public abstract class FileStore extends Object
FileStore
represents a storage pool, device,
partition, volume, concrete file system or other implementation specific means
of file storage. The FileStore
for where a file is stored is obtained
by invoking the getFileStore
method, or all file
stores can be enumerated by invoking the getFileStores
method.
In addition to the methods defined by this class, a file store may support
one or more FileStoreAttributeView
classes
that provide a read-only or updatable view of a set of file store attributes.
Modifier | Constructor and Description |
---|---|
protected |
FileStore()
Initializes a new instance of this class.
|
Modifier and Type | Method and Description |
---|---|
abstract Object |
getAttribute(String attribute)
Reads the value of a file store attribute.
|
abstract <V extends FileStoreAttributeView> |
getFileStoreAttributeView(Class<V> type)
Returns a
FileStoreAttributeView of the given type. |
abstract long |
getTotalSpace()
Returns the size, in bytes, of the file store.
|
abstract long |
getUnallocatedSpace()
Returns the number of unallocated bytes in the file store.
|
abstract long |
getUsableSpace()
Returns the number of bytes available to this Java virtual machine on the
file store.
|
abstract boolean |
isReadOnly()
Tells whether this file store is read-only.
|
abstract String |
name()
Returns the name of this file store.
|
abstract boolean |
supportsFileAttributeView(Class<? extends FileAttributeView> type)
Tells whether or not this file store supports the file attributes
identified by the given file attribute view.
|
abstract boolean |
supportsFileAttributeView(String name)
Tells whether or not this file store supports the file attributes
identified by the given file attribute view.
|
abstract String |
type()
Returns the type of this file store.
|
public abstract String name()
The string returned by this method may differ from the string
returned by the toString
method.
public abstract String type()
public abstract boolean isReadOnly()
IOException
to be thrown.true
if, and only if, this file store is read-onlypublic abstract long getTotalSpace() throws IOException
IOException
- if an I/O error occurspublic abstract long getUsableSpace() throws IOException
The returned number of available bytes is a hint, but not a guarantee, that it is possible to use most or any of these bytes. The number of usable bytes is most likely to be accurate immediately after the space attributes are obtained. It is likely to be made inaccurate by any external I/O operations including those made on the system outside of this Java virtual machine.
IOException
- if an I/O error occurspublic abstract long getUnallocatedSpace() throws IOException
The returned number of unallocated bytes is a hint, but not a guarantee, that it is possible to use most or any of these bytes. The number of unallocated bytes is most likely to be accurate immediately after the space attributes are obtained. It is likely to be made inaccurate by any external I/O operations including those made on the system outside of this virtual machine.
IOException
- if an I/O error occurspublic abstract boolean supportsFileAttributeView(Class<? extends FileAttributeView> type)
Invoking this method to test if the file store supports BasicFileAttributeView
will always return true
. In the case of
the default provider, this method cannot guarantee to give the correct
result when the file store is not a local storage device. The reasons for
this are implementation specific and therefore unspecified.
type
- the file attribute view typetrue
if, and only if, the file attribute view is
supportedpublic abstract boolean supportsFileAttributeView(String name)
Invoking this method to test if the file store supports BasicFileAttributeView
, identified by the name "basic
" will
always return true
. In the case of the default provider, this
method cannot guarantee to give the correct result when the file store is
not a local storage device. The reasons for this are implementation
specific and therefore unspecified.
name
- the name
of file attribute viewtrue
if, and only if, the file attribute view is
supportedpublic abstract <V extends FileStoreAttributeView> V getFileStoreAttributeView(Class<V> type)
FileStoreAttributeView
of the given type.
This method is intended to be used where the file store attribute
view defines type-safe methods to read or update the file store attributes.
The type
parameter is the type of the attribute view required and
the method returns an instance of that type if supported.
V
- The FileStoreAttributeView
typetype
- the Class
object corresponding to the attribute viewnull
if the attribute view is not availablepublic abstract Object getAttribute(String attribute) throws IOException
The attribute
parameter identifies the attribute to be read
and takes the form:
view-name:attribute-namewhere the character
':'
stands for itself.
view-name is the name
of
a AttributeView
that identifies a set of file attributes.
attribute-name is the name of the attribute.
Usage Example: Suppose we want to know if ZFS compression is enabled (assuming the "zfs" view is supported):
boolean compression = (Boolean)fs.getAttribute("zfs:compression");
attribute
- the attribute to readnull
may be a valid valid for some
attributesUnsupportedOperationException
- if the attribute view is not available or it does not support
reading the attributeIOException
- if an I/O error occurs Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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