com.tangosol.persistence

Class AbstractPersistenceManager.AbstractPersistentStore

java.lang.Object

com.tangosol.util.Base

com.tangosol.persistence.AbstractPersistenceManager.AbstractPersistentStore

All Implemented Interfaces:

com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Enclosing class:

AbstractPersistenceManager<PS extends AbstractPersistenceManager.AbstractPersistentStore>

public abstract class AbstractPersistenceManager.AbstractPersistentStore
extends Base
implements com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Abstract implementation of a ReadBuffer-based PersistentStore.

Author:

jh 2012.10.04

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	AbstractPersistenceManager.AbstractPersistentStore.BatchTask Runnable implementation that is used to perform and commit a sequence of mutating persistent store operations asynchronously.
protected class	AbstractPersistenceManager.AbstractPersistentStore.DeleteExtentTask A Task implementation that deletes an extent from the associated store.
protected class	AbstractPersistenceManager.AbstractPersistentStore.OpenTask An OpenTask opens the store (parent of this inner class) with the provided store and notifies the Collector when complete.

Nested classes/interfaces inherited from class com.tangosol.util.Base

Base.LoggingWriter, Base.StackFrame

Nested classes/interfaces inherited from interface com.oracle.coherence.persistence.PersistentStore

com.oracle.coherence.persistence.PersistentStore.Visitor<R>

Field Summary

Fields

Modifier and Type	Field and Description
protected File	f_dirStore The directory used to store persisted data.
protected File	f_fileLock The file used to prevent concurrent access to the data directory underlying this persistent store.
protected ReadWriteLock	f_lock The ReadWriteLock used to protect against concurrent read/write operations.
protected Set<Long>	f_setDeletedIds The set of extent identifiers that are in the process of being deleted.
protected Set<Long>	f_setExtentIds The set of valid extent identifiers known to this persistent store.
protected String	f_sId The identifier of this persistent store.
protected FileLock	m_lockFile The FileLock used to prevent concurrent access to the data directory underlying this persistent store.
protected int	m_nState The state of the PersistenceStore.

Fields inherited from class com.tangosol.util.Base

LOG_ALWAYS, LOG_DEBUG, LOG_ERR, LOG_INFO, LOG_MAX, LOG_MIN, LOG_QUIET, LOG_WARN, POWER_0, POWER_G, POWER_K, POWER_M, POWER_T, UNIT_D, UNIT_H, UNIT_M, UNIT_MS, UNIT_NS, UNIT_S, UNIT_US

Constructor Summary

Constructors

Constructor and Description
AbstractPersistentStore(String sId) Create a new AbstractPersistentStore with the given identifier.

