net.java.truevfs.kernel.spec

Class FsAccessOptionsController

java.lang.Object

net.java.truecommons.shed.UniqueObject

net.java.truevfs.kernel.spec.FsAbstractController

net.java.truevfs.kernel.spec.FsDecoratingController

net.java.truevfs.kernel.spec.FsAccessOptionsController

All Implemented Interfaces:

FsController

public abstract class FsAccessOptionsController
extends FsDecoratingController

Maps the access options before delegating the called operation. The intended use case of this class is for convenient setting or clearing of some file system specific access options with a custom file system driver.

For example, let's assume you would like to use the JAR file format with all entries encrypted according to the WinZip AES specification as your custom application file format. Then you could subclass this class as follows:

class EncryptionController extends FsAccessOptionsController {

    EncryptionController(FsController controller) { super(controller); }

    \@Override
    protected BitField<FsAccessOption> map(BitField<FsAccessOption> options) {
        return options.set(FsAccessOption.ENCRYPT);
    }
}
 

Next, you would have to subclass the JarDriver in order to inject an instance of the EncryptionController as follows:

class EncryptionJarDriver extends JarDriver {
    \@Override
    public FsController decorate(FsController controller) {
        return new EncryptionController(super.decorate(controller));
    }
}
 

Note the call to super.decorate() - this is required to let the super class install the built-in key manager.

Now, whenever you use this driver it would encrypt all entries written to your custom application file format according to the WinZip AES specification.

Mind that this is just sample code - for encryption, you should generally prefer the TrueZIP Driver ZIP.RAES for its increased security level!

Since:

TrueVFS 0.9.2

Author:

Christian Schlichtherle

Nested Class Summary

Nested classes/interfaces inherited from interface net.java.truevfs.kernel.spec.FsController

FsController.Factory<Context>

Field Summary

Fields inherited from class net.java.truevfs.kernel.spec.FsDecoratingController

controller

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	FsAccessOptionsController(FsController controller)

Method Summary

Modifier and Type	Method and Description
void	checkAccess(net.java.truecommons.shed.BitField<FsAccessOption> options, FsNodeName name, net.java.truecommons.shed.BitField<net.java.truecommons.cio.Entry.Access> types) Checks if the file system node for the given name exists when constrained by the given access options and permits the given access types.
net.java.truecommons.cio.InputSocket<? extends net.java.truecommons.cio.Entry>	input(net.java.truecommons.shed.BitField<FsAccessOption> options, FsNodeName name) Returns an input socket for reading the contents of the file system node addressed by the given name from the file system.
void	make(net.java.truecommons.shed.BitField<FsAccessOption> options, FsNodeName name, net.java.truecommons.cio.Entry.Type type, net.java.truecommons.cio.Entry template) Creates or replaces and finally links a chain of one or more entries for the given node name into the file system.
protected abstract net.java.truecommons.shed.BitField<FsAccessOption>	map(net.java.truecommons.shed.BitField<FsAccessOption> options) Maps the given access options.
FsNode	node(net.java.truecommons.shed.BitField<FsAccessOption> options, FsNodeName name) Returns the file system node for the given name or null if it doesn't exist.
net.java.truecommons.cio.OutputSocket<? extends net.java.truecommons.cio.Entry>	output(net.java.truecommons.shed.BitField<FsAccessOption> options, FsNodeName name, net.java.truecommons.cio.Entry template) Returns an output socket for writing the contents of the node addressed by the given name to the file system.
void	setReadOnly(net.java.truecommons.shed.BitField<FsAccessOption> options, FsNodeName name) Sets the named file system node as read-only.
boolean	setTime(net.java.truecommons.shed.BitField<FsAccessOption> options, FsNodeName name, net.java.truecommons.shed.BitField<net.java.truecommons.cio.Entry.Access> types, long value) Makes an attempt to set the last access time of all types in the given bit field for the file system node with the given name.
boolean	setTime(net.java.truecommons.shed.BitField<FsAccessOption> options, FsNodeName name, Map<net.java.truecommons.cio.Entry.Access,Long> times) Makes an attempt to set the last access time of all types in the given map for the file system node with the given name.
void	unlink(net.java.truecommons.shed.BitField<FsAccessOption> options, FsNodeName name) Removes the named file system node from the file system.

Methods inherited from class net.java.truevfs.kernel.spec.FsDecoratingController

getParent, sync, toString

Methods inherited from class net.java.truevfs.kernel.spec.FsAbstractController

getModel, getMountPoint, isMounted, setMounted

Methods inherited from class net.java.truecommons.shed.UniqueObject

equals, hashCode

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

FsAccessOptionsController

protected FsAccessOptionsController(FsController controller)

Method Detail

checkAccess

public final void checkAccess(net.java.truecommons.shed.BitField<FsAccessOption> options,
                              FsNodeName name,
                              net.java.truecommons.shed.BitField<net.java.truecommons.cio.Entry.Access> types)
                       throws IOException

Description copied from interface: FsController

Checks if the file system node for the given name exists when constrained by the given access options and permits the given access types.

Specified by:

checkAccess in interface FsController

Overrides:

checkAccess in class FsDecoratingController

Parameters:

options - the options for accessing the file system node.

name - the name of the file system node.

types - the types of the desired access.

Throws:

IOException - on any I/O error.

input

public final net.java.truecommons.cio.InputSocket<? extends net.java.truecommons.cio.Entry> input(net.java.truecommons.shed.BitField<FsAccessOption> options,
                                                                                                  FsNodeName name)

Description copied from interface: FsController

Returns an input socket for reading the contents of the file system node addressed by the given name from the file system. Note that the assertions for this file system operation equally apply to any channel or stream created by the returned input socket!

