Package org.opends.server.extensions
Class DefaultEntryCache
- java.lang.Object
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- org.opends.server.api.MonitorProvider
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- org.opends.server.api.EntryCache<EntryCacheCfg>
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- org.opends.server.extensions.DefaultEntryCache
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- All Implemented Interfaces:
MeterBinder
,ConfigurationChangeListener<EntryCacheCfg>
,LocalBackendInitializationListener
public final class DefaultEntryCache extends EntryCache<EntryCacheCfg> implements ConfigurationChangeListener<EntryCacheCfg>, LocalBackendInitializationListener
This class defines the default entry cache which acts as an arbiter for every entry cache implementation configured and installed within the Directory Server or acts an an empty cache if no implementation specific entry cache is configured. It does not actually store any entries, so all calls to the entry cache public API are routed to underlying entry cache according to the current configuration order and preferences.This class records total-tries and misses metrics globally:
- Try to retrieve an entry from multiple cache implementations: record one try.
- None of the entry cache implementations have succeeded to retrieve the entry: record one miss.
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Field Summary
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Fields inherited from class org.opends.server.api.MonitorProvider
registry
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Constructor Summary
Constructors Constructor Description DefaultEntryCache()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description ConfigChangeResult
applyConfigurationChange(EntryCacheCfg configuration)
Applies the configuration changes to this change listener.void
clear()
Removes all entries from the cache.void
clearBackend(String backendID)
Removes all entries from the cache that are associated with the provided backend.protected Dn
computeMonitorInstanceDn()
Returns the monitor instance DN for this monitor provider.boolean
containsEntry(Dn entryDN)
Indicates whether the entry cache currently contains the entry with the specified DN.void
finalizeEntryCache()
Performs any necessary cleanup work (e.g., flushing all cached entries and releasing any other held resources) that should be performed when the server is to be shut down or the entry cache destroyed or replaced.SizedEntry
getEntry(String backendID, long entryID)
Retrieves the requested entry with its size, if it is present in the cache.SizedEntry
getEntry(Dn entryDN)
Retrieves the entry with its size, with the specified DN from the cache.long
getEntryCount()
Retrieves the current number of entries stored within the cache.Dn
getEntryDN(String backendID, long entryID)
Retrieves the entry DN for the entry with the specified ID on the specific backend from the cache.void
handleLowMemory()
Attempts to react to a scenario in which it is determined that the system is running low on available memory.void
initializeEntryCache(ServerContext serverContext, EntryCacheCfg configuration)
Initializes this entry cache implementation so that it will be available for storing and retrieving entries.boolean
isConfigurationChangeAcceptable(EntryCacheCfg configuration, List<LocalizableMessage> unacceptableReasons)
Indicates whether the proposed change to the configuration is acceptable to this change listener.protected MeterRegistryHolder
newMeterRegistryHolder(MeterRegistry parent)
Creates aMeterRegistryHolder
with the appropriate name prefixes and tags.void
performBackendPostFinalizationProcessing(LocalBackend<?> backend)
Performs any processing that may be required whenever a backend is finalized.void
putEntry(SizedEntry entry, String backendID, long entryID)
Stores the provided entry in the cache.boolean
putEntryIfAbsent(SizedEntry entry, String backendID, long entryID)
Stores the provided entry in the cache only if it does not conflict with an entry that already exists.protected void
recordMiss()
Records a failure to retrieve an entry from this cache.protected void
recordTry()
Records an attempt to retrieve an entry from this cache.void
removeEntry(Dn entryDN)
Removes the specified entry from the cache.static void
setCacheOrder(SortedMap<Integer,EntryCache<? extends EntryCacheCfg>> cacheOrderMap)
Sets the current cache order array.String
toVerboseString()
Return a verbose string representation of the current cache maps.-
Methods inherited from class org.opends.server.api.EntryCache
addMonitorObjectClassNames, bindTo, filtersAllowCaching, getServerContext, isConfigurationAcceptable, setIncludeExcludeFilters
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Methods inherited from class org.opends.server.api.MonitorProvider
configurationDnToMonitorDn, deregisterAll, getMonitorEntry, getMonitorInstanceDn, toString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.opends.server.api.LocalBackendInitializationListener
performBackendPostInitializationProcessing, performBackendPreFinalizationProcessing, performBackendPreInitializationProcessing
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Method Detail
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initializeEntryCache
public void initializeEntryCache(ServerContext serverContext, EntryCacheCfg configuration) throws ConfigException, InitializationException
Description copied from class:EntryCache
Initializes this entry cache implementation so that it will be available for storing and retrieving entries.- Overrides:
initializeEntryCache
in classEntryCache<EntryCacheCfg>
- Parameters:
serverContext
- The server context.configuration
- The configuration to use to initialize the entry cache.- Throws:
ConfigException
- If there is a problem with the provided configuration entry that would prevent this entry cache from being used.InitializationException
- If a problem occurs during the initialization process that is not related to the configuration.
