SK.gnome.dwarf.mail.store
Class GenericFileStore

java.lang.Object
  SK.gnome.dwarf.GenericService
      SK.gnome.dwarf.mail.store.GenericFileStore

All Implemented Interfaces:

SK.gnome.dwarf.Service

Direct Known Subclasses:

FileACLStore, FileMailStore, FileUserStore

public abstract class GenericFileStore

extends SK.gnome.dwarf.GenericService

This class provides a generic filesystem-based store.

This kind of store may be used to hold and manage a user-specific data, like mail messages, security permissions, application configuration files, etc. There is a separate space reserved for each user, represented by a directory in the filesystem.

All user files are kept within the specified userBaseDir directory. For each user ther will be a special subdirectory created in it, with the name equal to the user's name. It may be then obtained via the getUserDirectory(String) method.

If letterSubdirs feature is enabled, the user subdirectories will be grouped according to the first letter of the user name. Thus a user named "joe" would reside in the "<userBaseDir>/j/joe" subdirectory instead of the default "<userBaseDir>/joe". If autoCreate feature is enabled, the getUserDirectory(String) method will automatically create a store for the given user if it does not yet exists.

The storeObject(String, String, Object) and readObject(String, String) methods may be used for reading and storing arbitrary serializable objects to the store. If backupObjects feature is enabled, the storing method will automatically create a backup of the existing file before it stores the serialized object to it. This option is enabled by default.

Field Summary

protected boolean	autoCreate Whether a store will be created automatically for the given user by the getUserDirectory(String) method.
protected boolean	backupObjects Whether a backup file will be create when storing the serialized object by the storeObject(String, String, Object) method.
protected boolean	letterSubdirs Whether a subdirectories will be created according to the first letter of a user identification.
protected java.io.File	userBaseDir The base directory of the store.

Fields inherited from class SK.gnome.dwarf.GenericService

initParameters, parent

Fields inherited from interface SK.gnome.dwarf.Service

INITIALIZED, LOG_DEBUG, LOG_ERROR, LOG_FATAL, LOG_INFO, LOG_TRACE, LOG_WARN, LOG_XFER, SHUTDOWN, STARTED, STOPPED

Constructor Summary

GenericFileStore(java.lang.String name)
Creates a new GenericFileStore.

Method Summary

void	create(java.lang.String user) Creates a store for the given user.
boolean	exists(java.lang.String user) Whether the given user's store exists.
protected java.io.File	getUserDirectory(java.lang.String user) Returns a subdirectory associated with the given user.
void	init(SK.gnome.dwarf.Server parent)
java.lang.String[]	listUsers() Returns a list of all users present in this store.
protected boolean	lock(java.lang.String user, java.lang.String filename) Locks the given file within the user subdirectory.
protected java.lang.Object	readObject(java.lang.String user, java.lang.String filename) Reads an object from the given user store.
void	remove(java.lang.String user) Removes the given user's store.
void	setAutoCreate(boolean enable) Enables or disables the store auto-creation feature.
void	setBackupObjects(boolean enable) Enables or disables backup files when storing the serialized objects.
void	setLetterSubdirs(boolean enable) Enables or disables the first-letter subdirectories.
void	setUserBaseDir(java.io.File dir) Sets the base directory of the store.
protected void	storeObject(java.lang.String user, java.lang.String filename, java.lang.Object object) Stores the object to the given user store.
protected void	unlock(java.lang.String user, java.lang.String filename) Unlocks the given file within the user subdirectory.

Methods inherited from class SK.gnome.dwarf.GenericService

getAuthenticator, getAuthFacility, getFullName, getInitParameter, getInitParameterNames, getLogFacility, getLogger, getName, getParameters, getPrincipal, getShutdownTimeout, getState, log, log, login, logout, setAuthFacility, setInitParameters, setLogFacility, shutdown, start, stop, toString

Methods inherited from class java.lang.Object

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

Field Detail

autoCreate

protected boolean autoCreate

Whether a store will be created automatically for the given user by the getUserDirectory(String) method.

