org.craftercms.core.cache.impl

Class CacheImpl

java.lang.Object

org.craftercms.core.cache.impl.CacheImpl

All Implemented Interfaces:

Cache

public class CacheImpl
extends Object
implements Cache

Cache that implements common functionality, such as logging and expiration/refresh check every tick, and uses and underlying CacheStoreAdapter to store the items.

Author:

Sumer Jabri, Alfonso Vásquez

Field Summary

Fields

Modifier and Type	Field and Description
protected CacheRefresher	cacheRefresher Used to refresh a list of items.
protected CacheStoreAdapter	cacheStoreAdapter Adapter for the cache data structure.
protected AtomicInteger	ticks Holds the current number of ticks.

Constructor Summary

Constructors

Constructor and Description
CacheImpl() Default constructor.

Method Summary

Modifier and Type	Method and Description
void	addScope(String scope, int maxItemsInMemory) Adds a new scope to the cache.
protected boolean	checkForExpiration(CacheItem item) Checks if the given CacheItem has expired.
protected boolean	checkForRefresh(CacheItem item, List<CacheItem> itemsToRefresh) Checks if a given CacheItem needs to be refreshed.
void	clearAll() Clears the contents of the entire cache.
void	clearScope(String scope) Clears the contents of the specified scope in the cache.
protected void	doChecks(CacheItem item, List<CacheItem> itemsToRefresh) Checks if the given CacheItem has expired or needs to be refreshed.
CacheItem	get(String scope, Object key) Retrieves an item from a scope.
Collection<Object>	getKeys(String scope) Returns a list of the keys of the items present in the specified scope.
Collection<String>	getScopes() Returns the list of scopes this cache manages.
int	getSize(String scope) Returns the quantity of items present in the specified scope.
CacheStatistics	getStatistics(String scope) Returns the statistics of the specified scope in the cache.
boolean	hasKey(String scope, Object key) Returns true if there's and item with the specified key in the specified scope.
boolean	hasScope(String scope) Returns true if the specified scope exists in the cache.
void	put(String scope, Object key, Object value) Puts an item in a scope.
void	put(String scope, Object key, Object value, long expireAfter, long refreshFrequency, CacheLoader loader, Object... loaderParams) Puts and item in a scope.
boolean	remove(String scope, Object key) Removes an item from a scope.
void	removeScope(String scope) Removes an existing scope and all the items that are in it.
void	setCacheRefresher(CacheRefresher cacheRefresher) Sets the CacheRefresher, used to refresh the items of the cache.
void	setCacheStoreAdapter(CacheStoreAdapter cacheStoreAdapter) Sets the underlying CacheStoreAdapter
void	tick() Called when a tick occurs.

Methods inherited from class java.lang.Object

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

Field Detail

ticks

protected AtomicInteger ticks

Holds the current number of ticks.

cacheStoreAdapter

protected CacheStoreAdapter cacheStoreAdapter

Adapter for the cache data structure.

cacheRefresher

protected CacheRefresher cacheRefresher

Used to refresh a list of items.

Constructor Detail

CacheImpl

public CacheImpl()

Default constructor. Sets timestampGenerator to .IncrementalTimestampGenerator.

Method Detail

setCacheStoreAdapter

public void setCacheStoreAdapter(CacheStoreAdapter cacheStoreAdapter)

Sets the underlying CacheStoreAdapter

Parameters:

cacheStoreAdapter - the adapter for the cache data structure

setCacheRefresher

public void setCacheRefresher(CacheRefresher cacheRefresher)

Sets the CacheRefresher, used to refresh the items of the cache.

hasScope

public boolean hasScope(String scope)
                 throws InternalCacheEngineException

Returns true if the specified scope exists in the cache.

Specified by:

hasScope in interface Cache

Parameters:

scope - the name of the scope

Returns:

true if the specified scope exists in the cache

Throws:

InternalCacheEngineException - if an error occurred in the underlying cache implementation

getScopes

public Collection<String> getScopes()
                             throws InternalCacheEngineException

Returns the list of scopes this cache manages.

Specified by:

getScopes in interface Cache

Returns:

the list of available scopes in the cache

Throws:

InternalCacheEngineException - if an error occurred in the underlying cache implementation

addScope

public void addScope(String scope,
                     int maxItemsInMemory)
              throws InternalCacheEngineException

Adds a new scope to the cache.

Specified by:

addScope in interface Cache

Parameters:

scope - the name of the scope

maxItemsInMemory - the maximum number of items in memory, before they are evicted

Throws:

InternalCacheEngineException - if an error occurred in the underlying cache implementation

removeScope

public void removeScope(String scope)
                 throws InvalidScopeException,
                        InternalCacheEngineException

Removes an existing scope and all the items that are in it.

Specified by:

removeScope in interface Cache

Parameters:

scope - scope to remove

Throws:

InvalidScopeException - if the specified scope isn't a registered one

InternalCacheEngineException - if an error occurred in the underlying cache implementation

getSize

public int getSize(String scope)
            throws InvalidScopeException,
                   InternalCacheEngineException

Returns the quantity of items present in the specified scope.

Specified by:

getSize in interface Cache

Returns:

the size of the scope (quantity of items)

Throws:

InvalidScopeException - if the specified scope isn't a registered one

InternalCacheEngineException - if an error occurred in the underlying cache implementation

getKeys

public Collection<Object> getKeys(String scope)
                           throws InvalidScopeException,
                                  InternalCacheEngineException

Returns a list of the keys of the items present in the specified scope.

