Package org.apache.hadoop.hdfs.server.federation.store

Class CachedRecordStore<R extends BaseRecord>

java.lang.Object

org.apache.hadoop.hdfs.server.federation.store.RecordStore<R>

org.apache.hadoop.hdfs.server.federation.store.CachedRecordStore<R>

Type Parameters:

R - Record to store by this interface.

All Implemented Interfaces:

StateStoreCache

Direct Known Subclasses:

DisabledNameserviceStore, MembershipStore, MountTableStore, RouterStore

public abstract class CachedRecordStore<R extends BaseRecord>
extends RecordStore<R>
implements StateStoreCache

Record store that takes care of caching the records in memory.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	CachedRecordStore(Class<R> clazz, StateStoreDriver driver)	Create a new cached record store.
protected	CachedRecordStore(Class<R> clazz, StateStoreDriver driver, boolean over)	Create a new cached record store.

Method Summary

Modifier and Type	Method	Description
List<R>	getCachedRecords()	Get all the cached records.
protected QueryResult<R>	getCachedRecordsAndTimeStamp()	Get all the cached records and the time stamp of the cache.
boolean	loadCache(boolean force)	Load the cache from the State Store.
void	overrideExpiredRecord(R record)	Updates the state store with any record overrides we detected, such as an expired state.
void	overrideExpiredRecords(QueryResult<R> query)	Updates the state store with any record overrides we detected, such as an expired state.

Methods inherited from class org.apache.hadoop.hdfs.server.federation.store.RecordStore

getDriver, getRecordClass, newInstance

Methods inherited from class java.lang.Object

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

Constructor Details

CachedRecordStore

protected CachedRecordStore(Class<R> clazz,
 StateStoreDriver driver)

Create a new cached record store.

Parameters:

clazz - Class of the record to store.

driver - State Store driver.

CachedRecordStore

protected CachedRecordStore(Class<R> clazz,
 StateStoreDriver driver,
 boolean over)

Create a new cached record store.

Parameters:

clazz - Class of the record to store.

driver - State Store driver.

over - If the entries should be overridden if they expire

Method Details

loadCache

public boolean loadCache(boolean force)
                  throws IOException

Description copied from interface: StateStoreCache

Load the cache from the State Store. Called by the cache update service when the data has been reloaded.

Specified by:

loadCache in interface StateStoreCache

Parameters:

force - If we force the load.

Returns:

If the cache was loaded successfully.

Throws:

IOException - If there was an error loading the cache.

overrideExpiredRecords

public void overrideExpiredRecords(QueryResult<R> query)
                            throws IOException

Updates the state store with any record overrides we detected, such as an expired state. If an expired record exists beyond deletion time, it is removed.

Parameters:

query - RecordQueryResult containing the data to be inspected.

Throws:

IOException - If the values cannot be updated.

overrideExpiredRecord

public void overrideExpiredRecord(R record)
                           throws IOException

Updates the state store with any record overrides we detected, such as an expired state.

Parameters:

record - record to be updated.

Throws:

IOException - If the values cannot be updated.

getCachedRecords

public List<R> getCachedRecords()
                         throws StateStoreUnavailableException

Get all the cached records.

Returns:

Copy of the cached records.

Throws:

StateStoreUnavailableException - If the State store is not available.

getCachedRecordsAndTimeStamp

protected QueryResult<R> getCachedRecordsAndTimeStamp()
                                               throws StateStoreUnavailableException

Get all the cached records and the time stamp of the cache.

Returns:

Copy of the cached records and the time stamp.

Throws:

StateStoreUnavailableException - If the State store is not available.