uk.ac.ed.epcc.webapp.model.data

Class DataCache<K,V>

java.lang.Object

uk.ac.ed.epcc.webapp.model.data.DataCache<K,V>

Type Parameters:

K - type of key

V - type of data

Direct Known Subclasses:

IndexedDataCache, IndexedReferenceDataCache, LockedDataCache

public abstract class DataCache<K,V>
extends java.lang.Object

DataCache implements caches round queries that will be repeated multiple times, e.g. username lookups. It caches the results so later identical queries do no have to go to the DB Concrete subclasses will usually be inner classes of a Factory class

Constructor Summary

Constructors

Constructor and Description
DataCache()
DataCache(java.util.Map<K,V> initial_data)

Method Summary

Modifier and Type	Method and Description
java.util.Set<K>	badKeys()
void	clear()
protected abstract V	find(K key) The underlying query method.
V	get(K key) The public query method.
int	nBadKeys()
void	save(K key, V value) explicitly load data into the cache

Methods inherited from class java.lang.Object

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

Constructor Detail

DataCache

public DataCache()

DataCache

public DataCache(java.util.Map<K,V> initial_data)

Method Detail

find

protected abstract V find(K key)
                   throws DataException

The underlying query method.

Parameters:

key -

Returns:

Object from cache

Throws:

DataException

save

public void save(K key,
                 V value)

explicitly load data into the cache

Parameters:

key -

value -

get

public V get(K key)

The public query method. It looks up a result object and returns it. If the lookup fails to find a value it return null.

Parameters:

key -

Returns:

found Object or null for bad key

nBadKeys

public int nBadKeys()

badKeys

public java.util.Set<K> badKeys()

clear

public void clear()