de.ipcon.db.core

Class CachingBOLoader

java.lang.Object

de.ipcon.db.core.BOLoaderWrapper

de.ipcon.db.core.CachingBOLoader

All Implemented Interfaces:

BLOBLoaderI, BOLoaderI, BOLoaderWithCacheI, BOQueryLoaderI, SaveBOListenerI, DBManEventListenerI, GrooqlBOLoaderI, SchemaProviderI, java.io.Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

CachingBOLoaderDuringGC, CachingBOLoaderExtended

public class CachingBOLoader
extends BOLoaderWrapper
implements BOLoaderWithCacheI, SaveBOListenerI, DBManEventListenerI, java.io.Closeable

A BOLoader that is caching and supports updating of (at least some) cached values defined by a strategy and garbage collection of unused or old entries.

Nested Class Summary

Nested classes/interfaces inherited from interface de.ipcon.db.core.BOQueryLoaderI

BOQueryLoaderI.InternalHelper

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	bpQuery The query used to load the procs when merging changes

Fields inherited from interface de.ipcon.db.core.BOLoaderI

rootPaneToLockOnConnectionInterrupt

Constructor Summary

Constructors

Constructor and Description
CachingBOLoader(BOLoaderI _realBOLoader)
CachingBOLoader(BOLoaderI _realBOLoader, CachingBOLoaderGCStrategyI _gcStrategy, CachingBOLoaderUpdateStrategyI _updateStrategy)
CachingBOLoader(BOLoaderI _realBOLoader, java.lang.Class[] _keepClasses, int[] _maxKeeps) Creates a caching bo loader with a default LRU strategy to limit the number of certain classes inside the cache.
CachingBOLoader(BOLoaderI _realBOLoader, java.lang.Class[] _keepClasses, int[] _maxKeeps, int _interval)

Method Summary

Modifier and Type	Method and Description
void	addBOCacheListener(BOCacheListenerI l) Registers a BOCacheListenerI on this Object that is notified of any BO changes
static BO[]	assureInstrumentedSchema(BO[] _bos)
void	close() Closes the 'cache', dropping all cached values, stopping any update and gc collection threads.
BO	coerceBOLoader(BO bo)
void	drain() If this BOLoader has a cache, we request it to empty it.
BO	frapBO(BO bo) Coerces the BO Loader of the provided BO to this BOLoaderI on cache miss or returns the cached instance
void	frapEntries(java.util.Map mapForReplacingFrappedValues, java.util.Iterator entriesIterator, boolean cloneOnFrap, java.util.Map<java.lang.Long,BO> tempCache) Calls the 'frapBO' method on all map entries in the given iterator and potentially updates the values in the map the iterator is based on.
BO	frapFromCache(BO bo) Either returns the cached version for this BO or creates a deepcloned copy with this as BOLoader
void	gc(java.util.Iterator rootsIt) Remove any BOs inside the cache that aren't reachable from any BO returned by the Iterator
void	gc(java.util.Map root) Remove any BOs inside the cache that aren't reachable from the provided root-BOs.
BO	getBO(java.lang.Long id) wrapper for getBO(id, null).
BO	getBO(java.lang.Long id, java.lang.Class<? extends BOI> classtip) Returns the BO with the given id.
BO[]	getBOs(java.lang.Long[] ids) wrapper for getBOs(ids, null)
BO[]	getBOs(java.lang.Long[] ids, java.lang.Class<? extends BOI> classtip) returns the BOs with the given ids.
BOT	getBOT(java.lang.Class<? extends BOI> clazz)
int	getDrainCount()
static CachingBOLoader	getInstrumentedInstance(BOLoaderI _bol) Creates a CachingBOLoader instance with an instrumented schema which allows to dynamically add new virtual attributes.
java.util.Collection<BO>	getKnown(java.lang.Class<? extends BOI> clazz)
BO	getKnown(java.lang.Long id)
java.lang.String	getMiniDesc(BO bo)
SchemaI	getSchema() gets a reference to the schema which is used by this BOLoader.
boolean	isCaching() If true, then this BOLoaderI uses an internal cache, holding all BOs hat were loaded or frapped into it.
boolean	isKnown(java.lang.Long id) returns true, if the passed Class is one of the keepClasses or a subclass of them
void	processDBManEvent(DBManEvent e) Invoked when a subscribed DBManEvent occurs.
void	removeBOCacheListener(BOCacheListenerI l) Removes a previously registered BOCacheListenerI again
void	replayProc(BOProc p, java.util.Map<java.lang.Long,BO> affected) Replays the provided BOProc on the cached object and adds the updated BO to the affected Map
void	rescheduleGC(int interval) Starts or stops a daemon, that clears the cache every interval seconds, but keeps a maximum number of instances of objects of types keepClasses specified in maxKeeps.
void	setGCStrategy(CachingBOLoaderGCStrategyI _gcStrategy) Stops a possibly running AutoGC on the old gcStrategy and replaces it with this instance.
void	setRealBOLoader(BOLoaderI _realBOLoader) Sets the BOLoader to handle any cache misses with.
void	setUpdateStrategy(CachingBOLoaderUpdateStrategyI _updateStrategy)
void	stopAutoGC() Stops the daemon thread that automatically runs, if any.
void	subscribeForUpdatesViaEvents() Register for BOChangeEvents so we can call replayProc for the relevant BPs which affect the keepClasses or their subclasses.
void	transactionSaveSuccess(Transaction stubTx, java.util.function.Predicate<Transaction> isSavedTransactionInstancePredicate) Callback through which this SaveBOListenerI is notified about a successfully saved Transaction.
void	unsubscribeForUpdatesViaEvents() Unsubscribes from any update registration, effectively letting objects in the cache go stale.
void	updateCache(BP bp, java.util.Map<java.lang.Long,BO> affected, CachingBOLoaderUpdateStrategyI myUpdateStrategy) Checks the given BP against the current cache state and merges it if it appears to be needed in the cache.
void	updateCache(DBManBOChangeEvent boce) Does the actual merge and replay of a BO Change event.
void	updateStrategies(CachingBOLoaderGCStrategyI _gcStrategy, CachingBOLoaderUpdateStrategyI _updateStrategy) Replaces the current update and gc strategy with the provided ones.

