ehcache

net.sf.ehcache
Class Cache

java.lang.Object
  extended by net.sf.ehcache.Cache
All Implemented Interfaces:
java.lang.Cloneable

public final class Cache
extends java.lang.Object
implements java.lang.Cloneable

Cache is the central class in ehcache. Caches have Elements and are managed by the CacheManager. The Cache performs logical actions. It delegates physical implementations to its Stores.

A reference to a Cache can be obtained through the CacheManager. A Cache thus obtained is guaranteed to have status Status.STATUS_ALIVE. This status is checked for any method which throws IllegalStateException and the same thrown if it is not alive. This would normally happen if a call is made after CacheManager.shutdown() is invoked.

Cache is threadsafe.

Statistics on cache usage are collected and made available through public methods.

Version:
$Id: Cache.java 52 2006-04-24 14:50:03Z gregluck $
Author:
Greg Luck

Field Summary
static java.lang.String DEFAULT_CACHE_NAME
          A reserved word for cache names.
static long DEFAULT_EXPIRY_THREAD_INTERVAL_SECONDS
          The default interval between runs of the expiry thread.
static java.lang.String NET_SF_EHCACHE_DISABLED
          System Property based method of disabling ehcache.
 
Constructor Summary
Cache(java.lang.String name, int maxElementsInMemory, boolean overflowToDisk, boolean eternal, long timeToLiveSeconds, long timeToIdleSeconds)
          1.0 Constructor.
Cache(java.lang.String name, int maxElementsInMemory, boolean overflowToDisk, boolean eternal, long timeToLiveSeconds, long timeToIdleSeconds, boolean diskPersistent, long diskExpiryThreadIntervalSeconds)
          1.1 Constructor.
Cache(java.lang.String name, int maxElementsInMemory, MemoryStoreEvictionPolicy memoryStoreEvictionPolicy, boolean overflowToDisk, java.lang.String diskStorePath, boolean eternal, long timeToLiveSeconds, long timeToIdleSeconds, boolean diskPersistent, long diskExpiryThreadIntervalSeconds, RegisteredEventListeners registeredEventListeners)
          1.2 Constructor

The ConfigurationFactory and clients can create these.

 
Method Summary
 long calculateInMemorySize()
          Gets the size of the memory store for this cache

Warning: This method can be very expensive to run.

 java.lang.Object clone()
          Clones a cache.
(package private)  void dispose()
          Flushes all cache items from memory to auxilliary caches and close the auxilliary caches.
 void flush()
          Flushes all cache items from memory to the disk store, and from the DiskStore to disk.
 Element get(java.lang.Object key)
          Gets an element from the cache.
 Element get(java.io.Serializable key)
          Gets an element from the cache.
 RegisteredEventListeners getCacheEventNotificationService()
          Use this to access the service in order to register and unregister listeners
 CacheManager getCacheManager()
          Gets the CacheManager managing this cache.
 long getDiskExpiryThreadIntervalSeconds()
           
(package private)  DiskStore getDiskStore()
          Gets the internal DiskStore.
 int getDiskStoreHitCount()
          Number of times a requested item was found in the Disk Store.
 int getDiskStoreSize()
          Returns the number of elements in the disk store.
 java.lang.String getGuid()
          The GUID for this cache instance can be used to determine whether two cache instance references are pointing to the same cache.
 int getHitCount()
          The number of times a requested item was found in the cache.
 java.util.List getKeys()
          Returns a list of all elements in the cache, whether or not they are expired.
 java.util.List getKeysNoDuplicateCheck()
          Returns a list of all elements in the cache, whether or not they are expired.
 java.util.List getKeysWithExpiryCheck()
          Returns a list of all elements in the cache.
 int getMaxElementsInMemory()
          Gets the maximum number of elements to hold in memory.
(package private)  MemoryStore getMemoryStore()
          Gets the internal MemoryStore.
 MemoryStoreEvictionPolicy getMemoryStoreEvictionPolicy()
          The policy used to evict elements from the MemoryStore.
 int getMemoryStoreHitCount()
          Number of times a requested item was found in the Memory Store.
 long getMemoryStoreSize()
          Returns the number of elements in the memory store.
 int getMissCountExpired()
          Number of times a requested element was found but was expired.
 int getMissCountNotFound()
          Number of times a requested element was not found in the cache.
 java.lang.String getName()
          Gets the cache name.
 Element getQuiet(java.lang.Object key)
          Gets an element from the cache, without updating Element statistics.
 Element getQuiet(java.io.Serializable key)
          Gets an element from the cache, without updating Element statistics.
 int getSize()
          Gets the size of the cache.
 Status getStatus()
          Gets the status attribute of the Cache.
 long getTimeToIdleSeconds()
          Gets timeToIdleSeconds.
 long getTimeToLiveSeconds()
          Gets timeToLiveSeconds.
(package private)  void initialise()
          Newly created caches do not have a MemoryStore or a DiskStore.
 boolean isDiskPersistent()
           