Method Summary

Modifier and Type	Method and Description
void	abort(Object oToken) Abort an atomic sequence of mutating operations.
protected abstract void	abortInternal(Object oToken) Abort an atomic sequence of mutating operations.
Object	begin() Begin a new sequence of mutating operations that should be committed to the store as an atomic unit.
Object	begin(com.oracle.coherence.common.base.Collector<Object> collector, Object oReceipt) Begin a new sequence of mutating operations that should be committed to the store asynchronously as an atomic unit.
protected abstract Object	beginInternal() Begin a sequence of mutating operations that should be committed atomically and return a token that represents the atomic unit.
void	commit(Object oToken) Commit a sequence of mutating operations represented by the given token as an atomic unit.
protected abstract void	commitInternal(Object oToken) Commit a sequence of mutating operations represented by the given token as an atomic unit.
protected void	copyAndOpenInternal(com.oracle.coherence.persistence.PersistentStore<ReadBuffer> storeFrom) Copy the provided store to ensure both the contents are available in the new store and it is open thus ready to receive requests.
protected abstract void	createExtentInternal(long lExtentId) Create the extent with the given identifier in the persistent store.
protected boolean	delete(boolean fSafe) Release any resources held by this persistent store and delete any underlying persistent storage.
void	deleteExtent(long lExtentId) Delete the specified extent from the persistent store, ensuring that any key-value mappings associated with the extent are no longer valid.
protected abstract void	deleteExtentInternal(long lExtentId) Delete the specified extent from the persistent store.
protected abstract boolean	deleteInternal() Remove the underlying persistent storage.
boolean	ensureExtent(long lExtentId) Ensure that an extent with the given identifier exists in the persistent store, returning true iff the extent was created.
protected boolean	ensureExtentInternal(long lExtentId) Ensure the provided extent id has been registered and created, thus allowing subsequent load and store operations against the same extent id.
protected com.oracle.coherence.persistence.PersistenceException	ensurePersistenceException(Throwable eCause) Return a PersistenceException with the given cause.
protected com.oracle.coherence.persistence.PersistenceException	ensurePersistenceException(Throwable eCause, String sMessage) Return a PersistenceException with the given cause and detail message.
protected void	ensureReady() Block the calling thread until the store is either ready to accept requests or the store has been closed.
void	erase(long lExtentId, ReadBuffer bufKey, Object oToken) Remove the specified key from the underlying store if present.
protected abstract void	eraseInternal(long lExtentId, ReadBuffer bufKey, Object oToken) Remove the specified key from the underlying persistent storage if present.
AutoCloseable	exclusively() Suggest to this PersistentStore that the caller requires exclusive access to this store until close is called on the returned AutoCloseable.
long[]	extents() Return a list of the extent identifiers in the underlying store.
File	getDataDirectory() The directory used to store persisted data.
String	getId() Return the identifier of this store.
protected AutoCloseable	instantiateExclusiveClosable() Return an AutoCloseable that will transition this PersistentStore out of exclusive mode.
protected boolean	isClosed() Return true if the store has been closed.
protected boolean	isExclusive() Return true if this store is in exclusive mode.
protected boolean	isReady() Return true if the store is ready to accept requests.
void	iterate(com.oracle.coherence.persistence.PersistentStore.Visitor<ReadBuffer> visitor) Iterate the key-value pairs in the persistent store, applying the specified visitor to each key-value pair.
protected abstract void	iterateInternal(com.oracle.coherence.persistence.PersistentStore.Visitor<ReadBuffer> visitor) Iterate the key-value pairs in the underlying persistent storage, applying the specified visitor to each key-value pair.
ReadBuffer	load(long lExtentId, ReadBuffer bufKey) Return the value associated with the specified key, or null if the key does not have an associated value in the underlying store.
protected abstract void	loadExtentIdsInternal(Set<Long> setIds) Populate the given set with the identifiers of extents in the underlying persistent storage.
protected abstract ReadBuffer	loadInternal(long lExtentId, ReadBuffer bufKey) Load and return the value associated with the specified key from the underlying persistent storage.
protected void	lockRead() Acquire a read lock on this persistent store.
protected boolean	lockStorage() Acquire an exclusive lock on the data directory underlying this persistent store.
protected void	lockWrite() Acquire a write lock on this persistent store.
void	moveExtent(long lOldExtentId, long lNewExtentId) Move the specified extent from the old extent id to the new extent id.
protected void	moveExtentInternal(long lOldExtentId, long lNewExtentId) Move the specified extent from the old extent id to the new extent id.
protected boolean	open(com.oracle.coherence.persistence.PersistentStore<ReadBuffer> storeFrom) Open this persistent store.
protected abstract void	openInternal() Open the underlying persistent storage.
protected void	release() Release any resources held by this persistent store.
protected abstract void	releaseInternal() Release the underlying persistent storage.
protected void	setState(int nState) Set the state of this store.
void	store(long lExtentId, ReadBuffer bufKey, ReadBuffer bufValue, Object oToken) Store the specified value under the specific key in the underlying store.
protected abstract void	storeInternal(long lExtentId, ReadBuffer bufKey, ReadBuffer bufValue, Object oToken) Store the specified value under the specific key in the underlying persistent storage.
protected void	submitOpen(com.oracle.coherence.persistence.PersistentStore<ReadBuffer> storeFrom, com.oracle.coherence.common.base.Collector<Object> collector) Open this store either asynchronously, iff both a store to open from and a collector have been provided, or synchronously.
String	toString() Return a human readable description of this AbstractPersistentStore.
void	truncateExtent(long lExtentId) Truncate the specified extent from the persistent store, ensuring that any key-value mappings associated with the extent are removed.
protected abstract void	truncateExtentInternal(long lExtentId) Truncate the specified extent from the persistent store.
protected void	unlockRead() Release a read lock on this persistent store.
protected void	unlockStorage() Release an exclusive lock on the data directory underlying this persistent store.
protected void	unlockWrite() Release a write lock on this persistent store.
protected void	validateExtentId(long lExtentId) Validate the given extent identifier.
protected void	validateMetadata() Validate the metadata

