Package com.mckoi.util
Class Cache
java.lang.Object
com.mckoi.util.Cache
Represents a cache of Objects. A Cache is similar to a Hashtable, in that
you can 'add' and 'get' objects from the container given some key. However
a cache may remove objects from the container when it becomes too full.
The cache scheme uses a doubly linked-list hashtable. The most recently accessed objects are moved to the start of the list. The end elements in the list are wiped if the cache becomes too full.
- Author:
- Tobias Downer
-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected void
This is called whenever at Object is put into the cache.protected final int
clean()
Cleans away some old elements in the cache.void
clear()
final Object
If the cache contains the cell with the given key, this method will return the object.protected final int
Deprecated.final int
Returns the number of nodes that are currently being stored in the cache.protected void
notifyGetWalks
(long total_walks, long total_get_ops) Notifies that some statistical information about the hash map has updated.protected void
Notifies that the given object has been wiped from the cache by the clean up procedure.final void
Puts an Object into the cache with the given key.final Object
Ensures that there is no cell with the given key in the cache.void
Clear the cache of all the entries.protected boolean
Returns true if the clean-up method that periodically cleans up the cache, should clean up more elements from the cache.
-
Constructor Details
-
Cache
public Cache(int hash_size, int max_size, int clean_percentage) The Constructors. It takes a maximum size the cache can grow to, and the percentage of the cache that is wiped when it becomes too full. -
Cache
public Cache(int max_size, int clean_percentage) -
Cache
public Cache(int max_size) -
Cache
public Cache()
-
-
Method Details
-
getHashSize
protected final int getHashSize()Deprecated.Creates the HashMap object to store objects in this cache. This is available to be overwritten. -
checkClean
protected void checkClean()This is called whenever at Object is put into the cache. This method should determine if the cache should be cleaned and call the clean method if appropriate. -
shouldWipeMoreNodes
protected boolean shouldWipeMoreNodes()Returns true if the clean-up method that periodically cleans up the cache, should clean up more elements from the cache. -
notifyWipingNode
Notifies that the given object has been wiped from the cache by the clean up procedure. -
notifyGetWalks
protected void notifyGetWalks(long total_walks, long total_get_ops) Notifies that some statistical information about the hash map has updated. This should be used to compile statistical information about the number of walks a 'get' operation takes to retreive an entry from the hash.This method is called every 8192 gets.
-
nodeCount
public final int nodeCount()Returns the number of nodes that are currently being stored in the cache. -
put
Puts an Object into the cache with the given key. -
get
If the cache contains the cell with the given key, this method will return the object. If the cell is not in the cache, it returns null. -
remove
Ensures that there is no cell with the given key in the cache. This is useful for ensuring the cache does not contain out-dated information. -
removeAll
public void removeAll()Clear the cache of all the entries. -
clear
public void clear() -
clean
protected final int clean()Cleans away some old elements in the cache. This method walks from the end, back 'wipe_count' elements putting each object on the recycle stack.
-