com.tangosol.util

Class NullImplementation.NullPersistentStore<R>

java.lang.Object

com.tangosol.util.NullImplementation.NullPersistentStore<R>

Type Parameters:

R - the raw value type

All Implemented Interfaces:

com.oracle.datagrid.persistence.PersistentStore<R>

Direct Known Subclasses:

SafePersistenceWrappers.SafePersistentStore

Enclosing class:

NullImplementation

public static class NullImplementation.NullPersistentStore<R>
extends Object
implements com.oracle.datagrid.persistence.PersistentStore<R>

A PersistentStore that does as little as possible.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	NullImplementation.NullPersistentStore.Token Token returned by begin(Collector, Object).

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

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

Field Summary

Fields

Modifier and Type	Field and Description
static NullImplementation.NullPersistentStore	INSTANCE Singleton instance of a NullPersistentStore.

Constructor Summary

Constructors

Constructor and Description
NullPersistentStore()

Method Summary

Modifier and Type	Method and Description
void	abort(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(Collector<Object> collector, Object oReceipt) Begin a new sequence of mutating operations that should be committed to the store asynchronously as an atomic unit.
void	commit(Object oToken) Commit a sequence of mutating operations represented by the given token as an atomic unit.
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the specified extent from the persistent store, ensuring that any key-value mappings associated with the extent are no longer valid.
boolean	ensureExtent(long lExtentId) Ensure that an extent with the given identifier exists in the persistent store, returning true iff the extent was created.
void	erase(long lExtentId, R key, Object oToken) Remove the specified key from the underlying store if present.
long[]	extents() Return a list of the extent identifiers in the underlying store.
String	getId() Return the identifier of this store.
void	iterate(com.oracle.datagrid.persistence.PersistentStore.Visitor<R> visitor) Iterate the key-value pairs in the persistent store, applying the specified visitor to each key-value pair.
R	load(long lExtentId, R key) Return the value associated with the specified key, or null if the key does not have an associated value in the underlying store.
void	store(long lExtentId, R key, R value, Object oToken) Store the specified value under the specific key in the underlying store.
void	truncateExtent(long lExtentId) Truncate the specified extent from the persistent store, ensuring that any key-value mappings associated with the extent are removed.

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final NullImplementation.NullPersistentStore INSTANCE

Singleton instance of a NullPersistentStore.

Constructor Detail

NullPersistentStore

public NullPersistentStore()

Method Detail

getId

public String getId()

Return the identifier of this store.

Specified by:

getId in interface com.oracle.datagrid.persistence.PersistentStore<R>

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.datagrid.persistence.PersistentStore<R>

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.datagrid.persistence.PersistentStore<R>

Parameters:

lExtentId - the identifier of the extent to delete

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.datagrid.persistence.PersistentStore<R>

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.datagrid.persistence.PersistentStore<R>

Returns:

a list of the extent identifiers in the underlying store

load

public R load(long lExtentId,
              R key)

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.datagrid.persistence.PersistentStore<R>

Parameters:

lExtentId - the extent identifier for the key

key - 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,
                  R key,
                  R value,
                  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.datagrid.persistence.PersistentStore<R>

Parameters:

lExtentId - the extent identifier for the key-value pair

key - key to store the value under

value - 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,
                  R key,
                  Object oToken)

Remove the specified key from the underlying store if present.

Specified by:

erase in interface com.oracle.datagrid.persistence.PersistentStore<R>

Parameters:

lExtentId - the extent identifier for the key

key - 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.datagrid.persistence.PersistentStore.Visitor<R> 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.datagrid.persistence.PersistentStore<R>

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.datagrid.persistence.PersistentStore<R>

Returns:

a token that represents the atomic unit

begin

public Object begin(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.datagrid.persistence.PersistentStore<R>

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.datagrid.persistence.PersistentStore<R>

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.datagrid.persistence.PersistentStore<R>

Parameters:

oToken - a token that represents the atomic unit to abort