Specified by:

getKeys in interface Cache

Returns:

a list of the keys of the available items in the scope

Throws:

InvalidScopeException - if the specified scope isn't a registered one

InternalCacheEngineException - if an error occurred in the underlying cache implementation

hasKey

public boolean hasKey(String scope,
                      Object key)
               throws InvalidScopeException,
                      InternalCacheEngineException

Returns true if there's and item with the specified key in the specified scope.

Specified by:

hasKey in interface Cache

Returns:

true if the key exists in the scope, false otherwise

Throws:

InvalidScopeException - if the specified scope isn't a registered one

InternalCacheEngineException - if an error occurred in the underlying cache implementation

get

public CacheItem get(String scope,
                     Object key)
              throws InvalidScopeException,
                     InternalCacheEngineException

Retrieves an item from a scope.

Specified by:

get in interface Cache

Parameters:

scope - scope to get the item from

key - unique key for the item within this scope

Returns:

the requested item if found, null otherwise

Throws:

InvalidScopeException - if the specified scope isn't a registered one

InternalCacheEngineException - if an error occurred in the underlying cache implementation

put

public void put(String scope,
                Object key,
                Object value)
         throws InvalidScopeException,
                InternalCacheEngineException

Puts an item in a scope.

Specified by:

put in interface Cache

Parameters:

scope - scope to add the item to

key - unique key for the item within this scope

value - value to store in the cache

Throws:

InvalidScopeException - if the specified scope isn't a registered one

InternalCacheEngineException - if an error occurred in the underlying cache implementation

put

public void put(String scope,
                Object key,
                Object value,
                long expireAfter,
                long refreshFrequency,
                CacheLoader loader,
                Object... loaderParams)
         throws InvalidScopeException,
                InternalCacheEngineException

Puts and item in a scope.

Specified by:

put in interface Cache

Parameters:

scope - scope to add the item to

key - unique key for the item within this scope

value - value to store in the cache

expireAfter - the amount of time (in ticks, where the tick time span is defined at runtime) before the item can be removed from cache. Use CacheItem.NEVER_EXPIRE to indicate that there's no expiration time.

refreshFrequency - the amount of time (in ticks, where the tick time span is defined at runtime) before items are reloaded into the cache. Use CacheItem.NEVER_REFRESH to indicate that there's no need for the item to be refreshed. Note that when refreshing, there's almost always an old value for the item in the cache before the new value is loaded into the cache. The loader param is also required in order for the item to be refreshed.

loader - the cache loader used to load a new value when the item needs to be refreshed. If not specified and the refreshFrequency is not CacheItem.NEVER_REFRESH, the cache will use a default one.

loaderParams - additional parameters the loader could need

Throws:

InvalidScopeException - if the specified scope isn't a registered one

InternalCacheEngineException - if an error occurred in the underlying cache implementation

remove

public boolean remove(String scope,
                      Object key)
               throws InvalidScopeException,
                      InternalCacheEngineException

Removes an item from a scope.

Specified by:

remove in interface Cache

Parameters:

scope - scope to remove the item from

key - unique key for the item within this scope

Returns:

true if the removal was successful, false otherwise

Throws:

InvalidScopeException - if the specified scope isn't a registered one

InternalCacheEngineException - if an error occurred in the underlying cache implementation

clearAll

public void clearAll()
              throws InternalCacheEngineException

Clears the contents of the entire cache.

Specified by:

clearAll in interface Cache

Throws:

InternalCacheEngineException - if an error occurred in the underlying cache implementation

clearScope

public void clearScope(String scope)
                throws InvalidScopeException,
                       InternalCacheEngineException

Clears the contents of the specified scope in the cache.

Specified by:

clearScope in interface Cache

Parameters:

scope - scope to clear

Throws:

InvalidScopeException - if the specified scope isn't a registered one

InternalCacheEngineException - if an error occurred in the underlying cache implementation

getStatistics

public CacheStatistics getStatistics(String scope)

Returns the statistics of the specified scope in the cache.

Specified by:

getStatistics in interface Cache

Parameters:

scope - scope to inspect

Returns:

the statistics

tick

public void tick()

Called when a tick occurs. A tick is a logical unit of time. It basically symbolizes the time span between calls to this method (i.e. 15 mins) by a job scheduler like Quartz.

Checks if some of the CacheItems in the cache have expired or need to be refreshed. If the item has expired, it is removed from the cache. If it needs to be refreshed, it is added to a list of items that need to be refreshed that is later passed to the CacheRefresher.

doChecks

protected void doChecks(CacheItem item,
                        List<CacheItem> itemsToRefresh)

Checks if the given CacheItem has expired or needs to be refreshed.

Parameters:

item -

itemsToRefresh - the list of items where to put the specified item if it needs to be refreshed

checkForExpiration

protected boolean checkForExpiration(CacheItem item)
                              throws Exception

Checks if the given CacheItem has expired. If so, it is removed from its scope in the CacheStoreAdapter.

Returns:

true if the item has expired and was removed from the scope, false otherwise

Throws:

Exception

checkForRefresh

protected boolean checkForRefresh(CacheItem item,
                                  List<CacheItem> itemsToRefresh)

Checks if a given CacheItem needs to be refreshed. If so, then it is added to the listen of items to refresh.

Parameters:

item -

itemsToRefresh - the list of items where to put the specified item if it needs to be refreshed

Returns:

true if the item will be refreshed, false otherwise