gate.persist

Class SerialDataStore

java.lang.Object

gate.util.AbstractFeatureBearer

gate.persist.SerialDataStore

All Implemented Interfaces:

DataStore, FeatureBearer, NameBearer, Serializable

Direct Known Subclasses:

LuceneDataStoreImpl

public class SerialDataStore
extends AbstractFeatureBearer
implements DataStore

A data store based on Java serialisation.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	autoSaving Flag for autosaving behaviour.
protected String	currentProtocolVersion The protocol version of the currently open data store
protected String	name The name of the datastore
protected static String[]	protocolVersionNumbers List of valid protocol version numbers.
protected File	storageDir The directory used for the serialised classes.
protected static String	versionNumber Version number for variations in the storage protocol.

Fields inherited from class gate.util.AbstractFeatureBearer

features

Fields inherited from interface gate.DataStore

DATASTORE_FEATURE_NAME, LR_ID_FEATURE_NAME

Constructor Summary

Constructors

Constructor and Description
SerialDataStore() Default construction.
SerialDataStore(String storageDirUrl) Construction requires a file protocol URL pointing to the storage directory used for the serialised classes.

Method Summary

Modifier and Type	Method and Description
void	addDatastoreListener(DatastoreListener l) Registers a new DatastoreListener with this datastore
LanguageResource	adopt(LanguageResource lr) Adopt a resource for persistence.
boolean	canReadLR(Object lrID) Checks if the user (identified by the sessionID) has read access to the LR
boolean	canWriteLR(Object lrID) Checks if the user (identified by the sessionID) has write access to the LR
void	close() Close the data store.
protected String	constructPersistenceId(String lrName) Create a persistent store Id from the name of a resource.
void	create() Create a new data store.
void	delete() Delete the data store.
void	delete(String lrClassName, Object lrPersistenceId) Delete a resource from the data store.
boolean	equals(Object other) Equality: based on storage dir of other.
protected String[]	filterIgnoredFileNames(String[] fileNames) This removes the names of all files from a list of file names for which we know that we want to ignore them.
List	findLrIds(List constraints) Get a list of LRs that satisfy some set or restrictions
List	findLrIds(List constraints, String lrType) Get a list of LRs that satisfy some set or restrictions and are of a particular type
protected void	fireResourceAdopted(DatastoreEvent e)
protected void	fireResourceDeleted(DatastoreEvent e)
protected void	fireResourceWritten(DatastoreEvent e)
String	getComment() Returns the comment displayed by the GUI for this DataStore
String	getIconName() Returns the name of the icon to be used when this datastore is displayed in the GUI
LanguageResource	getLr(String lrClassName, Object lrPersistenceId) Get a resource from the persistent store.
List<String>	getLrIds(String lrType) Get a list of the IDs of LRs of a particular type that are present.
String	getLrName(Object lrId) Get the name of an LR from its ID.
List<String>	getLrNames(String lrType) Get a list of the names of LRs of a particular type that are present.
List<String>	getLrTypes() Get a list of the types of LR that are present in the data store.
String	getName() Returns the name of this resource
File	getStorageDir() Get method for storage URL
String	getStorageUrl() Get the URL for the underlying storage mechanism.
protected File	getVersionFile() Get a File for the protocol version file.
int	hashCode() Calculate a hash code based on the class and the storage dir.
boolean	isAutoSaving() Get the autosaving behaviour of the LR.
protected static boolean	isValidProtocolVersion(String versionNumber) Check a version number for validity.
boolean	lockLr(LanguageResource lr) Try to acquire exlusive lock on a resource from the persistent store.
void	open() Open a connection to the data store.
protected static int	random() Generate a random integer between 0 and 9999 for file naming.
void	removeDatastoreListener(DatastoreListener l) Removes a a previously registered DatastoreListener from the list listeners for this datastore
void	setAutoSaving(boolean autoSaving) Set method for the autosaving behaviour of the data store.
void	setName(String name) Sets the name of this resource
void	setStorageDir(File storageDir) Set method for storage URL
void	setStorageUrl(String urlString) Set the URL for the underlying storage mechanism.
void	sync(LanguageResource lr) Save: synchonise the in-memory image of the LR with the persistent image.
String	toString() String representation
void	unlockLr(LanguageResource lr) Releases the exlusive lock on a resource from the persistent store.

