com.dbxml.db.common.filers
Class MemFiler

java.lang.Object
  com.dbxml.util.SimpleConfigurable
      com.dbxml.db.common.filers.MemFiler

All Implemented Interfaces:

Configurable, Filer

public final class MemFiler

extends SimpleConfigurable

implements Filer

MemFiler is an In-Memory Filer implementation for dbXML. MemFiler can be used for temporary collections and caching. It's basically a layering on top of HashMap.

Constructor Summary

MemFiler()

MemFiler(java.util.Map records)

MemFiler(java.util.Map records, boolean readOnly)

Method Summary

boolean	close() close closes the Filer
boolean	create() create creates a new Filer and any associated resources for the new Filer, such as disk files, etc.
boolean	deleteRecord(Transaction tx, Key key) deleteRecord removes a Record from the Filer based on the specified Key.
boolean	drop() drop instructs the Filerimplementation to remove itself from existence.
boolean	exists() exists returns whether or not a physical representation of this Filer actually exists.
void	flush(Transaction tx) flush forcefully flushes any unwritten buffers to disk.
java.lang.String	getName() getName returns the name of this Filer.
long	getRecordCount(Transaction tx) getRecordCount returns the number of Records in the Filer.
RecordMetaData	getRecordMetaData(Transaction tx, Key key) getRecordMetaData returns metadata about the Record identified by the provided Key.
RecordSet	getRecordSet(Transaction tx) getRecordSet returns a RecordSet object for the current Filer.
TransactionLog	getTransactionLog() getTransactionLog returns the Transaction Log for this Filer.
boolean	isOpened() isOpened returns whether or not the Filer is opened for business.
boolean	open() open opens the Filer
Record	readRecord(Transaction tx, Key key) readRecord returns a Record from the Filer based on the specified Key.
void	setCollection(Collection collection) setCollection tells the Filer who its parent is.
boolean	writeRecord(Transaction tx, Key key, Value value) writeRecord writes a Value to the Filer based on the specified Key.

Methods inherited from class com.dbxml.util.SimpleConfigurable

getConfig, setConfig

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.dbxml.util.Configurable

getConfig, setConfig

Constructor Detail

MemFiler

public MemFiler()

MemFiler

public MemFiler(java.util.Map records,
                boolean readOnly)

MemFiler

public MemFiler(java.util.Map records)

Method Detail

setCollection

public void setCollection(Collection collection)

Description copied from interface: Filer

setCollection tells the Filer who its parent is.

Specified by:

setCollection in interface Filer

Parameters:

collection - The owner Collection

getName

public java.lang.String getName()

Description copied from interface: Filer

getName returns the name of this Filer.

Specified by:

getName in interface Filer

Returns:

the Filer name

create

public boolean create()

Description copied from interface: Filer

create creates a new Filer and any associated resources for the new Filer, such as disk files, etc.

Specified by:

create in interface Filer

Returns:

Whether or not the Filer was created

open

public boolean open()

Description copied from interface: Filer

open opens the Filer

Specified by:

open in interface Filer

Returns:

Whether or not the Filer was opened

isOpened

public boolean isOpened()

Description copied from interface: Filer

isOpened returns whether or not the Filer is opened for business.

Specified by:

isOpened in interface Filer

Returns:

The open status of the Filer

exists

public boolean exists()

Description copied from interface: Filer

exists returns whether or not a physical representation of this Filer actually exists. In the case of a BTreeFiler, this would check for the file, and in the case of an FTPFiler, it might perform a connection check.

Specified by:

exists in interface Filer

Returns:

Whether or not the physical resource exists

drop

public boolean drop()

Description copied from interface: Filer

drop instructs the Filerimplementation to remove itself from existence. The Filer's parent is responsible for removing any references to the Filer in its own context.

Specified by:

drop in interface Filer

Returns:

Whether or not the Filer was dropped

close

public boolean close()

Description copied from interface: Filer

close closes the Filer

Specified by:

close in interface Filer

Returns:

Whether or not the Filer was closed

flush

public void flush(Transaction tx)

Description copied from interface: Filer

flush forcefully flushes any unwritten buffers to disk.

Specified by:

flush in interface Filer

Parameters:

tx - The controlling Transaction

getRecordMetaData

public RecordMetaData getRecordMetaData(Transaction tx,
                                        Key key)
                                 throws DBException

Description copied from interface: Filer

getRecordMetaData returns metadata about the Record identified by the provided Key. This method should make every attempt to not read the actual record from its original location.

Specified by:

getRecordMetaData in interface Filer

Parameters:

tx - The controlling Transaction

key - The Record's Key

Returns:

The Record's metadata

Throws:

DBException

readRecord

public Record readRecord(Transaction tx,
                         Key key)
                  throws DBException

Description copied from interface: Filer

readRecord returns a Record from the Filer based on the specified Key.

Specified by:

readRecord in interface Filer

Parameters:

tx - The controlling Transaction

key - The Record's Key

Returns:

The returned Record

Throws:

DBException

writeRecord

public boolean writeRecord(Transaction tx,
                           Key key,
                           Value value)
                    throws DBException

Description copied from interface: Filer

writeRecord writes a Value to the Filer based on the specified Key.

Specified by:

writeRecord in interface Filer

Parameters:

tx - The controlling Transaction

key - The Record's Key

value - The Record's Value

Returns:

Whether or not the Record could be written

Throws:

DBException

deleteRecord

public boolean deleteRecord(Transaction tx,
                            Key key)
                     throws DBException

Description copied from interface: Filer

deleteRecord removes a Record from the Filer based on the specified Key.

Specified by:

deleteRecord in interface Filer

Parameters:

tx - The controlling Transaction

key - The Record's Key

Returns:

Whether or not the Record was deleted

Throws:

DBException

getRecordCount

public long getRecordCount(Transaction tx)
                    throws DBException

Description copied from interface: Filer

getRecordCount returns the number of Records in the Filer.

Specified by:

getRecordCount in interface Filer

Parameters:

tx - The controlling Transaction

Returns:

The Record count

Throws:

DBException

getRecordSet

public RecordSet getRecordSet(Transaction tx)
                       throws DBException

Description copied from interface: Filer

getRecordSet returns a RecordSet object for the current Filer.

Specified by:

getRecordSet in interface Filer

Parameters:

tx - The controlling Transaction

Returns:

The Filer Enumerator

Throws:

DBException

getTransactionLog

public TransactionLog getTransactionLog()

Description copied from interface: Filer

getTransactionLog returns the Transaction Log for this Filer. This result may be null if the Filer doesn't support transactional operations.

Specified by:

getTransactionLog in interface Filer

Returns:

The Filer's TransactionLog