Specified by:

input in interface FsController

Overrides:

input in class FsDecoratingController

Parameters:

options - the options for accessing the file system node.

name - the name of the file system node.

Returns:

An InputSocket.

make

public final void make(net.java.truecommons.shed.BitField<FsAccessOption> options,
                       FsNodeName name,
                       net.java.truecommons.cio.Entry.Type type,
                       net.java.truecommons.cio.Entry template)
                throws IOException

Description copied from interface: FsController

Creates or replaces and finally links a chain of one or more entries for the given node name into the file system.

Specified by:

make in interface FsController

Overrides:

make in class FsDecoratingController

Parameters:

options - the options for accessing the file system node. If FsAccessOption.CREATE_PARENTS is set, any missing parent directories shall get created with an undefined last modification time.

name - the name of the file system node.

type - the file system node type.

template - if not null, then the file system node at the end of the chain shall inherit as much properties from this node as possible - with the exception of its name and type.

Throws:

IOException - on any I/O error, including but not limited to these reasons:

• The file system is read only.
• name contains characters which are not supported by the file system.
• The node already exists and either the option FsAccessOption.EXCLUSIVE is set or the node is a directory.
• The node exists as a different type.
• A parent node exists but is not a directory.
• A parent node is missing and createParents is false.

map

protected abstract net.java.truecommons.shed.BitField<FsAccessOption> map(net.java.truecommons.shed.BitField<FsAccessOption> options)

Maps the given access options.

Parameters:

options - the access options to map.

Returns:

The mapped access options.

node

public final FsNode node(net.java.truecommons.shed.BitField<FsAccessOption> options,
                         FsNodeName name)
                  throws IOException

Description copied from interface: FsController

Returns the file system node for the given name or null if it doesn't exist. Modifying the returned node does not show any effect on the file system and should result in an UnsupportedOperationException.

Specified by:

node in interface FsController

Overrides:

node in class FsDecoratingController

Parameters:

options - the options for accessing the file system node.

name - the name of the file system node.

Returns:

A file system node or null if no file system node exists for the given name.

Throws:

IOException - on any I/O error.

output

public final net.java.truecommons.cio.OutputSocket<? extends net.java.truecommons.cio.Entry> output(net.java.truecommons.shed.BitField<FsAccessOption> options,
                                                                                                    FsNodeName name,
                                                                                                    net.java.truecommons.cio.Entry template)

Description copied from interface: FsController

Returns an output socket for writing the contents of the node addressed by the given name to the file system. Note that the assertions for this file system operation equally apply to any channel or stream created by the returned output socket!

Specified by:

output in interface FsController

Overrides:

output in class FsDecoratingController

Parameters:

options - the options for accessing the file system node. If FsAccessOption.CREATE_PARENTS is set, any missing parent directories shall get created with an undefined last modification time.

name - the name of the file system node.

template - if not null, then the file system node at the end of the chain shall inherit as much properties from this node as possible - with the exception of its name and type.

Returns:

An OutputSocket.

setReadOnly

public final void setReadOnly(net.java.truecommons.shed.BitField<FsAccessOption> options,
                              FsNodeName name)
                       throws IOException

Description copied from interface: FsController

Sets the named file system node as read-only. This method will fail for typical archive file system controller implementations because they do not support it.

Specified by:

setReadOnly in interface FsController

Overrides:

setReadOnly in class FsDecoratingController

Parameters:

options - the options for accessing the file system node.

name - the name of the file system node.

Throws:

IOException - on any I/O error or if this operation is not supported.

setTime

public final boolean setTime(net.java.truecommons.shed.BitField<FsAccessOption> options,
                             FsNodeName name,
                             net.java.truecommons.shed.BitField<net.java.truecommons.cio.Entry.Access> types,
                             long value)
                      throws IOException

Description copied from interface: FsController

Makes an attempt to set the last access time of all types in the given bit field for the file system node with the given name. If false is returned or an IOException is thrown, then still some of the last access times may have been set.

Specified by:

setTime in interface FsController

Overrides:

setTime in class FsDecoratingController

Parameters:

options - the options for accessing the file system node.

name - the name of the file system node.

types - the access types.

value - the last access time.

Returns:

true if and only if setting the access time for all types in types succeeded.

Throws:

IOException - on any I/O error.

setTime

public final boolean setTime(net.java.truecommons.shed.BitField<FsAccessOption> options,
                             FsNodeName name,
                             Map<net.java.truecommons.cio.Entry.Access,Long> times)
                      throws IOException

Description copied from interface: FsController

Makes an attempt to set the last access time of all types in the given map for the file system node with the given name. If false is returned or an IOException is thrown, then still some of the last access times may have been set. Whether or not this is an atomic operation is specific to the implementation.

Specified by:

setTime in interface FsController

Overrides:

setTime in class FsDecoratingController

Parameters:

options - the options for accessing the file system node.

name - the name of the file system node.

times - the access times.

Returns:

true if and only if setting the access time for all types in times succeeded.

Throws:

IOException - on any I/O error.

unlink

public final void unlink(net.java.truecommons.shed.BitField<FsAccessOption> options,
                         FsNodeName name)
                  throws IOException

Description copied from interface: FsController

Removes the named file system node from the file system. If the named file system node is a directory, it must be empty.

Specified by:

unlink in interface FsController

Overrides:

unlink in class FsDecoratingController

Parameters:

options - the options for accessing the file system node.

name - the name of the file system node.

Throws:

IOException - on any I/O error.