Methods inherited from class com.tangosol.util.Base

azzert, azzert, azzert, azzertFailed, breakLines, breakLines, capitalize, checkNotEmpty, checkNotNull, checkRange, computeSafeWaitTime, decimalValue, dup, dup, ensureBigDecimal, ensureClassLoader, ensureRuntimeException, ensureRuntimeException, equals, equalsDeep, err, err, err, err, err, escape, formatDateTime, getCallerStackFrame, getCommonMonitor, getCommonMonitor, getCommonMonitor, getContextClassLoader, getContextClassLoader, getDeepMessage, getErr, getLastSafeTimeMillis, getLog, getMaxDecDigits, getMaxHexDigits, getOriginalException, getOut, getProcessRandom, getRandom, getRandomBinary, getRandomBinary, getRandomString, getSafeTimeMillis, getStackFrame, getStackFrames, getStackTrace, getStackTrace, getThreadFactory, getTimeZone, getUpTimeMillis, hashCode, hexValue, indentString, indentString, isDecimal, isHex, isLogEcho, isOctal, log, log, log, log, log, makeInteger, makeLong, makeThread, mod, mod, octalValue, out, out, out, out, out, pad, parseBandwidth, parseBandwidth, parseDelimitedString, parseHex, parseHex, parseMemorySize, parseMemorySize, parsePercentage, parseTime, parseTime, parseTimeNanos, parseTimeNanos, printStackTrace, randomize, randomize, randomize, randomize, read, read, read, read, read, read, read, replace, setErr, setLog, setLogEcho, setOut, sleep, toBandwidthString, toBandwidthString, toCharEscape, toCrc, toCrc, toCrc, toCrc, toCrc, toDecString, toDelimitedString, toDelimitedString, toDelimitedString, toDelimitedString, toHex, toHex, toHexDump, toHexEscape, toHexEscape, toHexEscape, toHexEscape, toHexString, toMemorySizeString, toMemorySizeString, toQuotedCharEscape, toQuotedStringEscape, toSqlString, toString, toString, toStringEscape, toUnicodeEscape, trace, trace, trace, trace, trace, trace, trace, trace, trace, truncateString, truncateString, wait

Methods inherited from class java.lang.Object

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

Field Detail

f_sId

protected final String f_sId

The identifier of this persistent store.

f_dirStore

protected final File f_dirStore

The directory used to store persisted data.

f_fileLock

protected final File f_fileLock

The file used to prevent concurrent access to the data directory underlying this persistent store.

m_nState

protected volatile int m_nState

The state of the PersistenceStore.

m_lockFile

protected FileLock m_lockFile

The FileLock used to prevent concurrent access to the data directory underlying this persistent store.

f_lock

protected final ReadWriteLock f_lock

The ReadWriteLock used to protect against concurrent read/write operations.

f_setExtentIds

protected final Set<Long> f_setExtentIds

The set of valid extent identifiers known to this persistent store.

f_setDeletedIds

protected final Set<Long> f_setDeletedIds

The set of extent identifiers that are in the process of being deleted.

Constructor Detail

AbstractPersistentStore

public AbstractPersistentStore(String sId)

Create a new AbstractPersistentStore with the given identifier.

Parameters:

sId - the identifier for the new store

Throws:

IllegalArgumentException - if the identifier is invalid

Method Detail

getId

public String getId()

Return the identifier of this store.

Specified by:

getId in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Returns:

the identifier that was used to open this store

ensureExtent

public boolean ensureExtent(long lExtentId)

Ensure that an extent with the given identifier exists in the persistent store, returning true iff the extent was created.

Specified by:

ensureExtent in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

lExtentId - the identifier of the extent to ensure

Returns:

true iff the specified extent did not previously exist

deleteExtent

public void deleteExtent(long lExtentId)

Delete the specified extent from the persistent store, ensuring that any key-value mappings associated with the extent are no longer valid.

Removal of the key-value mappings associated with the extent from the underlying storage is the responsibility of the implementation, and may (for example) be performed immediately, asynchronously, or deferred until space is required.

Specified by:

deleteExtent in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

lExtentId - the identifier of the extent to delete

moveExtent

public void moveExtent(long lOldExtentId,
                       long lNewExtentId)

Move the specified extent from the old extent id to the new extent id.

Upon control being returned the implementation guarantees that any data data that used to reside against the old extent id is accessible from new extent id using the load API. In addition, calls to store are permitted immediately after control is returned.

