net.java.truevfs.kernel.spec

Enum FsAccessOption

java.lang.Object

java.lang.Enum<FsAccessOption>

net.java.truevfs.kernel.spec.FsAccessOption

All Implemented Interfaces:

Serializable, Comparable<FsAccessOption>

@Immutable
public enum FsAccessOption
extends Enum<FsAccessOption>

Defines common access options for I/O operations. Not all options may be supported or available for all operations and certain combinations may even be illegal. It's up to the particular operation and file system driver implementation to define which options are supported and available. If an option is not supported, it should get silently ignored. If an option is not available or illegal, an IOException must get thrown.

Author:

Christian Schlichtherle

Enum Constant Summary

Enum Constants

Enum Constant and Description
APPEND Whether or not the contents of an existing file system node shall get kept for appending rather than replaced for overwriting.
CACHE Whether or not the entry data shall get cached for subsequent access.
COMPRESS Expresses a preference to compress an entry within its archive.
CREATE_PARENTS Whether or not any missing parent directory entries shall get created automatically with an undefined last modification time.
ENCRYPT Expresses a preference to encrypt archive entries when writing them to an archive file.
EXCLUSIVE Whether or not a file system node must be exclusively created.
GROW Expresses a preference to allow an archive file to grow by appending any new or updated archive entry contents or meta data to its end.
STORE Expresses a preference to store an entry uncompressed within its archive.

Method Summary

Modifier and Type	Method and Description
static FsAccessOption	valueOf(String name) Returns the enum constant of this type with the specified name.
static FsAccessOption[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

APPEND

public static final FsAccessOption APPEND

Whether or not the contents of an existing file system node shall get kept for appending rather than replaced for overwriting.

CACHE

public static final FsAccessOption CACHE

Whether or not the entry data shall get cached for subsequent access. As a desired side effect, caching allows a federated file system (i.e. prospective archive file) to FsController.sync(net.java.truecommons.shed.BitField<net.java.truevfs.kernel.spec.FsSyncOption>) its contents to its parent file system while some client is still busy on reading or writing the cached entry data.

COMPRESS

public static final FsAccessOption COMPRESS

Expresses a preference to compress an entry within its archive.

Note that this option may get ignored by archive file system drivers. Furthermore, if this happens, there may be no direct feedback available to the caller.

CREATE_PARENTS

public static final FsAccessOption CREATE_PARENTS

Whether or not any missing parent directory entries shall get created automatically with an undefined last modification time.

ENCRYPT

public static final FsAccessOption ENCRYPT

Expresses a preference to encrypt archive entries when writing them to an archive file.

Note that this option may get ignored by archive file system drivers. Furthermore, if this happens, there may be no direct feedback available to the caller.

EXCLUSIVE

public static final FsAccessOption EXCLUSIVE

Whether or not a file system node must be exclusively created.

GROW

public static final FsAccessOption GROW

Expresses a preference to allow an archive file to grow by appending any new or updated archive entry contents or meta data to its end. Setting this option may produce redundant data in the resulting archive file. However, it may yield much better performance if the number and contents of the archive entries to create or update are rather small compared to the total size of the resulting archive file.

This option is the equivalent to a multi-session disc (CD, DVD etc.) for archive files.

Note that this option may get ignored by archive file system drivers. Furthermore, if this happens, there may be no direct feedback available to the caller.

STORE

public static final FsAccessOption STORE

Expresses a preference to store an entry uncompressed within its archive.

Note that this option may get ignored by archive file system drivers. Furthermore, if this happens, there may be no direct feedback available to the caller.

Method Detail

valueOf

public static FsAccessOption valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

values

public static FsAccessOption[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (FsAccessOption c : FsAccessOption.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared