at.mug.iqm.api.persistence

Class VirtualDataManager

java.lang.Object

at.mug.iqm.api.persistence.VirtualDataManager

public class VirtualDataManager
extends Object

The VirtualDataManager is responsible for holding references to the serialized files where the content is stored.

Instances can query this class in order to obtain the location of an IqmDataBox on the disk, when the application is in virtual state.

This is the central instance when dealing with virtual items. This class uses an instance of Serializer to perform its I/O tasks.

Since:

IQM 3.0

Author:

Philipp Kainz

Field Summary

Fields

Modifier and Type	Field and Description
private HashMap<UUID,File>	boxCache A cache of all serialized items.
private static org.apache.log4j.Logger	logger Custom class logger.
private Serializer	serializer A serializer for I/O tasks of the manager.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	VirtualDataManager() Default constructor.

Method Summary

Modifier and Type	Method and Description
void	clearCache() This method clears the entire virtual box cache.
void	delete(IVirtualizable target) Deletes the virtual object from the disk and removes it from the box cache.
static VirtualDataManager	getInstance()
static File	getNewVirtualDirectory() This method creates a new sub-directory (name) within the temporary directory specified by ConfigManager.getTempPath() of the current ConfigManager instance.
static File	getNewVirtualFileName(File dir, int n) This method gets a new file name with number n.
static File	getRandomVirtualFileName(File dir) This method creates a new temporary file name within the specified directory.
Serializer	getSerializer()
IqmDataBox	load(IVirtualizable target) Load a data item from the serialized state on the hard disk to the memory.
static void	main(String[] args)
IVirtualizable	save(IqmDataBox target, File directory) Save a IVirtualizable object to its specified target and puts the file location to the cache.
List<IqmDataBox>	save(List<IqmDataBox> list, File directory) Saves an entire list of IqmDataBoxes to the temporary directory.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logger

private static final org.apache.log4j.Logger logger

Custom class logger.

serializer

private Serializer serializer

A serializer for I/O tasks of the manager.

boxCache

private HashMap<UUID,File> boxCache

A cache of all serialized items.

Constructor Detail

VirtualDataManager

private VirtualDataManager()

Default constructor.

Method Detail

getSerializer

public Serializer getSerializer()

Returns:

the serializer

getInstance

public static VirtualDataManager getInstance()

Returns:

the current instance

getNewVirtualDirectory

public static File getNewVirtualDirectory()

This method creates a new sub-directory (name) within the temporary directory specified by ConfigManager.getTempPath() of the current ConfigManager instance.
One virtual directory is tied to a specific stack of items in the Tank, holding the serialized objects.

Note that the directory will not yet be created on the hard drive!

Returns:

File the location of the sub-directory

getNewVirtualFileName

public static File getNewVirtualFileName(File dir,
                                         int n)

This method gets a new file name with number n.

Note that the new file will not yet be created on the hard drive!

Parameters:

dir - - the directory

n - - the number to be searched for

Returns:

a new File, containing the name for a IVirtualizable object in a directory

getRandomVirtualFileName

public static File getRandomVirtualFileName(File dir)

This method creates a new temporary file name within the specified directory. A sequential number for individual file naming is automatically created.

Note that the file will not yet be created on the hard drive!

Parameters:

dir - some directory for the virtual file

Returns:

a new temporary file name in the specified directory

save

public IVirtualizable save(IqmDataBox target,
                           File directory)

Save a IVirtualizable object to its specified target and puts the file location to the cache.

Parameters:

target - the target to be saved, e.g. an IqmDataBox

directory - the directory, where the target is being saved (must already exist!)

Returns:

a reference to the virtual item (VirtualDataBox) if successful, or null otherwise

Throws:

IllegalArgumentException - if one of the parameters is null or the directory does not exist

load

public IqmDataBox load(IVirtualizable target)

Load a data item from the serialized state on the hard disk to the memory.

Parameters:

target - the target to be loaded

Returns:

the IqmDataBox containing the data models, or null, if no item is associated with the target

Throws:

IllegalArgumentException - if the parameter is null

delete

public void delete(IVirtualizable target)

Deletes the virtual object from the disk and removes it from the box cache.

Parameters:

target - the object to be deleted

Throws:

IllegalArgumentException - if one of the parameters is null

clearCache

public void clearCache()

This method clears the entire virtual box cache.

CAUTION: Any objects associated with keys in the cache cannot be located afterwards!

save

public List<IqmDataBox> save(List<IqmDataBox> list,
                             File directory)

Saves an entire list of IqmDataBoxes to the temporary directory.

Parameters:

list - the list of boxes to be saved

directory - the directory, where the target is being saved (must already exist!)

Returns:

a reference to the virtual item list if successful, or null otherwise

Throws:

IllegalArgumentException - if one of the parameters is null, the list is empty or the directory does not exist

main

public static void main(String[] args)
                 throws IOException

Throws:

IOException