Specified by:

moveExtent in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

lOldExtentId - the old extent identifier

lNewExtentId - the new extent identifier

truncateExtent

public void truncateExtent(long lExtentId)

Truncate the specified extent from the persistent store, ensuring that any key-value mappings associated with the extent are removed.

Removal of the key-value mappings associated with the extent from the underlying storage is the responsibility of the implementation, and may (for example) be performed immediately, asynchronously, or deferred until space is required.

Specified by:

truncateExtent in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

lExtentId - the identifier of the extent to truncate

extents

public long[] extents()

Return a list of the extent identifiers in the underlying store.

Specified by:

extents in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Returns:

a list of the extent identifiers in the underlying store

exclusively

public AutoCloseable exclusively()

Description copied from interface: com.oracle.coherence.persistence.PersistentStore

Suggest to this PersistentStore that the caller requires exclusive access to this store until close is called on the returned AutoCloseable.

Note: the caller must call close on the returned object

Specified by:

exclusively in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Returns:

an AutoCloseable object that requires close to be called on it when exclusive access is no longer needed

load

public ReadBuffer load(long lExtentId,
                       ReadBuffer bufKey)

Return the value associated with the specified key, or null if the key does not have an associated value in the underlying store.

Specified by:

load in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

lExtentId - the extent identifier for the key

bufKey - key whose associated value is to be returned

Returns:

the value associated with the specified key, or null if no value is available for that key

store

public void store(long lExtentId,
                  ReadBuffer bufKey,
                  ReadBuffer bufValue,
                  Object oToken)

Store the specified value under the specific key in the underlying store. This method is intended to support both key-value pair creation and value update for a specific key.

Specified by:

store in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

lExtentId - the extent identifier for the key-value pair

bufKey - key to store the value under

bufValue - value to be stored

oToken - optional token that represents a set of mutating operations to be committed as an atomic unit; if null, the given key-value pair will be committed to the store automatically by this method

erase

public void erase(long lExtentId,
                  ReadBuffer bufKey,
                  Object oToken)

Remove the specified key from the underlying store if present.

Specified by:

erase in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

lExtentId - the extent identifier for the key

bufKey - key whose mapping is to be removed

oToken - optional token that represents a set of mutating operations to be committed as an atomic unit; if null, the removal of the given key will be committed to the store automatically by this method

iterate

public void iterate(com.oracle.coherence.persistence.PersistentStore.Visitor<ReadBuffer> visitor)

Iterate the key-value pairs in the persistent store, applying the specified visitor to each key-value pair.

Specified by:

iterate in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

visitor - the visitor to apply

begin

public Object begin()

Begin a new sequence of mutating operations that should be committed to the store as an atomic unit. The returned token should be passed to all mutating operations that should be part of the atomic unit. Once the sequence of operations have been performed, they must either be committed to the store or the atomic unit must be aborted.

Specified by:

begin in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Returns:

a token that represents the atomic unit

begin

public Object begin(com.oracle.coherence.common.base.Collector<Object> collector,
                    Object oReceipt)

Begin a new sequence of mutating operations that should be committed to the store asynchronously as an atomic unit. The returned token should be passed to all mutating operations that should be part of the atomic unit. Once the sequence of operations have been performed, they must either be committed to the store or the atomic unit must be aborted.

If a collector is passed to this method, the specified receipt will be added to it when the unit is committed. If the operation is aborted or an error occurs during the commit, an AsyncPersistenceException that wraps the cause and specified receipt will be added. Finally, the collector will be flushed.

Specified by:

begin in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

collector - an optional collector

oReceipt - a receipt to be added to the collector (if any) when the unit is committed

Returns:

a token representing the atomic unit that will be committed asynchronously

commit

public void commit(Object oToken)

Commit a sequence of mutating operations represented by the given token as an atomic unit.

Specified by:

commit in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

oToken - a token that represents the atomic unit to commit

abort

public void abort(Object oToken)

Abort an atomic sequence of mutating operations.

Specified by:

abort in interface com.oracle.coherence.persistence.PersistentStore<ReadBuffer>

Parameters:

oToken - a token that represents the atomic unit to abort

submitOpen

protected void submitOpen(com.oracle.coherence.persistence.PersistentStore<ReadBuffer> storeFrom,
                          com.oracle.coherence.common.base.Collector<Object> collector)

Open this store either asynchronously, iff both a store to open from and a collector have been provided, or synchronously.

Parameters:

storeFrom - a PersistentStore to copy from

collector - a collector to notify when the open completes

open

protected boolean open(com.oracle.coherence.persistence.PersistentStore<ReadBuffer> storeFrom)

Open this persistent store.