 boolean isElementInMemory(java.lang.Object key)
          Whether an Element is stored in the cache in Memory, indicating a very low cost of retrieval.
 boolean isElementInMemory(java.io.Serializable key)
          Whether an Element is stored in the cache in Memory, indicating a very low cost of retrieval.
 boolean isElementOnDisk(java.lang.Object key)
          Whether an Element is stored in the cache on Disk, indicating a higher cost of retrieval.
 boolean isElementOnDisk(java.io.Serializable key)
          Whether an Element is stored in the cache on Disk, indicating a higher cost of retrieval.
 boolean isEternal()
          Are elements eternal.
 boolean isExpired(Element element)
          Checks whether this cache element has expired.
 boolean isOverflowToDisk()
          Does the overflow go to disk.
 void put(Element element)
          Put an element in the cache.
 void put(Element element, boolean doNotNotifyCacheReplicators)
          Put an element in the cache.
 void putQuiet(Element element)
          Put an element in the cache, without updating statistics, or updating listeners.
 boolean remove(java.lang.Object key)
          Removes an Element from the Cache.
 boolean remove(java.lang.Object key, boolean doNotNotifyCacheReplicators)
          Removes an Element from the Cache.
 boolean remove(java.io.Serializable key)
          Removes an Element from the Cache.
 boolean remove(java.io.Serializable key, boolean doNotNotifyCacheReplicators)
          Removes an Element from the Cache.
 void removeAll()
          Removes all cached items.
 boolean removeQuiet(java.lang.Object key)
          Removes an Element from the Cache, without notifying listeners.
 boolean removeQuiet(java.io.Serializable key)
          Removes an Element from the Cache, without notifying listeners.
(package private)  void setCacheManager(CacheManager cacheManager)
          Package local setter for use by CacheManager
(package private)  void setName(java.lang.String name)
          Sets the cache name which will name.
 java.lang.String toString()
          Returns a String representation of Cache.
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

DEFAULT_CACHE_NAME

public static final java.lang.String DEFAULT_CACHE_NAME
A reserved word for cache names. It denotes a default configuration which is applied to caches created without configuration.

See Also:
Constant Field Values

NET_SF_EHCACHE_DISABLED

public static final java.lang.String NET_SF_EHCACHE_DISABLED
System Property based method of disabling ehcache. If disabled no elements will be added to a cache.

Set the property "net.sf.ehcache.disabled=true" to disable ehcache.

This can easily be done using java -Dnet.sf.ehcache.disabled=true in the command line.

See Also:
Constant Field Values

DEFAULT_EXPIRY_THREAD_INTERVAL_SECONDS

public static final long DEFAULT_EXPIRY_THREAD_INTERVAL_SECONDS
The default interval between runs of the expiry thread.

See Also:
Constant Field Values
Constructor Detail

Cache

public Cache(java.lang.String name,
             int maxElementsInMemory,
             boolean overflowToDisk,
             boolean eternal,
             long timeToLiveSeconds,
             long timeToIdleSeconds)
1.0 Constructor.

The ConfigurationFactory and clients can create these.

A client can specify their own settings here and pass the Cache object into CacheManager.addCache(java.lang.String) to specify parameters other than the defaults.

Only the CacheManager can initialise them.

This constructor creates disk stores, if specified, that do not persist between restarts.

The default expiry thread interval of 120 seconds is used. This is the interval between runs of the expiry thread, where it checks the disk store for expired elements. It is not the the timeToLiveSeconds.

