportedOperationException
.
- Parameters:
-
path
- the path of the file to open or create -
options
- options specifying how the file is opened -
attrs
- an optional list of file attributes to set atomically when creating the file - Returns:
- a new file channel
- Throws:
-
IllegalArgumentException
- If the set contains an invalid combination of options -
UnsupportedOperationException
- If this provider that does not support creating file channels, or an unsupported open option or file attribute is specified -
IOException
- If an I/O error occurs -
SecurityException
- In the case of the default file system, theSecurityManager.checkRead(String)
method is invoked to check read access if the file is opened for reading. TheSecurityManager.checkWrite(String)
method is invoked to check write access if the file is opened for writing
newAsynchronousFileChannel
public AsynchronousFileChannel newAsynchronousFileChannel(Path path, Set<? extends OpenOption> options, ExecutorService executor, FileAttribute<?>... attrs) throws IOException
Opens or creates a file for reading and/or writing, returning an asynchronous file channel to access the file. This method works in exactly the manner specified by the AsynchronousFileChannel.open
method. A provider that does not support all the features required to construct an asynchronous file channel throws UnsupportedOperationException
. The default provider is required to support the creation of asynchronous file channels. When not overridden, the default implementation of this method throws UnsupportedOperationException
.
- Parameters:
-
path
- the path of the file to open or create -
options
- options specifying how the file is opened -
executor
- the thread pool ornull
to associate the channel with the default thread pool -
attrs
- an optional list of file attributes to set atomically when creating the file - Returns:
- a new asynchronous file channel
- Throws:
-
IllegalArgumentException
- If the set contains an invalid combination of options -
UnsupportedOperationException
- If this provider that does not support creating asynchronous file channels, or an unsupported open option or file attribute is specified -
IOException
- If an I/O error occurs -
SecurityException
- In the case of the default file system, theSecurityManager.checkRead(String)
method is invoked to check read access if the file is opened for reading. TheSecurityManager.checkWrite(String)
method is invoked to check write access if the file is opened for writing
newByteChannel
public abstract SeekableByteChannel newByteChannel(Path path, Set<? extends OpenOption> options, FileAttribute<?>... attrs) throws IOException
Opens or creates a file, returning a seekable byte channel to access the file. This method works in exactly the manner specified by the Files.newByteChannel(Path,Set,FileAttribute[])
method.
- Parameters:
-
path
- the path to the file to open or create -
options
- options specifying how the file is opened -
attrs
- an optional list of file attributes to set atomically when creating the file - Returns:
- a new seekable byte channel
- Throws:
-
IllegalArgumentException
- if the set contains an invalid combination of options -
UnsupportedOperationException
- if an unsupported open option is specified or the array contains attributes that cannot be set atomically when creating the file -
FileAlreadyExistsException
- if a file of that name already exists and theCREATE_NEW
option is specified (optional specific exception) -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the path if the file is opened for reading. ThecheckWrite
method is invoked to check write access to the path if the file is opened for writing. ThecheckDelete
method is invoked to check delete access if the file is opened with theDELETE_ON_CLOSE
option.
newDirectoryStream
public abstract DirectoryStream<Path> newDirectoryStream(Path dir, DirectoryStream.Filter<? super Path> filter) throws IOException
Opens a directory, returning a DirectoryStream
to iterate over the entries in the directory. This method works in exactly the manner specified by the Files.newDirectoryStream(java.nio.file.Path, java.nio.file.DirectoryStream.Filter)
method.
- Parameters:
-
dir
- the path to the directory -
filter
- the directory stream filter - Returns:
- a new and open
DirectoryStream
object - Throws:
-
NotDirectoryException
- if the file could not otherwise be opened because it is not a directory (optional specific exception) -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the directory.
createDirectory
public abstract void createDirectory(Path dir, FileAttribute<?>... attrs) throws IOException
Creates a new directory. This method works in exactly the manner specified by the Files.createDirectory(java.nio.file.Path, java.nio.file.attribute.FileAttribute<?>...)
method.
