Package Summary  Overview Summary

class:FileStore [NONE]


public abstract class FileStore
extends Object
Storage for files. A 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.

Since:
1.7

constructor:FileStore() [NONE]

  • FileStore

    protected FileStore()
    Initializes a new instance of this class.

method:name() [NONE]

  • name

    public abstract  String name()
    Returns the name of this file store. The format of the name is highly implementation specific. It will typically be the name of the storage pool or volume.

    The string returned by this method may differ from the string returned by the toString method.

    Returns:
    the name of this file store
  • method:type() [NONE]

    type

    public abstract  String type()
    Returns the type of this file store. The format of the string returned by this method is highly implementation specific. It may indicate, for example, the format used or if the file store is local or remote.
    Returns:
    a string representing the type of this file store

    method:isReadOnly() [NONE]

    isReadOnly

    public abstract  boolean isReadOnly()
    Tells whether this file store is read-only. A file store is read-only if it does not support write operations or other changes to files. Any attempt to create a file, open an existing file for writing etc. causes an IOException to be thrown.
    Returns:
    true if, and only if, this file store is read-only

    method:getTotalSpace() [CHANGED]

    getTotalSpace

    public abstract  long getTotalSpace() throws IOException
    Returns the size, in bytes, of the file store. If the total number of bytes in the file store is greater than Long.MAX_VALUE, then Long.MAX_VALUE will be returned.
    Returns:
    the size of the file store, in bytes
    Throws:
    IOException - if an I/O error occurs

    getTotalSpace

    public abstract  long getTotalSpace() throws IOException
    Returns the size, in bytes, of the file store.
    Returns:
    the size of the file store, in bytes
    Throws:
    IOException - if an I/O error occurs

    getTotalSpace

    public abstract  long getTotalSpace() throws IOException
    Returns the size, in bytes, of the file store. If the total number of bytes in the file store is greater than Long.MAX_VALUE, then Long.MAX_VALUE will be returned.
    Returns:
    the size of the file store, in bytes
    Throws:
    IOException - if an I/O error occurs

    method:getUsableSpace() [CHANGED]

    getUsableSpace

    public abstract  long getUsableSpace() throws IOException
    Returns the number of bytes available to this Java virtual machine on the file store. If the number of bytes available is greater than Long.MAX_VALUE, then Long.MAX_VALUE will be returned.

    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.

    Returns:
    the number of bytes available
    Throws:
    IOException - if an I/O error occurs

    getUsableSpace

    public abstract  long getUsableSpace() throws IOException
    Returns the number of bytes available to this Java virtual machine on the file store.

    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.

    Returns:
    the number of bytes available
    Throws:
    IOException - if an I/O error occurs

    getUsableSpace

    public abstract  long getUsableSpace() throws IOException
    Returns the number of bytes available to this Java virtual machine on the file store. If the number of bytes available is greater than Long.MAX_VALUE, then Long.MAX_VALUE will be returned.

    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.

    Returns:
    the number of bytes available
    Throws:
    IOException - if an I/O error occurs

    method:getUnallocatedSpace() [CHANGED]

    getUnallocatedSpace

    public abstract  long getUnallocatedSpace() throws IOException
    Returns the number of unallocated bytes in the file store. If the number of unallocated bytes is greater than Long.MAX_VALUE, then Long.MAX_VALUE will be returned.

    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.

    Returns:
    the number of unallocated bytes
    Throws:
    IOException - if an I/O error occurs

    getUnallocatedSpace

    public abstract  long getUnallocatedSpace() throws IOException
    Returns the number of unallocated bytes in the file store.

    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.

    Returns:
    the number of unallocated bytes
    Throws:
    IOException - if an I/O error occurs

    getUnallocatedSpace

    public abstract  long getUnallocatedSpace() throws IOException
    Returns the number of unallocated bytes in the file store. If the number of unallocated bytes is greater than Long.MAX_VALUE, then Long.MAX_VALUE will be returned.

    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.

    Returns:
    the number of unallocated bytes
    Throws:
    IOException - if an I/O error occurs

    method:getBlockSize() [CHANGED]

    getBlockSize

    public long getBlockSize() throws IOException
    Returns the number of bytes per block in this file store.

    File storage is typically organized into discrete sequences of bytes called blocks. A block is the smallest storage unit of a file store. Every read and write operation is performed on a multiple of blocks.

    Implementation Requirements:
    The implementation in this class throws anUnsupportedOperationException .
    Returns:
    a positive value representing the block size of this file store, in bytes
    Throws:
    IOException - if an I/O error occurs
    UnsupportedOperationException - if the operation is not supported
    Since:
    10

    getBlockSize

    public long getBlockSize() throws IOException
    Returns the number of bytes per block in this file store.

    File storage is typically organized into discrete sequences of bytes called blocks. A block is the smallest storage unit of a file store. Every read and write operation is performed on a multiple of blocks.

    Implementation Requirements:
    The implementation in this class throws an UnsupportedOperationException.
    Returns:
    a positive value representing the block size of this file store, in bytes
    Throws:
    IOException - if an I/O error occurs
    UnsupportedOperationException - if the operation is not supported
    Since:
    10

    getBlockSize

    public long getBlockSize() throws IOException
    Returns the number of bytes per block in this file store.

    File storage is typically organized into discrete sequences of bytes called blocks. A block is the smallest storage unit of a file store. Every read and write operation is performed on a multiple of blocks.

    Implementation Requirements:
    The implementation in this class throws UnsupportedOperationException.
    Returns:
    a positive value representing the block size of this file store, in bytes
    Throws:
    IOException - if an I/O error occurs
    UnsupportedOperationException - if the operation is not supported
    Since:
    10

    method:supportsFileAttributeView(java.lang.Class) [NONE]

    supportsFileAttributeView

    public 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.

    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.

    Parameters:
    type - the file attribute view type
    Returns:
    true if, and only if, the file attribute view is supported

    method:supportsFileAttributeView(java.lang.String) [NONE]

    supportsFileAttributeView

    public abstract  boolean supportsFileAttributeView​(String name)
    Tells whether or not this file store supports the file attributes identified by the given file attribute view.

    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.

    Parameters:
    name - the name of file attribute view
    Returns:
    true if, and only if, the file attribute view is supported

    method:getFileStoreAttributeView(java.lang.Class) [NONE]

    getFileStoreAttributeView

    public abstract  <V extends FileStoreAttributeView> V getFileStoreAttributeView​(Class<V> type)
    Returns a 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.

    Type Parameters:
    V - The FileStoreAttributeView type
    Parameters:
    type - the Class object corresponding to the attribute view
    Returns:
    a file store attribute view of the specified type or null if the attribute view is not available

    method:getAttribute(java.lang.String) [NONE]

    getAttribute

    public abstract  Object getAttribute​(String attribute) throws IOException
    Reads the value of a file store attribute.

    The attribute parameter identifies the attribute to be read and takes the form:

    view-name:attribute-name
    where 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");
     

    Parameters:
    attribute - the attribute to read
    Returns:
    the attribute value; null may be valid for some attributes
    Throws:
    UnsupportedOperationException - if the attribute view is not available or it does not support reading the attribute
    IOException - if an I/O error occurs

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