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containsEntry
public boolean containsEntry(Dn entryDN)
Description copied from class:EntryCache
Indicates whether the entry cache currently contains the entry with the specified DN. This method may be called without holding any locks if a point-in-time check is all that is required. Note that this method is called from @see #getEntry(DN entryDN, LockType lockType, List lockList)- Specified by:
containsEntry
in classEntryCache<EntryCacheCfg>
- Parameters:
entryDN
- The DN for which to make the determination.- Returns:
true
if the entry cache currently contains the entry with the specified DN, orfalse
if not.
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getEntry
public SizedEntry getEntry(String backendID, long entryID)
Description copied from class:EntryCache
Retrieves the requested entry with its size, if it is present in the cache.- Overrides:
getEntry
in classEntryCache<EntryCacheCfg>
- Parameters:
backendID
- ID of the backend associated with the entry to retrieve.entryID
- The entry ID within the provided backend for the specified entry.- Returns:
- The requested entry if it is present in the cache, or
null
if it is not present.
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getEntry
public SizedEntry getEntry(Dn entryDN)
Description copied from class:EntryCache
Retrieves the entry with its size, with the specified DN from the cache.- Specified by:
getEntry
in classEntryCache<EntryCacheCfg>
- Parameters:
entryDN
- The DN of the entry to retrieve.- Returns:
- The requested entry with its size if it is present in the cache, or
null
if it is not present.
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getEntryDN
public Dn getEntryDN(String backendID, long entryID)
Description copied from class:EntryCache
Retrieves the entry DN for the entry with the specified ID on the specific backend from the cache. The caller should have already acquired a read or write lock for the entry if such protection is needed. Note that this method is called from @see #getEntry(Backend backend, long entryID, LockType lockType, List lockList)- Specified by:
getEntryDN
in classEntryCache<EntryCacheCfg>
- Parameters:
backendID
- ID of the backend associated with the entry for which to retrieve the entry DN.entryID
- The entry ID within the provided backend for which to retrieve the entry DN.- Returns:
- The entry DN for the requested entry, or
null
if it is not present in the cache.
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putEntry
public void putEntry(SizedEntry entry, String backendID, long entryID)
Description copied from class:EntryCache
Stores the provided entry in the cache. Note that the mechanism that it uses to achieve this is implementation-dependent, and it is acceptable for the entry to not actually be stored in any cache.- Specified by:
putEntry
in classEntryCache<EntryCacheCfg>
- Parameters:
entry
- The entry to store in the cache.backendID
- ID of the backend with which the entry is associated.entryID
- The entry ID within the provided backend that uniquely identifies the specified entry.
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putEntryIfAbsent
public boolean putEntryIfAbsent(SizedEntry entry, String backendID, long entryID)
Description copied from class:EntryCache
Stores the provided entry in the cache only if it does not conflict with an entry that already exists. Note that the mechanism that it uses to achieve this is implementation-dependent, and it is acceptable for the entry to not actually be stored in any cache. However, this method must not overwrite an existing version of the entry.- Specified by:
putEntryIfAbsent
in classEntryCache<EntryCacheCfg>
- Parameters:
entry
- The entry to store in the cache.backendID
- ID of the backend with which the entry is associated.entryID
- The entry ID within the provided backend that uniquely identifies the specified entry.- Returns:
false
if an existing entry or some other problem prevented the method from completing successfully, ortrue
if there was no conflict and the entry was either stored or the cache determined that this entry should never be cached for some reason.
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removeEntry
public void removeEntry(Dn entryDN)
Description copied from class:EntryCache
Removes the specified entry from the cache.- Specified by:
removeEntry
in classEntryCache<EntryCacheCfg>
- Parameters:
entryDN
- The DN of the entry to remove from the cache.
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clear
public void clear()
Description copied from class:EntryCache
Removes all entries from the cache. The cache should still be available for future use.- Specified by:
clear
in classEntryCache<EntryCacheCfg>
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clearBackend
public void clearBackend(String backendID)
Description copied from class:EntryCache
Removes all entries from the cache that are associated with the provided backend.- Specified by:
clearBackend
in classEntryCache<EntryCacheCfg>
- Parameters:
backendID
- ID of the backend for which to flush the associated entries.
