com.bigdata.journal

Class TemporaryRawStore

java.lang.Object

com.bigdata.rawstore.AbstractRawStore

com.bigdata.rawstore.AbstractRawWormStore

com.bigdata.journal.TemporaryRawStore

All Implemented Interfaces:

ICounterSetAccess, IAddressManager, IMRMW, IMROW, IRawStore, IStreamStore, IWORM

Direct Known Subclasses:

TemporaryStore

public class TemporaryRawStore
extends AbstractRawWormStore
implements IMRMW

A non-restart-safe store for temporary data that buffers data in memory until the write cache overflows (or is flushed to the disk) and then converts to a disk-based store. The backing file (if any) is released when the temporary store is close()d.

Author:

Bryan Thompson

See Also:

BufferMode.Temporary, DiskOnlyStrategy

Field Summary

Fields inherited from class com.bigdata.rawstore.AbstractRawWormStore

am

Fields inherited from interface com.bigdata.rawstore.IAddressManager

NULL

Constructor Summary

Constructors

Constructor and Description
TemporaryRawStore() Create a TemporaryRawStore.
TemporaryRawStore(int offsetBits) Create a TemporaryRawStore.
TemporaryRawStore(long maximumExtent, int offsetBits, File file) Create a TemporaryRawStore with the specified configuration.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	assertOpen()
void	close() Close the store and delete the associated file, if any.
void	delete(long addr) The default implementation is a NOP.
void	deleteResources() Note: This operation is a NOP since close() always deletes the backing file and deleteResources() requires that the store is closed as a pre-condition.
void	destroy() Simply delegates to close() since close() always deletes the backing file for a temporary store.
protected void	finalize() Closes the store if it gets GCd.
void	force(boolean metadata) Force the data to stable storage.
DiskOnlyStrategy	getBufferStrategy()
CounterSet	getCounters() Return performance counters.
File	getFile() The backing file -or- null if there is no backing file for the store.
int	getMaxRecordSize() The maximum length of a record that may be written on the store.
IResourceMetadata	getResourceMetadata() Note: Temporary stores do not have persistent resource descriptions.
protected static File	getTempFile() Return an empty File created using the temporary file name mechanism.
static File	getTempFile(File tmpDir) Return an empty File created using the temporary file name mechanism in the specified directory.
UUID	getUUID() The UUID of this TemporaryRawStore.
boolean	isFullyBuffered() Return false since the temporary store is (at least in principle) backed by disk.
boolean	isOpen() true iff the store is open.
boolean	isReadOnly() true iff the store does not allow writes.
boolean	isStable() Always returns false since the store will be deleted as soon as it is closed.
ByteBuffer	read(long addr) Read the data (unisolated).
long	size() The #of application data bytes written on the store (does not count any headers or root blocks that may exist for the store).
String	toString()
long	write(ByteBuffer data) Write the data (unisolated).

Methods inherited from class com.bigdata.rawstore.AbstractRawWormStore

getAddressManager, getByteCount, getOffset, getOffsetBits, getPhysicalAddress, toAddr, toString

Methods inherited from class com.bigdata.rawstore.AbstractRawStore

getInputStream, getOutputStream

Methods inherited from class java.lang.Object

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

Constructor Detail

TemporaryRawStore

public TemporaryRawStore()

Create a TemporaryRawStore.

TemporaryRawStore

public TemporaryRawStore(int offsetBits)

Create a TemporaryRawStore.

Parameters:

offsetBits - This determines the capacity of the store file and the maximum length of a record. The value is passed through to WormAddressManager.WormAddressManager(int).

TemporaryRawStore

public TemporaryRawStore(long maximumExtent,
                 int offsetBits,
                 File file)

Create a TemporaryRawStore with the specified configuration.

Parameters:

maximumExtent - The maximum extent allowed for the TemporaryRawStore -or- ZERO (0L) iff no limit should be imposed.

offsetBits - This determines the capacity of the store file and the maximum length of a record. The value is passed through to WormAddressManager.WormAddressManager(int).

file - The name of the backing file. The file will be created on demand if it does not exist. It will be an error if the file exists and has a non-zero size at that time. The file will be registered with the JVM for for "delete on exit" and will be deleted regardless as soon as the store is closed.