Parameters:

storeFrom - the PersistenceStore the new store should be based upon

Returns:

true if the store was created

release

protected void release()

Release any resources held by this persistent store.

delete

protected boolean delete(boolean fSafe)

Release any resources held by this persistent store and delete any underlying persistent storage.

Parameters:

fSafe - if true, remove the store by moving it to a restorable location (if possible) rather than deleting it

Returns:

true if the store was successfully deleted, false otherwise

ensureReady

protected void ensureReady()

Block the calling thread until the store is either ready to accept requests or the store has been closed.

Throws:

com.oracle.coherence.persistence.PersistenceException - if the store has been closed or the thread was interrupted

isReady

protected boolean isReady()

Return true if the store is ready to accept requests.

Returns:

true if the store is ready to accept requests

isClosed

protected boolean isClosed()

Return true if the store has been closed.

Returns:

true if the store has been closed

setState

protected void setState(int nState)

Set the state of this store.

Parameters:

nState - the state the store should be transitioned to

isExclusive

protected boolean isExclusive()

Return true if this store is in exclusive mode.

Returns:

true if this store is in exclusive mode

instantiateExclusiveClosable

protected AutoCloseable instantiateExclusiveClosable()

Return an AutoCloseable that will transition this PersistentStore out of exclusive mode.

Returns:

an AutoCloseable that will transition this PersistentStore out of exclusive mode

toString

public String toString()

Return a human readable description of this AbstractPersistentStore.

Overrides:

toString in class Object

Returns:

a human readable description

ensurePersistenceException

protected com.oracle.coherence.persistence.PersistenceException ensurePersistenceException(Throwable eCause)

Return a PersistenceException with the given cause. The returned exception is also initialized with this store, its manager, and its environment (if available).

Parameters:

eCause - an optional cause

Returns:

a PersistenceException with the given cause

ensurePersistenceException

protected com.oracle.coherence.persistence.PersistenceException ensurePersistenceException(Throwable eCause,
                                                                                           String sMessage)

Return a PersistenceException with the given cause and detail message. The returned exception is also initialized with this store, its manager, and its environment (if available).

Parameters:

eCause - an optional cause

sMessage - an optional detail message

Returns:

a PersistenceException with the given cause and detail message

lockStorage

protected final boolean lockStorage()

Acquire an exclusive lock on the data directory underlying this persistent store.

Returns:

true if an exclusive lock was obtained, false otherwise

unlockStorage

protected final void unlockStorage()

Release an exclusive lock on the data directory underlying this persistent store.

lockRead

protected final void lockRead()

Acquire a read lock on this persistent store.

unlockRead

protected final void unlockRead()

Release a read lock on this persistent store.

lockWrite

protected final void lockWrite()

Acquire a write lock on this persistent store.

unlockWrite

protected final void unlockWrite()

Release a write lock on this persistent store.

validateExtentId

protected void validateExtentId(long lExtentId)

Validate the given extent identifier.

Parameters:

lExtentId - the extent identifier

validateMetadata

protected void validateMetadata()

Validate the metadata

ensureExtentInternal

protected boolean ensureExtentInternal(long lExtentId)

Ensure the provided extent id has been registered and created, thus allowing subsequent load and store operations against the same extent id.

Note: the caller is assumed to have exclusive access to this store.

Parameters:

lExtentId - the extent id to register and create

Returns:

true if the extent id was not previously registered and was successfully created

copyAndOpenInternal

protected void copyAndOpenInternal(com.oracle.coherence.persistence.PersistentStore<ReadBuffer> storeFrom)

Copy the provided store to ensure both the contents are available in the new store and it is open thus ready to receive requests.

Note: overriders of this method must guarantee openInternal() is called by either delegating to super or calling it directly.

Parameters:

storeFrom - the store to copy from

openInternal

protected abstract void openInternal()

Open the underlying persistent storage.

Note: this method is guaranteed to only be called by a thread that holds a write lock on this persistent store.

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

releaseInternal

protected abstract void releaseInternal()

Release the underlying persistent storage.

Note: this method is guaranteed to only be called by a thread that holds a write lock on this persistent store.

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

deleteInternal

protected abstract boolean deleteInternal()

Remove the underlying persistent storage.

Note: this method is guaranteed to only be called by a thread that holds a write lock on this persistent store.