Parameters:
name - Cache name
maxElementsInMemory - Max elements in memory
overflowToDisk - Overflow to disk (boolean)
eternal - Whether the elements expire
timeToLiveSeconds -
timeToIdleSeconds -
Since:
1.0

Cache

public Cache(java.lang.String name,
             int maxElementsInMemory,
             boolean overflowToDisk,
             boolean eternal,
             long timeToLiveSeconds,
             long timeToIdleSeconds,
             boolean diskPersistent,
             long diskExpiryThreadIntervalSeconds)
1.1 Constructor.

The ConfigurationFactory and clients can create these.

A client can specify their own settings here and pass the Cache object into CacheManager.addCache(java.lang.String) to specify parameters other than the defaults.

Only the CacheManager can initialise them.

Parameters:
name -
maxElementsInMemory -
overflowToDisk -
eternal -
timeToLiveSeconds -
timeToIdleSeconds -
diskPersistent -
diskExpiryThreadIntervalSeconds -
Since:
1.1

Cache

public Cache(java.lang.String name,
             int maxElementsInMemory,
             MemoryStoreEvictionPolicy memoryStoreEvictionPolicy,
             boolean overflowToDisk,
             java.lang.String diskStorePath,
             boolean eternal,
             long timeToLiveSeconds,
             long timeToIdleSeconds,
             boolean diskPersistent,
             long diskExpiryThreadIntervalSeconds,
             RegisteredEventListeners registeredEventListeners)
1.2 Constructor

The ConfigurationFactory and clients can create these.

A client can specify their own settings here and pass the Cache object into CacheManager.addCache(java.lang.String) to specify parameters other than the defaults.

Only the CacheManager can initialise them.

Parameters:
name -
maxElementsInMemory -
memoryStoreEvictionPolicy - one of LRU, LFU and FIFO. Optionally null, in which case it will be set to LRU.
overflowToDisk -
diskStorePath -
eternal -
timeToLiveSeconds -
timeToIdleSeconds -
diskPersistent -
diskExpiryThreadIntervalSeconds -
registeredEventListeners - a notification service. Optionally null, in which case a new one with no registered listeners will be created.
Since:
1.2
Method Detail

initialise

final void initialise()
Newly created caches do not have a MemoryStore or a DiskStore.

This method creates those and makes the cache ready to accept elements


put

public final void put(Element element)
               throws java.lang.IllegalArgumentException,
                      java.lang.IllegalStateException,
                      CacheException
Put an element in the cache.

Resets the access statistics on the element, which would be the case if it has previously been gotten from a cache, and is now being put back.

Also notifies the CacheEventListener that:

Parameters:
element - An object. If Serializable it can fully participate in replication and the DiskStore.
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
java.lang.IllegalArgumentException - if the element is null
CacheException

put

public final void put(Element element,
                      boolean doNotNotifyCacheReplicators)
               throws java.lang.IllegalArgumentException,
                      java.lang.IllegalStateException,
                      CacheException
Put an element in the cache.

Resets the access statistics on the element, which would be the case if it has previously been gotten from a cache, and is now being put back.

Also notifies the CacheEventListener that:

Parameters:
element - An object. If Serializable it can fully participate in replication and the DiskStore.
doNotNotifyCacheReplicators - whether the put is coming from a doNotNotifyCacheReplicators cache peer, in which case this put should not initiate a further notification to doNotNotifyCacheReplicators cache peers
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
java.lang.IllegalArgumentException - if the element is null
CacheException

putQuiet

public final void putQuiet(Element element)
                    throws java.lang.IllegalArgumentException,
                           java.lang.IllegalStateException,
                           CacheException
Put an element in the cache, without updating statistics, or updating listeners. This is meant to be used in conjunction with getQuiet(java.io.Serializable)

Parameters:
element - An object. If Serializable it can fully participate in replication and the DiskStore.
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
java.lang.IllegalArgumentException - if the element is null
CacheException

get

public final Element get(java.io.Serializable key)
                  throws java.lang.IllegalStateException,
                         CacheException
Gets an element from the cache. Updates Element Statistics

Note that the Element's lastAccessTime is always the time of this get. Use getQuiet(Object) to peak into the Element to see its last access time with get

Parameters:
key - a serializable value
Returns:
the element, or null, if it does not exist.
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
CacheException
See Also:
isExpired(net.sf.ehcache.Element)

get

public final Element get(java.lang.Object key)
                  throws java.lang.IllegalStateException,
                         CacheException
Gets an element from the cache. Updates Element Statistics

Note that the Element's lastAccessTime is always the time of this get. Use getQuiet(Object) to peak into the Element to see its last access time with get

Parameters:
key - an Object value
Returns:
the element, or null, if it does not exist.
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
CacheException
Since:
1.2
See Also:
isExpired(net.sf.ehcache.Element)

getQuiet

public final Element getQuiet(java.io.Serializable key)
                       throws java.lang.IllegalStateException,
                              CacheException
Gets an element from the cache, without updating Element statistics. Cache statistics are still updated.

