org.fujion.common

Class AbstractCache<KEY,VALUE>

java.lang.Object

org.fujion.common.AbstractCache<KEY,VALUE>

Type Parameters:

KEY - The class of the indexing key.

VALUE - The class of the cached item.

All Implemented Interfaces:

Iterable<VALUE>

public abstract class AbstractCache<KEY,VALUE>
extends Object
implements Iterable<VALUE>

Abstract class for managing globally cached data. Subclasses must implement the fetch logic for retrieving the data object into the cache.

Constructor Summary

Constructors

Constructor and Description
AbstractCache()

Method Summary

Modifier and Type	Method and Description
void	clear() Clear the cache of all entries.
protected abstract VALUE	fetch(KEY key) Logic to retrieve the data item from its primary store based on the provided key.
VALUE	get(KEY key) Get value for specified key.
boolean	isCached(KEY key) Returns true if the item associated with the specified key is in the cache.
Iterator<VALUE>	iterator() Iterate over value set.
void	refresh() Refresh the cache.
int	size() Return number of entries.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

AbstractCache

public AbstractCache()

Method Detail

fetch

protected abstract VALUE fetch(KEY key)

Logic to retrieve the data item from its primary store based on the provided key. The returned item will be stored in the cache for future retrieval. Note that it is acceptable to return a null item from this call.

Parameters:

key - The key.

Returns:

The fetched value.

get

public VALUE get(KEY key)

Get value for specified key. If not in cache, will call subclass's fetch method and load into cache.

Parameters:

key - The key.

Returns:

The associated value.

isCached

public boolean isCached(KEY key)

Returns true if the item associated with the specified key is in the cache.

Parameters:

key - The key.

Returns:

True if associated item has been cached.

refresh

public void refresh()

Refresh the cache. Any existing entries in the cache will be re-fetched after it is cleared.

clear

public void clear()

Clear the cache of all entries.

iterator

public Iterator<VALUE> iterator()

Iterate over value set.

Specified by:

iterator in interface Iterable<VALUE>

size

public int size()

Return number of entries.

Returns:

Number of entries.