- Parameters:
-
dir
- the directory to create -
attrs
- an optional list of file attributes to set atomically when creating the directory - Throws:
-
UnsupportedOperationException
- if the array contains an attribute that cannot be set atomically when creating the directory -
FileAlreadyExistsException
- if a directory could not otherwise be created because a file of that name already exists (optional specific exception) -
IOException
- if an I/O error occurs or the parent directory does not exist -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the new directory.
createSymbolicLink
public void createSymbolicLink(Path link, Path target, FileAttribute<?>... attrs) throws IOException
Creates a symbolic link to a target. This method works in exactly the manner specified by the Files.createSymbolicLink(java.nio.file.Path, java.nio.file.Path, java.nio.file.attribute.FileAttribute<?>...)
method.
The default implementation of this method throws
UnsupportedOperationException
.
- Parameters:
-
link
- the path of the symbolic link to create -
target
- the target of the symbolic link -
attrs
- the array of attributes to set atomically when creating the symbolic link - Throws:
-
UnsupportedOperationException
- if the implementation does not support symbolic links or the array contains an attribute that cannot be set atomically when creating the symbolic link -
FileAlreadyExistsException
- if a file with the name already exists (optional specific exception) -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, it deniesLinkPermission
("symbolic")
or itscheckWrite
method denies write access to the path of the symbolic link.
createLink
public void createLink(Path link, Path existing) throws IOException
Creates a new link (directory entry) for an existing file. This method works in exactly the manner specified by the Files.createLink(java.nio.file.Path, java.nio.file.Path)
method.
The default implementation of this method throws
UnsupportedOperationException
.
- Parameters:
-
link
- the link (directory entry) to create -
existing
- a path to an existing file - Throws:
-
UnsupportedOperationException
- if the implementation does not support adding an existing file to a directory -
FileAlreadyExistsException
- if the entry could not otherwise be created because a file of that name already exists (optional specific exception) -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, it deniesLinkPermission
("hard")
or itscheckWrite
method denies write access to either the link or the existing file.
delete
public abstract void delete(Path path) throws IOException
Deletes a file. This method works in exactly the manner specified by the Files.delete(java.nio.file.Path)
method.
- Parameters:
-
path
- the path to the file to delete - Throws:
-
NoSuchFileException
- if the file does not exist (optional specific exception) -
DirectoryNotEmptyException
- if the file is a directory and could not otherwise be deleted because the directory is not empty (optional specific exception) -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, theSecurityManager.checkDelete(String)
method is invoked to check delete access to the file
deleteIfExists
public boolean deleteIfExists(Path path) throws IOException
Deletes a file if it exists. This method works in exactly the manner specified by the Files.deleteIfExists(java.nio.file.Path)
method.
The default implementation of this method simply invokes delete(java.nio.file.Path)
ignoring the NoSuchFileException
when the file does not exist. It may be overridden where appropriate.
- Parameters:
-
path
- the path to the file to delete - Returns:
-
true
if the file was deleted by this method;false
if the file could not be deleted because it did not exist - Throws:
-
DirectoryNotEmptyException
- if the file is a directory and could not otherwise be deleted because the directory is not empty (optional specific exception) -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, theSecurityManager.checkDelete(String)
method is invoked to check delete access to the file
readSymbolicLink
public Path readSymbolicLink(Path link) throws IOException
Reads the target of a symbolic link. This method works in exactly the manner specified by the Files.readSymbolicLink(java.nio.file.Path)
method.
The default implementation of this method throws
UnsupportedOperationException
.
- Parameters:
-
link
- the path to the symbolic link - Returns:
- The target of the symbolic link
- Throws:
-
UnsupportedOperationException
- if the implementation does not support symbolic links -
NotLinkException
- if the target could otherwise not be read because the file is not a symbolic link (optional specific exception) -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, it checks thatFilePermission
has been granted with the "readlink
" action to read the link.
copy
public abstract void copy(Path source, Path target, CopyOption... options) throws IOException
Copy a file to a target file. This method works in exactly the manner specified by the Files.copy(Path,Path,CopyOption[])
method except that both the source and target paths must be associated with this provider.