Parameters:
key - a serializable value
Returns:
the element, or null, if it does not exist.
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
CacheException
See Also:
isExpired(net.sf.ehcache.Element)

getQuiet

public final Element getQuiet(java.lang.Object key)
                       throws java.lang.IllegalStateException,
                              CacheException
Gets an element from the cache, without updating Element statistics. Cache statistics are still updated.

Parameters:
key - a serializable value
Returns:
the element, or null, if it does not exist.
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
CacheException
Since:
1.2
See Also:
isExpired(net.sf.ehcache.Element)

getKeys

public final java.util.List getKeys()
                             throws java.lang.IllegalStateException,
                                    CacheException
Returns a list of all elements in the cache, whether or not they are expired.

The returned keys are unique and can be considered a set.

The List returned is not live. It is a copy.

The time taken is O(n). On a single cpu 1.8Ghz P4, approximately 8ms is required for each 1000 entries.

Returns:
a list of Object keys
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
CacheException

getKeysWithExpiryCheck

public final java.util.List getKeysWithExpiryCheck()
                                            throws java.lang.IllegalStateException,
                                                   CacheException
Returns a list of all elements in the cache. Only keys of non-expired elements are returned.

The returned keys are unique and can be considered a set.

The List returned is not live. It is a copy.

The time taken is O(n), where n is the number of elements in the cache. On a 1.8Ghz P4, the time taken is approximately 200ms per 1000 entries. This method is not syncrhonized, because it relies on a non-live list returned from getKeys() , which is synchronised, and which takes 8ms per 1000 entries. This way cache liveness is preserved, even if this method is very slow to return.

Consider whether your usage requires checking for expired keys. Because this method takes so long, depending on cache settings, the list could be quite out of date by the time you get it.

Returns:
a list of Object keys
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
CacheException

getKeysNoDuplicateCheck

public final java.util.List getKeysNoDuplicateCheck()
                                             throws java.lang.IllegalStateException
Returns a list of all elements in the cache, whether or not they are expired.

The returned keys are not unique and may contain duplicates. If the cache is only using the memory store, the list will be unique. If the disk store is being used as well, it will likely contain duplicates, because of the internal store design.

The List returned is not live. It is a copy.

The time taken is O(log n). On a single cpu 1.8Ghz P4, approximately 6ms is required for 1000 entries and 36 for 50000.

This is the fastest getKeys method

Returns:
a list of Object keys
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

remove

public final boolean remove(java.io.Serializable key)
                     throws java.lang.IllegalStateException
Removes an Element from the Cache. This also removes it from any stores it may be in.

Also notifies the CacheEventListener after the element was removed, but only if an Element with the key actually existed.

Parameters:
key -
Returns:
true if the element was removed, false if it was not found in the cache
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

remove

public final boolean remove(java.lang.Object key)
                     throws java.lang.IllegalStateException
Removes an Element from the Cache. This also removes it from any stores it may be in.

Also notifies the CacheEventListener after the element was removed, but only if an Element with the key actually existed.

Parameters:
key -
Returns:
true if the element was removed, false if it was not found in the cache
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
Since:
1.2

remove

public final boolean remove(java.io.Serializable key,
                            boolean doNotNotifyCacheReplicators)
                     throws java.lang.IllegalStateException
Removes an Element from the Cache. This also removes it from any stores it may be in.

Also notifies the CacheEventListener after the element was removed, but only if an Element with the key actually existed.

Parameters:
key -
doNotNotifyCacheReplicators - whether the put is coming from a doNotNotifyCacheReplicators cache peer, in which case this put should not initiate a further notification to doNotNotifyCacheReplicators cache peers
Returns:
true if the element was removed, false if it was not found in the cache
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

remove

public final boolean remove(java.lang.Object key,
                            boolean doNotNotifyCacheReplicators)
                     throws java.lang.IllegalStateException
Removes an Element from the Cache. This also removes it from any stores it may be in.

