org.planx.xmlstore.koala.io
Class NodeFileSystemImpl<R extends Locatable>

java.lang.Object
  org.planx.xmlstore.koala.io.NodeFileSystemImpl<R>

All Implemented Interfaces:

FileSystem, Loader<R,SystemNode>, NodeFileSystem<R>

Direct Known Subclasses:

CacheNodeFileSystem, MemoryNodeFileSystem

public class NodeFileSystemImpl<R extends Locatable>
extends Object
implements NodeFileSystem<R>

A NodeFileSystem that decorates an existing FileSystem and associates an IOPolicy.

Author:

Thomas Ambus

Constructor Summary

NodeFileSystemImpl(FileSystem fs, IOPolicy<R> policy)
The NodeFileSystem will use a NodeConverter for converting nodes to and from byte representation.

Method Summary

Bound	all() Returns a locator encapsulating all data currently in this file system.
Bound	allocate() (Optional) Returns a locator to a free write position that can hold an unspecified amount of bytes.
Bound	allocate(long size) Returns a locator to a free write position that can hold size number of bytes.
void	clear() Frees all data in this FileSystem.
void	clearModified() Marks this file system as unmodified.
void	close() Closes this file system and releases all resources.
void	free(Bound l) Frees the space occupied by the specified Bound.
PositionalData	getData(Locator l) Returns a PositionalData for reading and writing to the FileSystem at the specified location.
Bound	getMeta() Returns a locator to a special block of meta data.
IOPolicy<R>	getPolicy() Returns the IOPolicy associated with this NodeFileSystem.
SourceId	id() Returns a SourceId identifying this FileSystem in its present state.
boolean	isContained(Locator l) Returns true if the specified Locator originates from this FileSystem and is valid.
boolean	isModified() Returns true if this file system has been modified since it was created or since the last call to FileSystem.clearModified().
boolean	isReadOnly() Returns true if this file system is read-only.
SystemNode	load(Locator loc, RelativeDualReference<Locator,R> ref) Loads a node from the file system.
SystemNode	load(R ref) Loads a node from the file system.
Locator	save(SystemNode node) Saves at end of the file system by appending (i.e. allocating using allocate()).
void	setMeta(Bound b) Sets the meta data pointer of this file system.
void	setReadOnly(boolean isReadOnly) Sets the read-only status of this file system.
long	size() Returns the size of this file system.
String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

NodeFileSystemImpl

public NodeFileSystemImpl(FileSystem fs,
                          IOPolicy<R> policy)

The NodeFileSystem will use a NodeConverter for converting nodes to and from byte representation.

Method Detail

getPolicy

public IOPolicy<R> getPolicy()

Description copied from interface: NodeFileSystem

Returns the IOPolicy associated with this NodeFileSystem.

Specified by:

getPolicy in interface NodeFileSystem<R extends Locatable>

load

public SystemNode load(R ref)
                throws IOException

Description copied from interface: NodeFileSystem

Loads a node from the file system.

Specified by:

load in interface Loader<R extends Locatable,SystemNode>

Specified by:

load in interface NodeFileSystem<R extends Locatable>

Throws:

IOException

load

public SystemNode load(Locator loc,
                       RelativeDualReference<Locator,R> ref)
                throws IOException

Description copied from interface: NodeFileSystem

Loads a node from the file system.

Specified by:

load in interface NodeFileSystem<R extends Locatable>

Throws:

IOException

save

public Locator save(SystemNode node)
             throws IOException

Saves at end of the file system by appending (i.e. allocating using allocate()).

Specified by:

save in interface NodeFileSystem<R extends Locatable>

Throws:

IOException

id

public SourceId id()
            throws IOException

Description copied from interface: FileSystem

Returns a SourceId identifying this FileSystem in its present state. The SourceId can change at any point and is not necessarily equal to the SourceIds returned by allocation method even though these may still be valid. Thus, this SourceId should be regarded as a unique canonical id that identifies only the present state of this FileSystem.