- Parameters:
-
source
- the path to the file to copy -
target
- the path to the target file -
options
- options specifying how the copy should be done - Throws:
-
UnsupportedOperationException
- if the array contains a copy option that is not supported -
FileAlreadyExistsException
- if the target file exists but cannot be replaced because theREPLACE_EXISTING
option is not specified (optional specific exception) -
DirectoryNotEmptyException
- theREPLACE_EXISTING
option is specified but the file cannot be replaced because it is a non-empty directory (optional specific exception) -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the source file, thecheckWrite
is invoked to check write access to the target file. If a symbolic link is copied the security manager is invoked to checkLinkPermission
("symbolic")
.
move
public abstract void move(Path source, Path target, CopyOption... options) throws IOException
Move or rename a file to a target file. This method works in exactly the manner specified by the Files.move(java.nio.file.Path, java.nio.file.Path, java.nio.file.CopyOption...)
method except that both the source and target paths must be associated with this provider.
- Parameters:
-
source
- the path to the file to move -
target
- the path to the target file -
options
- options specifying how the move should be done - Throws:
-
UnsupportedOperationException
- if the array contains a copy option that is not supported -
FileAlreadyExistsException
- if the target file exists but cannot be replaced because theREPLACE_EXISTING
option is not specified (optional specific exception) -
DirectoryNotEmptyException
- theREPLACE_EXISTING
option is specified but the file cannot be replaced because it is a non-empty directory (optional specific exception) -
AtomicMoveNotSupportedException
- if the options array contains theATOMIC_MOVE
option but the file cannot be moved as an atomic file system operation. -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to both the source and target file.
isSameFile
public abstract boolean isSameFile(Path path, Path path2) throws IOException
Tests if two paths locate the same file. This method works in exactly the manner specified by the Files.isSameFile(java.nio.file.Path, java.nio.file.Path)
method.
- Parameters:
-
path
- one path to the file -
path2
- the other path - Returns:
-
true
if, and only if, the two paths locate the same file - Throws:
-
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to both files.
isHidden
public abstract boolean isHidden(Path path) throws IOException
Tells whether or not a file is considered hidden. This method works in exactly the manner specified by the Files.isHidden(java.nio.file.Path)
method.
This method is invoked by the isHidden
method.
- Parameters:
-
path
- the path to the file to test - Returns:
-
true
if the file is considered hidden - Throws:
-
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.
getFileStore
public abstract FileStore getFileStore(Path path) throws IOException
Returns the FileStore
representing the file store where a file is located. This method works in exactly the manner specified by the Files.getFileStore(java.nio.file.Path)
method.
- Parameters:
-
path
- the path to the file - Returns:
- the file store where the file is stored
- Throws:
-
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file, and in addition it checksRuntimePermission
("getFileStoreAttributes")
checkAccess
public abstract void checkAccess(Path path, AccessMode... modes) throws IOException
Checks the existence, and optionally the accessibility, of a file.
This method may be used by the isReadable
, isWritable
and isExecutable
methods to check the accessibility of a file.
This method checks the existence of a file and that this Java virtual machine has appropriate privileges that would allow it access the file according to all of access modes specified in the modes
parameter as follows:
Value | Description |
---|---|
READ | Checks that the file exists and that the Java virtual machine has permission to read the file. |
WRITE | Checks that the file exists and that the Java virtual machine has permission to write to the file, |
EXECUTE | Checks that the file exists and that the Java virtual machine has permission to execute the file. The semantics may differ when checking access to a directory. For example, on UNIX systems, checking for EXECUTE access checks that the Java virtual machine has permission to search the directory in order to access file or subdirectories. |
If the modes
parameter is of length zero, then the existence of the file is checked.
This method follows symbolic links if the file referenced by this object is a symbolic link. Depending on the implementation, this method may require to read file permissions, access control lists, or other file attributes in order to check the effective access to the file. To determine the effective access to a file may require access to several attributes and so in some implementations this method may not be atomic with respect to other file system operations.