Methods inherited from class de.ipcon.db.core.BOLoaderWrapper

coerceBOLoader, coerceBOLoader, coerceBOLoader, coerceBOLoader, execute, exists, exists, getBLOB, getBLOB, getBLOB, getBLOB, getBLOB, getBLOB, getBLOB, getBLOB, getBLOBInfo, getBLOBInfo, getBOs, getBOs, getBOUncached, getBOUncached, getCryptoHandler, getEventProvider, getFeatureManager, getFileVault, getNextId, getParentLoader, getRelationBOs, getRootLoader, getRootPaneToLockOnConnectionInterrupt, hasBLOB, hasBLOB, haveBLOB, isLoggedIn, isLoggedInNN, isRecording, prepareQuery, prepareQuery, query, query, query, queryBO, queryBO, queryBO, queryRelation, setRootPaneToLockOnConnectionInterrupt, testAuth, testAuth

Methods inherited from class java.lang.Object

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

Methods inherited from interface de.ipcon.db.core.BOLoaderWithCacheI

isKnown

Methods inherited from interface de.ipcon.db.core.BOLoaderI

execute, exists, exists, frapBOArrayFromCache, frapBOIArrayFromCache, frapBOsFromCache, frapFromCache, getBOs, getBOs, getBOUncached, getBOUncached, getCryptoHandler, getEventProvider, getFeatureManager, getFileVault, getNextId, getParentLoader, getRelationBOs, getRootLoader, isAncestorOf, isLoggedIn, isLoggedInNN, isRecording, isRootLoader, isServerSide, isTesting, prepareQuery, prepareQuery, prepareQuery, query, query, query, queryBO, queryBO, queryBO, queryRelation, testAuth, testAuth

Methods inherited from interface de.ipcon.db.blob.BLOBLoaderI

getBLOB, getBLOB, getBLOB, getBLOB, getBLOB, getBLOB, getBLOB, getBLOB, getBLOBInfo, getBLOBInfo, hasBLOB, hasBLOB, haveBLOB, haveBLOB, haveBLOB

Methods inherited from interface de.ipcon.db.core.BOQueryLoaderI

getBOByAttr, getBOByAttr, getBOByAttr, getBOByAttrs, getBOByAttrs, getBOByAttrs, getBOsByAttrs, getBOsByAttrs, getBOsByAttrs, getBOsByAttrs, getOneBOByAttr, getUniqueBOByAttr