Also notifies the CacheEventListener after the element was removed, but only if an Element with the key actually existed.

Parameters:
key -
doNotNotifyCacheReplicators - whether the put is coming from a doNotNotifyCacheReplicators cache peer, in which case this put should not initiate a further notification to doNotNotifyCacheReplicators cache peers
Returns:
true if the element was removed, false if it was not found in the cache
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

removeQuiet

public final boolean removeQuiet(java.io.Serializable key)
                          throws java.lang.IllegalStateException
Removes an Element from the Cache, without notifying listeners. This also removes it from any stores it may be in.

Parameters:
key -
Returns:
true if the element was removed, false if it was not found in the cache
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

removeQuiet

public final boolean removeQuiet(java.lang.Object key)
                          throws java.lang.IllegalStateException
Removes an Element from the Cache, without notifying listeners. This also removes it from any stores it may be in.

Parameters:
key -
Returns:
true if the element was removed, false if it was not found in the cache
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
Since:
1.2

removeAll

public final void removeAll()
                     throws java.lang.IllegalStateException,
                            java.io.IOException,
                            CacheException
Removes all cached items.

Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
java.io.IOException
CacheException

dispose

final void dispose()
            throws java.lang.IllegalStateException
Flushes all cache items from memory to auxilliary caches and close the auxilliary caches.

Should be invoked only by CacheManager.

Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

flush

public final void flush()
                 throws java.lang.IllegalStateException,
                        CacheException
Flushes all cache items from memory to the disk store, and from the DiskStore to disk.

Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
CacheException

getSize

public final int getSize()
                  throws java.lang.IllegalStateException,
                         CacheException
Gets the size of the cache. This is a subtle concept. See below.

The size is the number of Elements in the MemoryStore plus the number of Elements in the DiskStore.

This number is the actual number of elements, including expired elements that have not been removed.

Expired elements are removed from the the memory store when getting an expired element, or when attempting to spool an expired element to disk.

Expired elements are removed from the disk store when getting an expired element, or when the expiry thread runs, which is once every five minutes.

To get an exact size, which would exclude expired elements, use getKeysWithExpiryCheck().size(), although see that method for the approximate time that would take.

To get a very fast result, use getKeysNoDuplicateCheck().size(). If the disk store is being used, there will be some duplicates.

Returns:
The size value
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
CacheException

calculateInMemorySize

public final long calculateInMemorySize()
                                 throws java.lang.IllegalStateException,
                                        CacheException
Gets the size of the memory store for this cache

Warning: This method can be very expensive to run. Allow approximately 1 second per 1MB of entries. Running this method could create liveness problems because the object lock is held for a long period

Returns:
the approximate size of the memory store in bytes
Throws:
java.lang.IllegalStateException
CacheException

getMemoryStoreSize

public final long getMemoryStoreSize()
                              throws java.lang.IllegalStateException
Returns the number of elements in the memory store.

Returns:
the number of elements in the memory store
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

getDiskStoreSize

public final int getDiskStoreSize()
                           throws java.lang.IllegalStateException
Returns the number of elements in the disk store.

Returns:
the number of elements in the disk store.
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

getStatus

public final Status getStatus()
Gets the status attribute of the Cache.

Returns:
The status value from the Status enum class

getHitCount

public final int getHitCount()
                      throws java.lang.IllegalStateException
The number of times a requested item was found in the cache.

Returns:
the number of times a requested item was found in the cache
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

getMemoryStoreHitCount

public final int getMemoryStoreHitCount()
                                 throws java.lang.IllegalStateException
Number of times a requested item was found in the Memory Store.

Returns:
Number of times a requested item was found in the Memory Store.
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

getDiskStoreHitCount

public final int getDiskStoreHitCount()
                               throws java.lang.IllegalStateException
Number of times a requested item was found in the Disk Store.

Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

getMissCountNotFound

public final int getMissCountNotFound()
                               throws java.lang.IllegalStateException
Number of times a requested element was not found in the cache. This may be because it expired, in which case this will also be recorded in getMissCountExpired(), or because it was simply not there.

Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

getMissCountExpired

public final int getMissCountExpired()
                              throws java.lang.IllegalStateException
Number of times a requested element was found but was expired.

Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

getName

public final java.lang.String getName()
Gets the cache name.


setName

final void setName(java.lang.String name)
Sets the cache name which will name.

