jpl.mipl.mdms.FileService.komodo.api
Class ClientRestartCache

java.lang.Object
  jpl.mipl.mdms.FileService.komodo.api.ClientRestartCache

public class ClientRestartCache
extends Object

Purpose: Client restart cache JavaBean is used to cache file download and query information. The cached data can be persisted in XML format to assist restarting of user query or file download session. The cache data is stored with file name: <servergroup>.<filetype>.<subtype>.<restart|notify>. It is created per file type.

   Copyright 2005, California Institute of Technology.
   ALL RIGHTS RESERVED.
   U.S. Government Sponsorship acknowledge. 2005.
   

 ============================================================================
 Modification History :
 ----------------------

 Date              Who              What
 ----------------------------------------------------------------------------
 01/01/0001        Thomas           Initial Release
 01/10/2006        Nick             Initial documentation.
 01/10/2006        Nick             Added backup capability.  When committing
                                    a backup of existing file is made.  When
                                    restoring, if cannot restore from file,
                                    the backup is checked.
 ============================================================================
 

Version:

$Id: ClientRestartCache.java,v 1.14 2006/11/01 19:49:56 ntt Exp $

Author:

Thomas Huang (Thomas.Huang@jpl.nasa.gov), Nicholas Toole (Nicholas.T.Toole@jpl.nasa.gov)

Constructor Summary

ClientRestartCache()
Default constructor - required by JavaBean encoding architecture

ClientRestartCache(String servergroup, String filetype, String subtype, Character command, String queryExpression, String cacheFilename)
Constructor

Method Summary

void	addPersist(String filename, long size, long utc) Method to add persist informtion used by resume transfer.
void	addPersist(String filename, String vft, long size, long utc) Method to add persist infomation used by resume transfer on getVFT
static boolean	canRestoreFromCache(String servergroup, String filetype, String subtype, Character command, String classicRegistry, String outputDir) Checks if a cache file associated with the parameters exists.
void	commit() Method to persist this cache JavaBean in XML format.
protected void	commitBackup() Copies existing restart file to a backup version in the name of fault tolerance.
protected void	copyFile(File src, File dst) Copies file using standard Java I/O library.
protected void	copyFileNIO(File src, File dst) Copies file using NIO package.
String	getCacheFilename() Accessor method to return the cache file name
Character	getCommand() Accessor method to return the user command
Hashtable	getFilesToResume() Accessor method to return internal hashtable used to keep track of file resume transfer information
String	getFileType() Accessor method to get file type name
String	getLastQueryExpression() Accessor for last file query expression
String	getLastQueryTime() Accessor to obtain the last query time in CCSDS formated time string
String	getOutputDir() Accessor to file output directory
String	getPersistedCCSDSModTimeString(String filename) Method to return the file modification time in CCSDS formated string
Long	getPersistedFileSize(String filename) Method to obtain the cached file size
Date	getPersistedModTime(String filename) Method to return the file modification time in a Date object
String	getPersistedVFT(String filename) Method to get peristed resume transfer information on a VFT reference
Long	getResumeOffset(String filename) Method to get resume offset value of a file.
String	getServerGroup() Accessor method to return server group name
String	getSubType() Accessor method to file sub-type name
protected void	moveFile(File src, File dst) Renames source file to destination file.
void	removePersist(String filename) Method to remove resume transfer information.
static ClientRestartCache	restoreFromCache(String servergroup, String filetype, String subtype, Character command, String queryExpression, String classicRegistry, String outputDir) Factory method to create a client restart cache.
void	setCacheFilename(String cacheFilename) Method to set the cache file name
void	setCommand(Character command) Method to set the user command operator character
void	setFilesToResume(Hashtable filesToResume) Method to set file resume transfer internal data structure.
void	setFileType(String filetype) Method to set file type name
void	setLastQueryExpression(String lastQueryExpression) Method to set last file query expression
void	setLastQueryTime(long utc) Method to set the last query time in UTC long integer
void	setLastQueryTime(String ccsds) Method to set the last query time in CCSDS-formated time
void	setOutputDir(String outputDir) Method to set the output directory
void	setServerGroup(String servergroup) Method to set server group name
void	setSubType(String subtype) Method to set sub-type name

Methods inherited from class java.lang.Object

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

Constructor Detail

ClientRestartCache

public ClientRestartCache()

Default constructor - required by JavaBean encoding architecture

ClientRestartCache

public ClientRestartCache(String servergroup,
                          String filetype,
                          String subtype,
                          Character command,
                          String queryExpression,
                          String cacheFilename)

Constructor

Parameters:

servergroup - the server group

filetype - the file type

subtype - the file sub-type

command - the user command

queryExpression - the file name query expression

cacheFilename - the cache file name

Method Detail

restoreFromCache

public static ClientRestartCache restoreFromCache(String servergroup,
                                                  String filetype,
                                                  String subtype,
                                                  Character command,
                                                  String queryExpression,
                                                  String classicRegistry,
                                                  String outputDir)

Factory method to create a client restart cache. This method also migrates any existing legacy restart file into the new format

Parameters:

servergroup - server group name

filetype - file tye name

subtype - file sub-type name

command - the command (add,get,list..)

queryExpression - the file name query expression

classicRegistry - the classic registry locaion

outputDir - the file output location. For get or autoget, this should be the output directory where new files will be stored. For show or autoshow, this should be the user cache directory (i.e. $HOME/.komdo)

Returns:

ClientRestartCache built from existing cache file, legacy file, or a new instance

canRestoreFromCache

public static boolean canRestoreFromCache(String servergroup,
                                          String filetype,
                                          String subtype,
                                          Character command,
                                          String classicRegistry,
                                          String outputDir)

Checks if a cache file associated with the parameters exists. First checks for a modern restart file. If that cannot be found, then checks for backup. If not found, finally checks for classic restart file. If none exists, then false is returned.