Returns:

true on successful removal

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

loadExtentIdsInternal

protected abstract void loadExtentIdsInternal(Set<Long> setIds)

Populate the given set with the identifiers of extents in the underlying persistent storage.

Note: this method is guaranteed to only be called by a thread that holds a write lock on this persistent store.

Parameters:

setIds - a set of ids

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

createExtentInternal

protected abstract void createExtentInternal(long lExtentId)

Create the extent with the given identifier in the persistent store.

Note: this method is guaranteed to only be called by a thread that holds a write lock on this persistent store.

Parameters:

lExtentId - the identifier of the extent to create

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

deleteExtentInternal

protected abstract void deleteExtentInternal(long lExtentId)

Delete the specified extent from the persistent store.

Note: this method is guaranteed to only be called by a thread that holds a write lock on this persistent store.

Parameters:

lExtentId - the identifier of the extent to delete

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

moveExtentInternal

protected void moveExtentInternal(long lOldExtentId,
                                  long lNewExtentId)

Move the specified extent from the old extent id to the new extent id.

Note: this method is guaranteed to only be called by a thread that holds a write lock on this persistent store.

Parameters:

lOldExtentId - the old extent identifier

lNewExtentId - the new extent identifier

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

truncateExtentInternal

protected abstract void truncateExtentInternal(long lExtentId)

Truncate the specified extent from the persistent store.

Note: this method is guaranteed to only be called by a thread that holds a write lock on this persistent store.

Parameters:

lExtentId - the identifier of the extent to truncate

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

loadInternal

protected abstract ReadBuffer loadInternal(long lExtentId,
                                           ReadBuffer bufKey)

Load and return the value associated with the specified key from the underlying persistent storage.

Note: this method is guaranteed to only be called by a thread that holds a read lock on this persistent store.

Parameters:

lExtentId - the extent identifier for the key

bufKey - key whose associated value is to be returned

Returns:

the value associated with the specified key, or null if no value is available for that key

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

storeInternal

protected abstract void storeInternal(long lExtentId,
                                      ReadBuffer bufKey,
                                      ReadBuffer bufValue,
                                      Object oToken)

Store the specified value under the specific key in the underlying persistent storage.

Note: this method is guaranteed to only be called by a thread that holds a read lock on this persistent store.

Parameters:

lExtentId - the extent identifier for the key

bufKey - key to store the value under

bufValue - value to be stored

oToken - a token that represents an atomic unit to commit

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

IllegalArgumentException - if the token is invalid

eraseInternal

protected abstract void eraseInternal(long lExtentId,
                                      ReadBuffer bufKey,
                                      Object oToken)

Remove the specified key from the underlying persistent storage if present.

Note: this method is guaranteed to only be called by a thread that holds a read lock on this persistent store.

Parameters:

lExtentId - the extent identifier for the key

bufKey - key whose mapping is to be removed from the map

oToken - a token that represents an atomic unit to commit

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

IllegalArgumentException - if the token is invalid

iterateInternal

protected abstract void iterateInternal(com.oracle.coherence.persistence.PersistentStore.Visitor<ReadBuffer> visitor)

Iterate the key-value pairs in the underlying persistent storage, applying the specified visitor to each key-value pair.

Note: this method is guaranteed to only be called by a thread that holds a read lock on this persistent store.

Parameters:

visitor - the visitor to apply

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

beginInternal

protected abstract Object beginInternal()

Begin a sequence of mutating operations that should be committed atomically and return a token that represents the atomic unit.

Note: this method is guaranteed to only be called by a thread that holds a read lock on this persistent store.

Returns:

a token that represents the atomic unit to commit

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

commitInternal

protected abstract void commitInternal(Object oToken)

Commit a sequence of mutating operations represented by the given token as an atomic unit.

Note: this method is guaranteed to only be called by a thread that holds a read lock on this persistent store.

Parameters:

oToken - a token that represents the atomic unit to commit

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

IllegalArgumentException - if the token is invalid

abortInternal

protected abstract void abortInternal(Object oToken)

Abort an atomic sequence of mutating operations.

Note: this method is guaranteed to only be called by a thread that holds a read lock on this persistent store.

Parameters:

oToken - a token that represents the atomic unit to abort

Throws:

com.oracle.coherence.persistence.PersistenceException - if a general persistence error occurs

IllegalArgumentException - if the token is invalid

getDataDirectory

public File getDataDirectory()

The directory used to store persisted data.

Returns:

the underlying data storage directory