Field Detail

bpQuery

public static final java.lang.String bpQuery

The query used to load the procs when merging changes

See Also:

Constant Field Values

Constructor Detail

CachingBOLoader

public CachingBOLoader(BOLoaderI _realBOLoader)

CachingBOLoader

public CachingBOLoader(BOLoaderI _realBOLoader,
                       CachingBOLoaderGCStrategyI _gcStrategy,
                       CachingBOLoaderUpdateStrategyI _updateStrategy)

CachingBOLoader

public CachingBOLoader(BOLoaderI _realBOLoader,
                       java.lang.Class[] _keepClasses,
                       int[] _maxKeeps)

Creates a caching bo loader with a default LRU strategy to limit the number of certain classes inside the cache. If a nonzero, positive interval is provided, then older instances will be removed by an automatic garbage collection thread.

See Also:

CachingBOLoaderLRUStrategy

CachingBOLoader

public CachingBOLoader(BOLoaderI _realBOLoader,
                       java.lang.Class[] _keepClasses,
                       int[] _maxKeeps,
                       int _interval)

Method Detail

close

public void close()

Closes the 'cache', dropping all cached values, stopping any update and gc collection threads. A closed cache cannot be used anymore

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

getInstrumentedInstance

public static CachingBOLoader getInstrumentedInstance(BOLoaderI _bol)

Creates a CachingBOLoader instance with an instrumented schema which allows to dynamically add new virtual attributes.

updateStrategies

public void updateStrategies(CachingBOLoaderGCStrategyI _gcStrategy,
                             CachingBOLoaderUpdateStrategyI _updateStrategy)

Replaces the current update and gc strategy with the provided ones. Stops the autoGC of the old strategy if possible. Updates the update subscriptions with the new updateStrategy.

setGCStrategy

public void setGCStrategy(CachingBOLoaderGCStrategyI _gcStrategy)

Stops a possibly running AutoGC on the old gcStrategy and replaces it with this instance. Does not automatically reschedule the new GC

setUpdateStrategy

public void setUpdateStrategy(CachingBOLoaderUpdateStrategyI _updateStrategy)

getBOT

public BOT getBOT(java.lang.Class<? extends BOI> clazz)

Specified by:

getBOT in interface BOLoaderI

Overrides:

getBOT in class BOLoaderWrapper

getBO

public BO getBO(java.lang.Long id)

Description copied from interface: BOLoaderI

wrapper for getBO(id, null). FIXME!! TT 2023-05-11: This method can probably return null in a few cases but I have no information what exactly these might be and it also depends on the actual implementing class. Also some implementations (DBMan for example) will throw ObjectNotPersistentException if no matching BO is found, while other implementations will not. Some classes - for example Mandant from crm-accounts module - will rely in ObjectNotPersistentException being thrown.

Specified by:

getBO in interface BOLoaderI

Overrides:

getBO in class BOLoaderWrapper

See Also:

BOLoaderI.getBO(Long, Class)

getBO

public BO getBO(java.lang.Long id,
                java.lang.Class<? extends BOI> classtip)

Description copied from interface: BOLoaderI

Returns the BO with the given id. If the BOLoader instance has an instance cache (like the Transaction class), then multiple calls to this method with the same id will return the exact same object, which means getBO(id,...)==getBO(id,...). The class tip is just what the name suggests, just a tip and will only have performance consequences if a wrong or null value is passed. FIXME!! TT 2023-05-11: This method can probably return null in a few cases but I have no information what exactly these might be and it also depends on the actual implementing class. Also some implementations (DBMan for example) will throw ObjectNotPersistentException if no matching BO is found, while other implementations will not. Some classes - for example Mandant from crm-accounts module - will rely in ObjectNotPersistentException being thrown.

Specified by:

getBO in interface BOLoaderI

Overrides:

getBO in class BOLoaderWrapper

Parameters:

id - the id of the BO

classtip - a guess which class the object has. May be null.

Returns:

BO with the given id.

getBOs

public BO[] getBOs(java.lang.Long[] ids)

Description copied from interface: BOLoaderI

wrapper for getBOs(ids, null)

Specified by:

getBOs in interface BOLoaderI

Overrides:

getBOs in class BOLoaderWrapper

See Also:

BOLoaderI.getBOs(Long[],Class)

getBOs

public BO[] getBOs(java.lang.Long[] ids,
                   java.lang.Class<? extends BOI> classtip)

Description copied from interface: BOLoaderI

returns the BOs with the given ids. If the BOLoader instance has an instance cache (like the Transaction class), then multiple calls to this method will return an array with the exact same objects. The class tip is common for all objects within this call and may be null.