Default value: MailConstants.MAIL_DEFAULT_AUTO_CREATE_STORE

letterSubdirs

protected boolean letterSubdirs

Whether a subdirectories will be created according to the first letter of a user identification.

Default value: false

backupObjects

protected boolean backupObjects

Whether a backup file will be create when storing the serialized object by the storeObject(String, String, Object) method.

Default value: true

userBaseDir

protected java.io.File userBaseDir

The base directory of the store.

Constructor Detail

GenericFileStore

public GenericFileStore(java.lang.String name)

Creates a new GenericFileStore.

Method Detail

setAutoCreate

public void setAutoCreate(boolean enable)

Enables or disables the store auto-creation feature.

Parameters:

enable - true to enable the feature, false to disable

See Also:

autoCreate

setLetterSubdirs

public void setLetterSubdirs(boolean enable)

Enables or disables the first-letter subdirectories.

Parameters:

enable - true to enable the feature, false to disable

See Also:

letterSubdirs

setBackupObjects

public void setBackupObjects(boolean enable)

Enables or disables backup files when storing the serialized objects.

Parameters:

enable - true to enable the feature, false to disable

See Also:

backupObjects

setUserBaseDir

public void setUserBaseDir(java.io.File dir)

Sets the base directory of the store.

Parameters:

dir - the directory

init

public void init(SK.gnome.dwarf.Server parent)
          throws SK.gnome.dwarf.ServiceException

Throws:

SK.gnome.dwarf.ServiceException

create

public void create(java.lang.String user)
            throws MailException

Creates a store for the given user.

Parameters:

user - the user identification

Throws:

MailException - if an error occured

exists

public boolean exists(java.lang.String user)
               throws MailException

Whether the given user's store exists.

Parameters:

user - the user identification

Returns:

true if the store exists, false otherwise

Throws:

MailException - if an error occured

remove

public void remove(java.lang.String user)
            throws MailException

Removes the given user's store.

Parameters:

user - the user identification

Throws:

MailException - if an error occured

listUsers

public java.lang.String[] listUsers()
                             throws MailException

Returns a list of all users present in this store.

Returns:

the array of user identifications

Throws:

MailException - if an error occured

getUserDirectory

protected java.io.File getUserDirectory(java.lang.String user)
                                 throws MailException

Returns a subdirectory associated with the given user.

Parameters:

user - the user identification

Returns:

the user's own subdirectory

Throws:

MailException - if an error occured

readObject

protected java.lang.Object readObject(java.lang.String user,
                                      java.lang.String filename)
                               throws MailException

Reads an object from the given user store.

The returned object is read from a file input stream denoted by the filename argument. If the input file does not exists, a null value is returned.

The object must be stored via the storeObject(String, String, Object) first to be made available for reading.

Parameters:

user - the user identification

filename - the name of file to read the object from

Returns:

the read object or null if the source file does not exists

Throws:

MailException - if an error occured

storeObject

protected void storeObject(java.lang.String user,
                           java.lang.String filename,
                           java.lang.Object object)
                    throws MailException

Stores the object to the given user store.

The object is stored to a file output stream denoted by the filename argument. Only serializable objects may be stored by this method, and only one object instance per file is permitted.

The stored object can be read via the readObject(String, String) method.

Parameters:

user - the user udentification

filename - the name of file to store the object to

object - the object to be stored

Throws:

MailException - if an error occured

lock

protected boolean lock(java.lang.String user,
                       java.lang.String filename)
                throws MailException

Locks the given file within the user subdirectory.

If the filename argument is null, the whole user subdirectory will be locked instead of a single file.

Parameters:

user - the user identification

filename - the name of file

Returns:

true if the file has been locked, false otherwise

Throws:

MailException - if an error occured

unlock

protected void unlock(java.lang.String user,
                      java.lang.String filename)
               throws MailException

Unlocks the given file within the user subdirectory.

If the filename argument is null, the whole user subdirectory will be unlocked instead of a single file.

Parameters:

user - the user identification

filename - the name of file

Throws:

MailException - if an error occured