Methods inherited from class gate.util.AbstractFeatureBearer

getFeatures, setFeatures

Methods inherited from class java.lang.Object

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

Methods inherited from interface gate.util.FeatureBearer

getFeatures, setFeatures

Field Detail

name

protected String name

The name of the datastore

storageDir

protected File storageDir

The directory used for the serialised classes.

currentProtocolVersion

protected String currentProtocolVersion

The protocol version of the currently open data store

versionNumber

protected static final String versionNumber

Version number for variations in the storage protocol. Protocol versions:

• 1.0: uncompressed. Originally had no version file - to read a 1.0 SerialDataStore that has no version file add a version file containing the line "1.0".
• 1.1: has a version file. Uses GZIP compression.

This variable stores the version of the current level of the protocol, NOT the level in use in the currently open data store.

See Also:

Constant Field Values

protocolVersionNumbers

protected static final String[] protocolVersionNumbers

List of valid protocol version numbers.

autoSaving

protected boolean autoSaving

Flag for autosaving behaviour.

Constructor Detail

SerialDataStore

public SerialDataStore(String storageDirUrl)
                throws PersistenceException

Construction requires a file protocol URL pointing to the storage directory used for the serialised classes. NOTE: should not be called except by GATE code.

Throws:

PersistenceException

SerialDataStore

public SerialDataStore()

Default construction. NOTE: should not be called except by GATE code.

Method Detail

setStorageDir

public void setStorageDir(File storageDir)

Set method for storage URL

getStorageDir

public File getStorageDir()

Get method for storage URL

setStorageUrl

public void setStorageUrl(String urlString)
                   throws PersistenceException

Set the URL for the underlying storage mechanism.

Specified by:

setStorageUrl in interface DataStore

Throws:

PersistenceException

getStorageUrl

public String getStorageUrl()

Get the URL for the underlying storage mechanism.

Specified by:

getStorageUrl in interface DataStore

create

public void create()
            throws PersistenceException

Create a new data store. This tries to create a directory in the local file system. If the directory already exists and is non-empty, or is a file, or cannot be created, PersistenceException is thrown.

Specified by:

create in interface DataStore

Throws:

PersistenceException

getVersionFile

protected File getVersionFile()
                       throws IOException

Get a File for the protocol version file.

Throws:

IOException

isValidProtocolVersion

protected static boolean isValidProtocolVersion(String versionNumber)

Check a version number for validity.

delete

public void delete()
            throws PersistenceException

Delete the data store.

Specified by:

delete in interface DataStore

Throws:

PersistenceException

delete

public void delete(String lrClassName,
                   Object lrPersistenceId)
            throws PersistenceException

Delete a resource from the data store.

Specified by:

delete in interface DataStore

Parameters:

lrClassName - class name of the type of resource

lrPersistenceId - a data-store specific unique identifier for the resource

Throws:

PersistenceException

adopt

public LanguageResource adopt(LanguageResource lr)
                       throws PersistenceException

Adopt a resource for persistence.

Specified by:

adopt in interface DataStore

Throws:

PersistenceException

open

public void open()
          throws PersistenceException

Open a connection to the data store.

Specified by:

open in interface DataStore

Throws:

PersistenceException

close

public void close()
           throws PersistenceException

Close the data store.

Specified by:

close in interface DataStore

Throws:

PersistenceException

sync

public void sync(LanguageResource lr)
          throws PersistenceException

Save: synchonise the in-memory image of the LR with the persistent image.

Specified by:

sync in interface DataStore

Throws:

PersistenceException

constructPersistenceId

protected String constructPersistenceId(String lrName)

Create a persistent store Id from the name of a resource.

getLr

public LanguageResource getLr(String lrClassName,
                              Object lrPersistenceId)
                       throws PersistenceException,
                              SecurityException

Description copied from interface: DataStore

Get a resource from the persistent store. You should never call this method directly, instead use the following:

 FeatureMap params = Factory.newFeatureMap();
 params.put(DataStore.DATASTORE_FEATURE_NAME, datastore);
 params.put(DataStore.LR_ID_FEATURE_NAME, lrID);
 LanguageResource lr = (LanguageResource)Factory.createResource(lrClassName, params);

Specified by:

getLr in interface DataStore

Throws:

PersistenceException

SecurityException

getLrTypes

public List<String> getLrTypes()
                        throws PersistenceException

Get a list of the types of LR that are present in the data store.