Method Detail

getTempFile

protected static File getTempFile()

Return an empty File created using the temporary file name mechanism. The file name will begin with bigdata and end with .tmp. The file is marked for eventual deletion.

getTempFile

public static File getTempFile(File tmpDir)

Return an empty File created using the temporary file name mechanism in the specified directory. The directory will be created if it does not exist and the caller has sufficient permissions. The file name will begin with bigdata and end with .tmp. The file is marked for eventual deletion.

Parameters:

tmpDir - The directory within which to create the temporary file.

getUUID

public final UUID getUUID()

The UUID of this TemporaryRawStore. This is reported as part of getResourceMetadata() and may also be used to ensure that ILocatableResources created on a TemporaryStore are placed within a unique namespace.

Specified by:

getUUID in interface IRawStore

finalize

protected void finalize()
                 throws Throwable

Closes the store if it gets GCd.

Overrides:

finalize in class Object

Throws:

Throwable

toString

public String toString()

Overrides:

toString in class Object

getFile

public final File getFile()

Description copied from interface: IRawStore

The backing file -or- null if there is no backing file for the store.

Specified by:

getFile in interface IRawStore

close

public void close()

Close the store and delete the associated file, if any.

Specified by:

close in interface IRawStore

deleteResources

public void deleteResources()

Note: This operation is a NOP since close() always deletes the backing file and deleteResources() requires that the store is closed as a pre-condition.

Specified by:

deleteResources in interface IRawStore

getResourceMetadata

public final IResourceMetadata getResourceMetadata()

Note: Temporary stores do not have persistent resource descriptions.

Specified by:

getResourceMetadata in interface IRawStore

getBufferStrategy

public final DiskOnlyStrategy getBufferStrategy()

destroy

public final void destroy()

Simply delegates to close() since close() always deletes the backing file for a temporary store.

Specified by:

destroy in interface IRawStore

See Also:

IRawStore.deleteResources()

force

public final void force(boolean metadata)

Description copied from interface: IRawStore

Force the data to stable storage. While this is NOT sufficient to guarantee an atomic commit, the data must be forced to disk as part of an atomic commit protocol.

Specified by:

force in interface IRawStore

Parameters:

metadata - If true, then force both the file contents and the file metadata to disk.

size

public final long size()

Description copied from interface: IRawStore

The #of application data bytes written on the store (does not count any headers or root blocks that may exist for the store).

Specified by:

size in interface IRawStore

assertOpen

protected final void assertOpen()

isOpen

public final boolean isOpen()

Description copied from interface: IRawStore

true iff the store is open.

Specified by:

isOpen in interface IRawStore

Returns:

true iff the store is open.

isReadOnly

public final boolean isReadOnly()

Description copied from interface: IRawStore

true iff the store does not allow writes.

Specified by:

isReadOnly in interface IRawStore

isStable

public final boolean isStable()

Always returns false since the store will be deleted as soon as it is closed.

Specified by:

isStable in interface IRawStore

isFullyBuffered

public final boolean isFullyBuffered()

Return false since the temporary store is (at least in principle) backed by disk.

Specified by:

isFullyBuffered in interface IRawStore

read

public final ByteBuffer read(long addr)

Description copied from interface: IRawStore

Read the data (unisolated).

Specified by:

read in interface IRawStore

Parameters:

addr - A long integer that encodes both the offset from which the data will be read and the #of bytes to be read. See IAddressManager.toAddr(int, long).

Returns:

The data read. The buffer will be flipped to prepare for reading (the position will be zero and the limit will be the #of bytes read).

write

public final long write(ByteBuffer data)

Description copied from interface: IRawStore

Write the data (unisolated).

Specified by:

write in interface IRawStore

Parameters:

data - The data. The bytes from the current Buffer.position() to the Buffer.limit() will be written and the Buffer.position() will be advanced to the Buffer.limit() . The caller may subsequently modify the contents of the buffer without changing the state of the store (i.e., the data are copied into the store).

Returns:

A long integer formed that encodes both the offset from which the data may be read and the #of bytes to be read. See IAddressManager.

getMaxRecordSize

public final int getMaxRecordSize()

The maximum length of a record that may be written on the store.

getCounters

public CounterSet getCounters()

Description copied from interface: ICounterSetAccess

Return performance counters.

Specified by:

getCounters in interface ICounterSetAccess

delete

public void delete(long addr)

Description copied from class: AbstractRawStore

The default implementation is a NOP.

Specified by:

delete in interface IRawStore

Overrides:

delete in class AbstractRawStore

Parameters:

addr - A long integer formed using Addr that encodes both the offset at which the data was written and the #of bytes that were written.