Parameters:
name - the name of the cache. Should not be null.

getTimeToIdleSeconds

public final long getTimeToIdleSeconds()
Gets timeToIdleSeconds.


getTimeToLiveSeconds

public final long getTimeToLiveSeconds()
Gets timeToLiveSeconds.


isEternal

public final boolean isEternal()
Are elements eternal.


isOverflowToDisk

public final boolean isOverflowToDisk()
Does the overflow go to disk.


getMaxElementsInMemory

public final int getMaxElementsInMemory()
Gets the maximum number of elements to hold in memory.


getMemoryStoreEvictionPolicy

public final MemoryStoreEvictionPolicy getMemoryStoreEvictionPolicy()
The policy used to evict elements from the MemoryStore. This can be one of:
  1. LRU - least recently used
  2. LFU - least frequently used
  3. FIFO - first in first out, the oldest element by creation time
The default value is LRU

Since:
1.2

toString

public final java.lang.String toString()
Returns a String representation of Cache.

Overrides:
toString in class java.lang.Object

isExpired

public final boolean isExpired(Element element)
                        throws java.lang.IllegalStateException,
                               java.lang.NullPointerException
Checks whether this cache element has expired.

The element is expired if:

  1. the idle time is non-zero and has elapsed, unless the cache is eternal; or
  2. the time to live is non-zero and has elapsed, unless the cache is eternal; or
  3. the value of the element is null.

Returns:
true if it has expired
Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE
java.lang.NullPointerException - if the element is null

clone

public final java.lang.Object clone()
                             throws java.lang.CloneNotSupportedException
Clones a cache. This is only legal if the cache has not been initialized. At that point only primitives have been set and no LruMemoryStore or DiskStore has been created.

A new, empty, RegisteredEventListeners is created on clone.

Overrides:
clone in class java.lang.Object
Returns:
an object of type Cache
Throws:
java.lang.CloneNotSupportedException

getDiskStore

final DiskStore getDiskStore()
                      throws java.lang.IllegalStateException
Gets the internal DiskStore.

Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

getMemoryStore

final MemoryStore getMemoryStore()
                          throws java.lang.IllegalStateException
Gets the internal MemoryStore.

Throws:
java.lang.IllegalStateException - if the cache is not Status.STATUS_ALIVE

isDiskPersistent

public final boolean isDiskPersistent()
Returns:
true if the cache overflows to disk and the disk is persistent between restarts

getDiskExpiryThreadIntervalSeconds

public final long getDiskExpiryThreadIntervalSeconds()
Returns:
the interval between runs of the expiry thread, where it checks the disk store for expired elements. It is not the the timeToLiveSeconds.

getCacheEventNotificationService

public final RegisteredEventListeners getCacheEventNotificationService()
Use this to access the service in order to register and unregister listeners

Returns:
the RegisteredEventListeners instance for this cache.

isElementInMemory

public final boolean isElementInMemory(java.io.Serializable key)
Whether an Element is stored in the cache in Memory, indicating a very low cost of retrieval.

Returns:
true if an element matching the key is found in memory

isElementInMemory

public final boolean isElementInMemory(java.lang.Object key)
Whether an Element is stored in the cache in Memory, indicating a very low cost of retrieval.

Returns:
true if an element matching the key is found in memory
Since:
1.2

isElementOnDisk

public final boolean isElementOnDisk(java.io.Serializable key)
Whether an Element is stored in the cache on Disk, indicating a higher cost of retrieval.

Returns:
true if an element matching the key is found in the diskStore

isElementOnDisk

public final boolean isElementOnDisk(java.lang.Object key)
Whether an Element is stored in the cache on Disk, indicating a higher cost of retrieval.

Returns:
true if an element matching the key is found in the diskStore
Since:
1.2

getGuid

public final java.lang.String getGuid()
The GUID for this cache instance can be used to determine whether two cache instance references are pointing to the same cache.

Returns:
the globally unique identifier for this cache instance. This is guaranteed to be unique.
Since:
1.2

getCacheManager

public final CacheManager getCacheManager()
Gets the CacheManager managing this cache. For a newly created cache this will be null until it has been added to a CacheManager.

Returns:
the manager or null if there is none

setCacheManager

final void setCacheManager(CacheManager cacheManager)
Package local setter for use by CacheManager

Parameters:
cacheManager -

ehcache