Specified by:

getBOs in interface BOLoaderI

Overrides:

getBOs in class BOLoaderWrapper

Parameters:

ids - array of Longs with ids for the requested BOs.

classtip - guess for classes which the BOs belong to, may be null.

Returns:

BO[] with the requested BOs.

See Also:

Transaction

rescheduleGC

public void rescheduleGC(int interval)

Starts or stops a daemon, that clears the cache every interval seconds, but keeps a maximum number of instances of objects of types keepClasses specified in maxKeeps. If passed interval is negative, no daemon is started or it is asked to stop.

stopAutoGC

public void stopAutoGC()

Stops the daemon thread that automatically runs, if any.

subscribeForUpdatesViaEvents

public void subscribeForUpdatesViaEvents()

Register for BOChangeEvents so we can call replayProc for the relevant BPs which affect the keepClasses or their subclasses. Uses the current UpdateStrategy to determine the list of classes which are kept updated.

unsubscribeForUpdatesViaEvents

public void unsubscribeForUpdatesViaEvents()

Unsubscribes from any update registration, effectively letting objects in the cache go stale. If a cache went stale once, then resubscribing for events is not guaranteed to update all cached BOs to their latest version. The cache has to be drained if to guarantee that.

processDBManEvent

public void processDBManEvent(DBManEvent e)

Description copied from interface: DBManEventListenerI

Invoked when a subscribed DBManEvent occurs. See DBManBOChangeEvent for events triggered after modification on BOs.

Specified by:

processDBManEvent in interface DBManEventListenerI

updateCache

public void updateCache(DBManBOChangeEvent boce)

Does the actual merge and replay of a BO Change event.

updateCache

public void updateCache(BP bp,
                        java.util.Map<java.lang.Long,BO> affected,
                        CachingBOLoaderUpdateStrategyI myUpdateStrategy)

Checks the given BP against the current cache state and merges it if it appears to be needed in the cache.

Parameters:

bp - the BP to merge into the cache, nonnull.

affected - a Map containing BOs affected by the updating of the cache, will be updated if a new BO changed, nonnull.

myUpdateStrategy - the updateStrategy to check if this type of classes should be kept updated, nonnull

getSchema

public SchemaI getSchema()

Description copied from interface: BOLoaderI

gets a reference to the schema which is used by this BOLoader. Within the schema, you can find methods to set/get values, gather information about available entities and their attributes and many other things, too.

Specified by:

getSchema in interface BOLoaderI

Specified by:

getSchema in interface SchemaProviderI

Overrides:

getSchema in class BOLoaderWrapper

Returns:

the schema of this BOLoader instance.

assureInstrumentedSchema

public static BO[] assureInstrumentedSchema(BO[] _bos)

setRealBOLoader

public void setRealBOLoader(BOLoaderI _realBOLoader)

Sets the BOLoader to handle any cache misses with. Alias for ParentLoader

coerceBOLoader

public BO coerceBOLoader(BO bo)

Overrides:

coerceBOLoader in class BOLoaderWrapper

drain

public void drain()

If this BOLoader has a cache, we request it to empty it. The BOLoader should make every effort to keep valuable data though, but objects not "nailed" (=included in a transaction) should be reloaded or removed from the cache so that a further request will fetch them again. If BOLoaderI.isCaching() returns false, this is a nop. Sets the BOLoader of all cached BOs to the real BOLoader, which shouldn't be caching, and then clears the internal cache from all of them. As soon as the previously cached BOs are no longer referenced, they get gc'ed. Also resets the gcStrategy afterwards, because its roots are no longer valid.

Specified by:

drain in interface BOLoaderI

Specified by:

drain in interface BOLoaderWithCacheI

Overrides:

drain in class BOLoaderWrapper

getDrainCount

public int getDrainCount()

isCaching

public boolean isCaching()

Description copied from interface: BOLoaderI

If true, then this BOLoaderI uses an internal cache, holding all BOs hat were loaded or frapped into it. In this case, the BOLoader should not be expected to handle automatic cache eviction (some might). A BOLoader that is caching can be expected to deduplicate BOs with the same Id from different sources to create a stable, self contained BO graph. Caching BOLoaders should not be expected to always hold the most up to date version of a BO, even after frapping a newer BO with it, i.e. an already cached BO is might always be preferred. If false, then this BOLoader will not hold references to loaded BOs, allowing them to be garbage collected as soon as they're no longer referenced outside of this class. As a result, this Interface makes no guarantees regarding deduplication of BOs in the returned graph.

