com.tangosol.coherence.hibernate
Class CoherenceCache

java.lang.Object
  com.tangosol.util.Base
      com.tangosol.coherence.hibernate.CoherenceCache

All Implemented Interfaces:

org.hibernate.cache.Cache

public class CoherenceCache
extends Base
implements org.hibernate.cache.Cache

Provides a cache wrapper for storing Hibernate objects in Coherence NamedCache instances.

Author:

jp 2005.08.31, jh 2005.08.31

Field Summary

protected static int	DEFAULT_LOCK_LEASE_MILLIS The default lock lease millis
protected static int	DEFAULT_LOCK_OBTAIN_MILLIS The default lock attempt millis
static String	LOCK_LEASE_TIMEOUT The system property specifying the lock lease timeout
static String	LOCK_OBTAIN_TIMEOUT The system property specifying the lock acquisition timeout

Constructor Summary

CoherenceCache(NamedCache cache, Properties properties)
Construct a Hibernate cache instance.

Method Summary

void	clear() Clear the entire cache.
void	destroy() Release local (JVM) resources associated with this cache.
Object	get(Object oKey) Get an object from the cache.
long	getElementCountInMemory() Get the size of the cache in memory (object count)
long	getElementCountOnDisk() Get the size of the cache on disk (object count)
protected int	getLockLeaseTimeout() Get the timeout (in millis) for lock leases.
protected int	getLockObtainTimeout() Get the timeout (in millis) for lock acquisition attempts.
String	getRegionName() Get the region (cache) name.
long	getSizeInMemory() Get the size of the cache in memory (byte count)
int	getTimeout() Get the lock timeout (lease duration, not lock acquisition).
protected long	getTimeProperty(Properties properties, String sPropertyName, long cDefaultMillis, long cMaxMillis) Get an adjusted time (duration) property
void	lock(Object oKey) Lock a key.
long	nextTimestamp() Get the current timestamp (in millis).
void	put(Object oKey, Object oValue) Put an object into the cache.
Object	read(Object oKey) Get an object from the cache.
void	remove(Object oKey) Remove an object from the cache.
Map	toMap() Get a Map instance representing the contents of the cache.
void	unlock(Object oKey) Unlock a key.
void	update(Object oKey, Object oValue) Update an item in the cache.

Field Detail

LOCK_OBTAIN_TIMEOUT

public static final String LOCK_OBTAIN_TIMEOUT

The system property specifying the lock acquisition timeout

See Also:

Constant Field Values

DEFAULT_LOCK_OBTAIN_MILLIS

protected static final int DEFAULT_LOCK_OBTAIN_MILLIS

The default lock attempt millis

See Also:

Constant Field Values

LOCK_LEASE_TIMEOUT

public static final String LOCK_LEASE_TIMEOUT

The system property specifying the lock lease timeout

See Also:

Constant Field Values

DEFAULT_LOCK_LEASE_MILLIS

protected static final int DEFAULT_LOCK_LEASE_MILLIS

The default lock lease millis

See Also:

Constant Field Values

Constructor Detail

CoherenceCache

public CoherenceCache(NamedCache cache,
                      Properties properties)

Construct a Hibernate cache instance.

Parameters:

cache - the Coherence NamedCache instance that provides the actual data storage

properties - the configuration properties

Method Detail

get

public Object get(Object oKey)

Get an object from the cache.

Specified by:

get in interface org.hibernate.cache.Cache

Parameters:

oKey - the cache key

Returns:

the cache value

read

public Object read(Object oKey)

Get an object from the cache.

Specified by:

read in interface org.hibernate.cache.Cache

Parameters:

oKey - the cache key

Returns:

the cache value

put

public void put(Object oKey,
                Object oValue)

Put an object into the cache.

Specified by:

put in interface org.hibernate.cache.Cache

Parameters:

oKey - the cache key

oValue - the cache value

remove

public void remove(Object oKey)

Remove an object from the cache.

Specified by:

remove in interface org.hibernate.cache.Cache

Parameters:

oKey - the cache key

clear

public void clear()

Clear the entire cache.

Specified by:

clear in interface org.hibernate.cache.Cache

destroy

public void destroy()

Release local (JVM) resources associated with this cache.

Specified by:

destroy in interface org.hibernate.cache.Cache

getTimeout

public int getTimeout()

Get the lock timeout (lease duration, not lock acquisition).

Specified by:

getTimeout in interface org.hibernate.cache.Cache

Returns:

the lock timeout in millis

nextTimestamp

public long nextTimestamp()

Get the current timestamp (in millis).

Specified by:

nextTimestamp in interface org.hibernate.cache.Cache

Returns:

the current timestamp

lock

public void lock(Object oKey)

Lock a key.

Specified by:

lock in interface org.hibernate.cache.Cache

Parameters:

oKey - the cache key

Throws:

org.hibernate.cache.CacheException - if lock acquisition times out

unlock

public void unlock(Object oKey)

Unlock a key.

Specified by:

unlock in interface org.hibernate.cache.Cache

Parameters:

oKey - the cache key

update

public void update(Object oKey,
                   Object oValue)

Update an item in the cache.

Specified by:

update in interface org.hibernate.cache.Cache

Parameters:

oKey - the cache key

oValue - the cache value

getRegionName

public String getRegionName()

Get the region (cache) name.

Specified by:

getRegionName in interface org.hibernate.cache.Cache

Returns:

the region (cache) name.

getSizeInMemory

public long getSizeInMemory()

Get the size of the cache in memory (byte count)

Not supported (returns -1).

Note: Used only by the Cache Statistics package

Specified by:

getSizeInMemory in interface org.hibernate.cache.Cache

Returns:

the number of bytes used by the cache

getElementCountInMemory

public long getElementCountInMemory()

Get the size of the cache in memory (object count)

Not supported (returns total cache size, including disk).

Note: Used only by the Cache Statistics package

Specified by:

getElementCountInMemory in interface org.hibernate.cache.Cache

Returns:

the number of objects in the cache that are in RAM

getElementCountOnDisk

public long getElementCountOnDisk()

Get the size of the cache on disk (object count)

Not supported (returns -1).

Note: Used only by the Cache Statistics package

Specified by:

getElementCountOnDisk in interface org.hibernate.cache.Cache

Returns:

the number of objects in the cache that are on disk

toMap

public Map toMap()

Get a Map instance representing the contents of the cache.

This implementation simply returns the Coherence NamedCache instance.

Specified by:

toMap in interface org.hibernate.cache.Cache

Returns:

the Map representation of the cache

getLockObtainTimeout

protected int getLockObtainTimeout()

Get the timeout (in millis) for lock acquisition attempts.

Returns:

the timeout (in millis)

getLockLeaseTimeout

protected int getLockLeaseTimeout()

Get the timeout (in millis) for lock leases.

Returns:

the timeout (in millis)

getTimeProperty

protected long getTimeProperty(Properties properties,
                               String sPropertyName,
                               long cDefaultMillis,
                               long cMaxMillis)

Get an adjusted time (duration) property

Parameters:

properties - the property set containing the property

sPropertyName - the name of the property

cDefaultMillis - the default value (in milliseconds)

cMaxMillis - the maximum value (saturating, in milliseconds)

Returns:

the time value