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handleLowMemory
public void handleLowMemory()
Description copied from class:EntryCache
Attempts to react to a scenario in which it is determined that the system is running low on available memory. In this case, the entry cache should attempt to free some memory if possible to try to avoid out of memory errors.- Specified by:
handleLowMemory
in classEntryCache<EntryCacheCfg>
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isConfigurationChangeAcceptable
public boolean isConfigurationChangeAcceptable(EntryCacheCfg configuration, List<LocalizableMessage> unacceptableReasons)
Description copied from interface:ConfigurationChangeListener
Indicates whether the proposed change to the configuration is acceptable to this change listener.- Specified by:
isConfigurationChangeAcceptable
in interfaceConfigurationChangeListener<EntryCacheCfg>
- Parameters:
configuration
- The new configuration containing the changes.unacceptableReasons
- A list that can be used to hold messages about why the provided configuration is not acceptable.- Returns:
- Returns
true
if the proposed change is acceptable, orfalse
if it is not.
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applyConfigurationChange
public ConfigChangeResult applyConfigurationChange(EntryCacheCfg configuration)
Description copied from interface:ConfigurationChangeListener
Applies the configuration changes to this change listener.- Specified by:
applyConfigurationChange
in interfaceConfigurationChangeListener<EntryCacheCfg>
- Parameters:
configuration
- The new configuration containing the changes.- Returns:
- Returns information about the result of changing the configuration.
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getEntryCount
public long getEntryCount()
Description copied from class:EntryCache
Retrieves the current number of entries stored within the cache.- Specified by:
getEntryCount
in classEntryCache<EntryCacheCfg>
- Returns:
- The current number of entries stored within the cache.
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toVerboseString
public String toVerboseString()
Description copied from class:EntryCache
Return a verbose string representation of the current cache maps. This is useful primary for debugging and diagnostic purposes such as in the entry cache unit tests.This method is invoked by unit tests for debugging.
- Specified by:
toVerboseString
in classEntryCache<EntryCacheCfg>
- Returns:
- String verbose string representation of the current cache maps in the following format: dn:id:backend one
cache entry map representation per line or
null
if all maps are empty.
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setCacheOrder
public static void setCacheOrder(SortedMap<Integer,EntryCache<? extends EntryCacheCfg>> cacheOrderMap)
Sets the current cache order array.- Parameters:
cacheOrderMap
- The current cache order array.
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performBackendPostFinalizationProcessing
public void performBackendPostFinalizationProcessing(LocalBackend<?> backend)
Description copied from interface:LocalBackendInitializationListener
Performs any processing that may be required whenever a backend is finalized. This method will be invoked after the backend has been taken out of service but before it has been finalized.- Specified by:
performBackendPostFinalizationProcessing
in interfaceLocalBackendInitializationListener
- Parameters:
backend
- The backend that has been taken out of service and is about to be finalized.
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computeMonitorInstanceDn
protected Dn computeMonitorInstanceDn()
Description copied from class:MonitorProvider
Returns the monitor instance DN for this monitor provider.- Overrides:
computeMonitorInstanceDn
in classEntryCache<EntryCacheCfg>
- Returns:
- the monitor instance DN.
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newMeterRegistryHolder
protected MeterRegistryHolder newMeterRegistryHolder(MeterRegistry parent)
Description copied from class:EntryCache
Creates aMeterRegistryHolder
with the appropriate name prefixes and tags.- Overrides:
newMeterRegistryHolder
in classEntryCache<EntryCacheCfg>
- Parameters:
parent
- The meter registry to be decorated.- Returns:
- The meter registry holder.
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finalizeEntryCache
public void finalizeEntryCache()
Description copied from class:EntryCache
Performs any necessary cleanup work (e.g., flushing all cached entries and releasing any other held resources) that should be performed when the server is to be shut down or the entry cache destroyed or replaced.- Specified by:
finalizeEntryCache
in classEntryCache<EntryCacheCfg>
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recordTry
protected void recordTry()
Description copied from class:EntryCache
Records an attempt to retrieve an entry from this cache.- Overrides:
recordTry
in classEntryCache<EntryCacheCfg>
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recordMiss
protected void recordMiss()
Description copied from class:EntryCache
Records a failure to retrieve an entry from this cache.- Overrides:
recordMiss
in classEntryCache<EntryCacheCfg>
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