Specified by:

isCaching in interface BOLoaderI

Overrides:

isCaching in class BOLoaderWrapper

Returns:

true if this BOLoaderI uses a cache, false if loaded BOs aren't cached.

frapFromCache

public BO frapFromCache(BO bo)

Either returns the cached version for this BO or creates a deepcloned copy with this as BOLoader

Specified by:

frapFromCache in interface BOLoaderI

Overrides:

frapFromCache in class BOLoaderWrapper

frapBO

public BO frapBO(BO bo)

Coerces the BO Loader of the provided BO to this BOLoaderI on cache miss or returns the cached instance

frapEntries

public void frapEntries(java.util.Map mapForReplacingFrappedValues,
                        java.util.Iterator entriesIterator,
                        boolean cloneOnFrap,
                        java.util.Map<java.lang.Long,BO> tempCache)

Calls the 'frapBO' method on all map entries in the given iterator and potentially updates the values in the map the iterator is based on. If 'frapBO' returns a reference to a different instance of the original value, the map values are updated accordingly. If a map is explicitly passed as the first parameter, 'Map#replace' is used to replace the value. This is necessary in situations where the iterator is based on a map for which 'Map.Entry' does not support 'setValue', such as 'ConcurrentSkipListMap', for which the replace is even done atomically. If 'null' is passed as the map, 'Map.Entry#setValue' is called for replacing the value in the map the iterator is based on.

Parameters:

mapForReplacingFrappedValues - The map for replacing the value with the frapped instance (optional).

entriesIterator - An iterator for iterating through the map entries, on which 'frapBO(BO, boolean, Map)' will be called.

cloneOnFrap - The 'cloneOnFrap' mode that will be passed to 'frapBO(BO, boolean, Map)'.

tempCache - An internal helper map passed to 'frapBO' and used during recursive calls.

getMiniDesc

public java.lang.String getMiniDesc(BO bo)

isKnown

public boolean isKnown(java.lang.Long id)

returns true, if the passed Class is one of the keepClasses or a subclass of them

Specified by:

isKnown in interface BOLoaderWithCacheI

Returns:

true if there is currently a BO with this Id inside the cache. Doesn't fetch if missing

getKnown

public BO getKnown(java.lang.Long id)

Specified by:

getKnown in interface BOLoaderWithCacheI

Returns:

the cached instances of a BO with the passed Id or null if there is no cached BO for that Id yet.

getKnown

public java.util.Collection<BO> getKnown(java.lang.Class<? extends BOI> clazz)

Specified by:

getKnown in interface BOLoaderWithCacheI

Returns:

all known instances of clazz inside the cache. Might not be very performant

gc

public void gc(java.util.Map root)

Remove any BOs inside the cache that aren't reachable from the provided root-BOs. Map<Long, BO>

gc

public void gc(java.util.Iterator rootsIt)

Remove any BOs inside the cache that aren't reachable from any BO returned by the Iterator

transactionSaveSuccess

public void transactionSaveSuccess(Transaction stubTx,
                                   java.util.function.Predicate<Transaction> isSavedTransactionInstancePredicate)

Description copied from interface: SaveBOListenerI

Callback through which this SaveBOListenerI is notified about a successfully saved Transaction.

Specified by:

transactionSaveSuccess in interface SaveBOListenerI

Parameters:

stubTx - a stub clone of the Transaction which may be used for reacting upon changes

isSavedTransactionInstancePredicate - a Predicate which may be called for checking if a local tx is the same instance as the successfully saved Transaction and thus skipping any more processing

replayProc

public void replayProc(BOProc p,
                       java.util.Map<java.lang.Long,BO> affected)

Replays the provided BOProc on the cached object and adds the updated BO to the affected Map

addBOCacheListener

public void addBOCacheListener(BOCacheListenerI l)

Registers a BOCacheListenerI on this Object that is notified of any BO changes

removeBOCacheListener

public void removeBOCacheListener(BOCacheListenerI l)

Removes a previously registered BOCacheListenerI again