org.archive.util

Class ObjectIdentityBdbManualCache<V extends IdentityCacheable>

java.lang.Object

org.archive.util.ObjectIdentityBdbManualCache<V>

All Implemented Interfaces:

com.google.common.collect.MapEvictionListener<String,V>, Closeable, Serializable, AutoCloseable, ObjectIdentityCache<V>

public class ObjectIdentityBdbManualCache<V extends IdentityCacheable>
extends Object
implements ObjectIdentityCache<V>, Closeable, Serializable, com.google.common.collect.MapEvictionListener<String,V>

A BDB JE backed object cache. Soft references to previously-instantiated objects are held so that unless/until an object is garbage collected, subsequent get()s will return the exact same object (avoiding redundant creation or disagreement about canonical object state).

The backing disk is only guaranteed to be up-to-date after a flush of all dirty values to disk, as can be forced by sync().

Author:

John Erik Halse, stack, gojomo, paul baclace (conversion to ConcurrentMap)

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected AtomicLong	count
protected com.sleepycat.je.Database	db The BDB JE database used for this instance.
protected ConcurrentMap<String,V>	dirtyItems
protected com.sleepycat.collections.StoredSortedMap<String,V>	diskMap The Collection view of the BDB JE database used for this instance.
protected ConcurrentMap<String,V>	memMap in-memory map of new/recent/still-referenced-elsewhere instances

Constructor Summary

Constructors

Constructor and Description
ObjectIdentityBdbManualCache() Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() close/release any associated resources
protected String	composeCacheSummary()
protected com.sleepycat.collections.StoredSortedMap<String,V>	createDiskMap(com.sleepycat.je.Database database, com.sleepycat.bind.serial.StoredClassCatalog classCatalog, Class valueClass)
void	dirtyKey(String key) force the persistent backend, if any, to eventually be updated with live object state for the given key
protected void	finalize()
V	get(String key) get the object under the given key/name -- but should not mutate object state
protected String	getDatabaseName()
V	getOrUse(String key, Supplier<V> supplierOrNull) get the object under the given key/name, using (and remembering) the object supplied by the supplier if no prior mapping exists -- but should not mutate object state
void	initialize(com.sleepycat.je.Environment env, String dbName, Class valueClass, com.sleepycat.bind.serial.StoredClassCatalog classCatalog) Call this method when you have an instance when you used the default constructor or when you have a deserialized instance that you want to reconnect with an extant bdbje environment.
Set<String>	keySet() set of all keys
void	onEviction(String key, V val)
protected com.sleepycat.je.Database	openDatabase(com.sleepycat.je.Environment environment, String dbName)
int	size() count of name-to-object contained
void	sync() Sync all in-memory map entries to backing disk store.

Methods inherited from class java.lang.Object

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

Field Detail

db

protected transient com.sleepycat.je.Database db

The BDB JE database used for this instance.

memMap

protected transient ConcurrentMap<String,V extends IdentityCacheable> memMap

in-memory map of new/recent/still-referenced-elsewhere instances

diskMap

protected transient com.sleepycat.collections.StoredSortedMap<String,V extends IdentityCacheable> diskMap

The Collection view of the BDB JE database used for this instance.

dirtyItems

protected transient ConcurrentMap<String,V extends IdentityCacheable> dirtyItems

count

protected AtomicLong count

Constructor Detail

ObjectIdentityBdbManualCache

public ObjectIdentityBdbManualCache()

Constructor. You must call #initialize(Environment, Class, Class, StoredClassCatalog) to finish construction. Construction is two-stepped to support reconnecting a deserialized CachedBdbMap with its backing bdbje database.

Parameters:

dbName - Name of the backing db this instance should use.

Method Detail

initialize

public void initialize(com.sleepycat.je.Environment env,
              String dbName,
              Class valueClass,
              com.sleepycat.bind.serial.StoredClassCatalog classCatalog)
                throws com.sleepycat.je.DatabaseException

Call this method when you have an instance when you used the default constructor or when you have a deserialized instance that you want to reconnect with an extant bdbje environment. Do not call this method if you used the #CachedBdbMap(File, String, Class, Class) constructor.

Parameters:

env -

keyClass -

valueClass -

classCatalog -

Throws:

com.sleepycat.je.DatabaseException

createDiskMap

protected com.sleepycat.collections.StoredSortedMap<String,V> createDiskMap(com.sleepycat.je.Database database,
                                                                com.sleepycat.bind.serial.StoredClassCatalog classCatalog,
                                                                Class valueClass)

openDatabase

protected com.sleepycat.je.Database openDatabase(com.sleepycat.je.Environment environment,
                                     String dbName)
                                          throws com.sleepycat.je.DatabaseException

Throws:

com.sleepycat.je.DatabaseException

close

public void close()

Description copied from interface: ObjectIdentityCache

close/release any associated resources

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface ObjectIdentityCache<V extends IdentityCacheable>

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable

get

public V get(String key)

Description copied from interface: ObjectIdentityCache

get the object under the given key/name -- but should not mutate object state

Specified by:

get in interface ObjectIdentityCache<V extends IdentityCacheable>

getOrUse

public V getOrUse(String key,
         Supplier<V> supplierOrNull)

Description copied from interface: ObjectIdentityCache

get the object under the given key/name, using (and remembering) the object supplied by the supplier if no prior mapping exists -- but should not mutate object state

Specified by:

getOrUse in interface ObjectIdentityCache<V extends IdentityCacheable>

keySet

public Set<String> keySet()

Description copied from interface: ObjectIdentityCache

set of all keys

Specified by:

keySet in interface ObjectIdentityCache<V extends IdentityCacheable>

composeCacheSummary

protected String composeCacheSummary()

size

public int size()

Description copied from interface: ObjectIdentityCache

count of name-to-object contained

Specified by:

size in interface ObjectIdentityCache<V extends IdentityCacheable>

getDatabaseName

protected String getDatabaseName()

sync

public void sync()

Sync all in-memory map entries to backing disk store.

Specified by:

sync in interface ObjectIdentityCache<V extends IdentityCacheable>

dirtyKey

public void dirtyKey(String key)

Description copied from interface: ObjectIdentityCache

force the persistent backend, if any, to eventually be updated with live object state for the given key

Specified by:

dirtyKey in interface ObjectIdentityCache<V extends IdentityCacheable>

onEviction

public void onEviction(String key,
              V val)

Specified by:

onEviction in interface com.google.common.collect.MapEvictionListener<String,V extends IdentityCacheable>