Parameters:

servergroup - Servergroup name

filetype - Filetype name

subtype - Sub-filetype name

command - Character associated with command

outputDir - Output directory path

outputDir - Output directory path

Returns:

True if a cache file is restorable, false otherwise.

addPersist

public void addPersist(String filename,
                       long size,
                       long utc)

Method to add persist informtion used by resume transfer.

Parameters:

filename - the file name

size - the file size

utc - the file modification time

addPersist

public void addPersist(String filename,
                       String vft,
                       long size,
                       long utc)

Method to add persist infomation used by resume transfer on getVFT

Parameters:

filename - the file name

vft - the reference name registered under a VFT

size - the file size

utc - the file modification time

removePersist

public void removePersist(String filename)

Method to remove resume transfer information. Usually afer a successful transfer

Parameters:

filename - the file name

getPersistedVFT

public String getPersistedVFT(String filename)

Method to get peristed resume transfer information on a VFT reference

Parameters:

filename - the file anme

Returns:

the reference name

getResumeOffset

public Long getResumeOffset(String filename)

Method to get resume offset value of a file. If file is declared in cache, exists and is not dir, then the file length is returned. Otherwise, null is returned.

Parameters:

filename - the file name

Returns:

the offset value, or null

getPersistedFileSize

public Long getPersistedFileSize(String filename)

Method to obtain the cached file size

Parameters:

filename - the file name

Returns:

the file size

getPersistedCCSDSModTimeString

public String getPersistedCCSDSModTimeString(String filename)

Method to return the file modification time in CCSDS formated string

Parameters:

filename - the file name

Returns:

the CCSDS-formated file modification string

getPersistedModTime

public Date getPersistedModTime(String filename)

Method to return the file modification time in a Date object

Parameters:

filename - the file name

Returns:

the Date object

getCacheFilename

public String getCacheFilename()

Accessor method to return the cache file name

Returns:

the cache file name

setCacheFilename

public void setCacheFilename(String cacheFilename)

Method to set the cache file name

Parameters:

cacheFilename - the cache file name

getCommand

public Character getCommand()

Accessor method to return the user command

Returns:

the user command character

setCommand

public void setCommand(Character command)

Method to set the user command operator character

Parameters:

command - the command operator

getServerGroup

public String getServerGroup()

Accessor method to return server group name

Returns:

the server group name

setServerGroup

public void setServerGroup(String servergroup)

Method to set server group name

Parameters:

servergroup - the server group name

getFileType

public String getFileType()

Accessor method to get file type name

Returns:

the file type name

setFileType

public void setFileType(String filetype)

Method to set file type name

Parameters:

filetype - the file type name

getSubType

public String getSubType()

Accessor method to file sub-type name

Returns:

the sub-type name

setSubType

public void setSubType(String subtype)

Method to set sub-type name

Parameters:

subtype - the sub type name

getFilesToResume

public Hashtable getFilesToResume()

Accessor method to return internal hashtable used to keep track of file resume transfer information

Returns:

the hashtable

setFilesToResume

public void setFilesToResume(Hashtable filesToResume)

Method to set file resume transfer internal data structure.

Parameters:

filesToResume - the hashtable

getLastQueryTime

public String getLastQueryTime()

Accessor to obtain the last query time in CCSDS formated time string

Returns:

the last query time

setLastQueryTime

public void setLastQueryTime(long utc)

Method to set the last query time in UTC long integer

Parameters:

utc - the UTC long integer

setLastQueryTime

public void setLastQueryTime(String ccsds)

Method to set the last query time in CCSDS-formated time

Parameters:

ccsds - the CCSDS formated time

getLastQueryExpression

public String getLastQueryExpression()

Accessor for last file query expression

Returns:

the last file query expression

setLastQueryExpression

public void setLastQueryExpression(String lastQueryExpression)

Method to set last file query expression

Parameters:

lastQueryExpression - the last file query expression

getOutputDir

public String getOutputDir()

Accessor to file output directory

Returns:

the output directory

setOutputDir

public void setOutputDir(String outputDir)

Method to set the output directory

Parameters:

outputDir - the output directory

commit

public void commit()
            throws SessionException

Method to persist this cache JavaBean in XML format.

Throws:

SessionException

commitBackup

protected void commitBackup()

Copies existing restart file to a backup version in the name of fault tolerance. When cache is restored from file, it will first check the usual filename. If unsuccessful, it will then check for the backup version, which will be out-of-date, but not as much so as starting over. Finally, if that is unsuccessful, a classic cache file is checked. If all fails, then a cache is created from no persisted state.

moveFile

protected void moveFile(File src,
                        File dst)
                 throws IOException

Renames source file to destination file.

Parameters:

src - Source file

dst - Destination file

Throws:

IOException

copyFile

protected void copyFile(File src,
                        File dst)
                 throws IOException

Copies file using standard Java I/O library.

Parameters:

src - Source file

dst - Destination file

Throws:

IOException

copyFileNIO

protected void copyFileNIO(File src,
                           File dst)
                    throws IOException

Copies file using NIO package.

Parameters:

src - Source file

dst - Destination file

Throws:

IOException