Specified by:

id in interface FileSystem

Throws:

IOException

allocate

public Bound allocate()
               throws IOException

Description copied from interface: FileSystem

(Optional) Returns a locator to a free write position that can hold an unspecified amount of bytes. Implementations are allowed to throw an UnsupportedOperationException if this is not supported.

Specified by:

allocate in interface FileSystem

Throws:

IOException - if an I/O error occurred.

allocate

public Bound allocate(long size)
               throws IOException

Description copied from interface: FileSystem

Returns a locator to a free write position that can hold size number of bytes.

Specified by:

allocate in interface FileSystem

Throws:

IOException - if an I/O error occurred or the specified amount of bytes could not be allocated.

all

public Bound all()
          throws IOException

Description copied from interface: FileSystem

Returns a locator encapsulating all data currently in this file system.

Specified by:

all in interface FileSystem

Throws:

IOException - if an I/O error occurred.

free

public void free(Bound l)
          throws IOException

Description copied from interface: FileSystem

Frees the space occupied by the specified Bound.

Specified by:

free in interface FileSystem

Throws:

IOException - if an I/O error occurred.

InvalidSourceIdException - if the file system identifier of the locator is invalid.

OutOfBoundsException - if the locator is out of bounds.

getMeta

public Bound getMeta()
              throws IOException

Description copied from interface: FileSystem

Returns a locator to a special block of meta data. Only one meta data block is allowed per file system. If no meta data block has been set, or meta data is not supported, null is returned.

Specified by:

getMeta in interface FileSystem

Throws:

IOException

setMeta

public void setMeta(Bound b)
             throws IOException

Description copied from interface: FileSystem

Sets the meta data pointer of this file system. If meta data is not supported the operation is ignored.

Specified by:

setMeta in interface FileSystem

Throws:

IOException

clear

public void clear()
           throws IOException

Description copied from interface: FileSystem

Frees all data in this FileSystem.

Specified by:

clear in interface FileSystem

Throws:

IOException

getData

public PositionalData getData(Locator l)
                       throws IOException

Description copied from interface: FileSystem

Returns a PositionalData for reading and writing to the FileSystem at the specified location.

Specified by:

getData in interface FileSystem

Throws:

IOException - if an I/O error occurred.

InvalidSourceIdException - if the file system identifier of the locator is invalid.

OutOfBoundsException - if the locator is out of bounds.

size

public long size()
          throws IOException

Description copied from interface: FileSystem

Returns the size of this file system.

Specified by:

size in interface FileSystem

Throws:

IOException - if an I/O error occurred.

isModified

public boolean isModified()
                   throws IOException

Description copied from interface: FileSystem

Returns true if this file system has been modified since it was created or since the last call to FileSystem.clearModified().

Specified by:

isModified in interface FileSystem

Throws:

IOException

clearModified

public void clearModified()
                   throws IOException

Description copied from interface: FileSystem

Marks this file system as unmodified.

Specified by:

clearModified in interface FileSystem

Throws:

IOException

isReadOnly

public boolean isReadOnly()
                   throws IOException

Description copied from interface: FileSystem

Returns true if this file system is read-only.

Specified by:

isReadOnly in interface FileSystem

Throws:

IOException

setReadOnly

public void setReadOnly(boolean isReadOnly)
                 throws IOException

Description copied from interface: FileSystem

Sets the read-only status of this file system.

Specified by:

setReadOnly in interface FileSystem

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: FileSystem

Closes this file system and releases all resources.

Specified by:

close in interface FileSystem

Throws:

IOException - if an I/O error occurred.

isContained

public boolean isContained(Locator l)
                    throws IOException

Description copied from interface: FileSystem

Returns true if the specified Locator originates from this FileSystem and is valid.

Specified by:

isContained in interface FileSystem

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object