Specified by:

getLrTypes in interface DataStore

Throws:

PersistenceException

getLrIds

public List<String> getLrIds(String lrType)
                      throws PersistenceException

Get a list of the IDs of LRs of a particular type that are present.

Specified by:

getLrIds in interface DataStore

Throws:

PersistenceException

getLrNames

public List<String> getLrNames(String lrType)
                        throws PersistenceException

Get a list of the names of LRs of a particular type that are present.

Specified by:

getLrNames in interface DataStore

Throws:

PersistenceException

getLrName

public String getLrName(Object lrId)

Get the name of an LR from its ID.

Specified by:

getLrName in interface DataStore

setAutoSaving

public void setAutoSaving(boolean autoSaving)
                   throws UnsupportedOperationException

Set method for the autosaving behaviour of the data store. NOTE: this type of datastore has no auto-save function, therefore this method throws an UnsupportedOperationException.

Specified by:

setAutoSaving in interface DataStore

Throws:

UnsupportedOperationException

isAutoSaving

public boolean isAutoSaving()

Get the autosaving behaviour of the LR.

Specified by:

isAutoSaving in interface DataStore

random

protected static int random()

Generate a random integer between 0 and 9999 for file naming.

toString

public String toString()

String representation

Overrides:

toString in class Object

hashCode

public int hashCode()

Calculate a hash code based on the class and the storage dir.

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Equality: based on storage dir of other.

Overrides:

equals in class Object

removeDatastoreListener

public void removeDatastoreListener(DatastoreListener l)

Description copied from interface: DataStore

Removes a a previously registered DatastoreListener from the list listeners for this datastore

Specified by:

removeDatastoreListener in interface DataStore

addDatastoreListener

public void addDatastoreListener(DatastoreListener l)

Description copied from interface: DataStore

Registers a new DatastoreListener with this datastore

Specified by:

addDatastoreListener in interface DataStore

fireResourceAdopted

protected void fireResourceAdopted(DatastoreEvent e)

fireResourceDeleted

protected void fireResourceDeleted(DatastoreEvent e)

fireResourceWritten

protected void fireResourceWritten(DatastoreEvent e)

getIconName

public String getIconName()

Returns the name of the icon to be used when this datastore is displayed in the GUI

Specified by:

getIconName in interface DataStore

getComment

public String getComment()

Returns the comment displayed by the GUI for this DataStore

Specified by:

getComment in interface DataStore

canReadLR

public boolean canReadLR(Object lrID)
                  throws PersistenceException

Checks if the user (identified by the sessionID) has read access to the LR

Specified by:

canReadLR in interface DataStore

Throws:

PersistenceException

canWriteLR

public boolean canWriteLR(Object lrID)
                   throws PersistenceException

Checks if the user (identified by the sessionID) has write access to the LR

Specified by:

canWriteLR in interface DataStore

Throws:

PersistenceException

setName

public void setName(String name)

Sets the name of this resource

Specified by:

setName in interface NameBearer

getName

public String getName()

Returns the name of this resource

Specified by:

getName in interface NameBearer

lockLr

public boolean lockLr(LanguageResource lr)
               throws PersistenceException,
                      SecurityException

Try to acquire exlusive lock on a resource from the persistent store. Always call unlockLR() when the lock is no longer needed

Specified by:

lockLr in interface DataStore

Throws:

PersistenceException

SecurityException

unlockLr

public void unlockLr(LanguageResource lr)
              throws PersistenceException,
                     SecurityException

Releases the exlusive lock on a resource from the persistent store.

Specified by:

unlockLr in interface DataStore

Throws:

PersistenceException

SecurityException

findLrIds

public List findLrIds(List constraints)
               throws PersistenceException

Get a list of LRs that satisfy some set or restrictions

Specified by:

findLrIds in interface DataStore

Throws:

PersistenceException

findLrIds

public List findLrIds(List constraints,
                      String lrType)
               throws PersistenceException

Get a list of LRs that satisfy some set or restrictions and are of a particular type

Specified by:

findLrIds in interface DataStore

Throws:

PersistenceException

filterIgnoredFileNames

protected String[] filterIgnoredFileNames(String[] fileNames)

This removes the names of all files from a list of file names for which we know that we want to ignore them. Currently, all names starting with a dot are ignored.

Parameters:

fileNames -

Returns:

the list of file names with the ignored names removed