- Parameters:
-
path
- the path to the file to check -
modes
- The access modes to check; may have zero elements - Throws:
-
UnsupportedOperationException
- an implementation is required to support checking forREAD
,WRITE
, andEXECUTE
access. This exception is specified to allow for theAccess
enum to be extended in future releases. -
NoSuchFileException
- if a file does not exist (optional specific exception) -
AccessDeniedException
- the requested access would be denied or the access cannot be determined because the Java virtual machine has insufficient privileges or other reasons. (optional specific exception) -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
is invoked when checking read access to the file or only the existence of the file, thecheckWrite
is invoked when checking write access to the file, andcheckExec
is invoked when checking execute access.
getFileAttributeView
public abstract <V extends FileAttributeView> V getFileAttributeView(Path path, Class<V> type, LinkOption... options)
Returns a file attribute view of a given type. This method works in exactly the manner specified by the Files.getFileAttributeView(java.nio.file.Path, java.lang.Class<V>, java.nio.file.LinkOption...)
method.
- Type Parameters:
-
V
- TheFileAttributeView
type - Parameters:
-
path
- the path to the file -
type
- theClass
object corresponding to the file attribute view -
options
- options indicating how symbolic links are handled - Returns:
- a file attribute view of the specified type, or
null
if the attribute view type is not available
readAttributes
public abstract <A extends BasicFileAttributes> A readAttributes(Path path, Class<A> type, LinkOption... options) throws IOException
Reads a file's attributes as a bulk operation. This method works in exactly the manner specified by the Files.readAttributes(Path,Class,LinkOption[])
method.
- Type Parameters:
-
A
- TheBasicFileAttributes
type - Parameters:
-
path
- the path to the file -
type
- theClass
of the file attributes required to read -
options
- options indicating how symbolic links are handled - Returns:
- the file attributes
- Throws:
-
UnsupportedOperationException
- if an attributes of the given type are not supported -
IOException
- if an I/O error occurs -
SecurityException
- In the case of the default provider, a security manager is installed, itscheckRead
method is invoked to check read access to the file
readAttributes
public abstract Map<String,Object> readAttributes(Path path, String attributes, LinkOption... options) throws IOException
Reads a set of file attributes as a bulk operation. This method works in exactly the manner specified by the Files.readAttributes(Path,String,LinkOption[])
method.
- Parameters:
-
path
- the path to the file -
attributes
- the attributes to read -
options
- options indicating how symbolic links are handled - Returns:
- a map of the attributes returned; may be empty. The map's keys are the attribute names, its values are the attribute values
- Throws:
-
UnsupportedOperationException
- if the attribute view is not available -
IllegalArgumentException
- if no attributes are specified or an unrecognized attributes is specified -
IOException
- If an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, itscheckRead
method denies read access to the file. If this method is invoked to read security sensitive attributes then the security manager may be invoke to check for additional permissions.
setAttribute
public abstract void setAttribute(Path path, String attribute, Object value, LinkOption... options) throws IOException
Sets the value of a file attribute. This method works in exactly the manner specified by the Files.setAttribute(java.nio.file.Path, java.lang.String, java.lang.Object, java.nio.file.LinkOption...)
method.
- Parameters:
-
path
- the path to the file -
attribute
- the attribute to set -
value
- the attribute value -
options
- options indicating how symbolic links are handled - Throws:
-
UnsupportedOperationException
- if the attribute view is not available -
IllegalArgumentException
- if the attribute name is not specified, or is not recognized, or the attribute value is of the correct type but has an inappropriate value -
ClassCastException
- If the attribute value is not of the expected type or is a collection containing elements that are not of the expected type -
IOException
- If an I/O error occurs -
SecurityException
- In the case of the default provider, and a security manager is installed, itscheckWrite
method denies write access to the file. If this method is invoked to set security sensitive attributes then the security manager may be invoked to check for additional permissions.