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

Class CachedIndexedProducer<T extends Indexed>

java.lang.Object

uk.ac.ed.epcc.webapp.model.data.CachedIndexedProducer<T>

Type Parameters:

T -

All Implemented Interfaces:

TypeConverter<T,java.lang.Number>, IndexedProducer<T>, Targetted<T>

public class CachedIndexedProducer<T extends Indexed>
extends java.lang.Object
implements IndexedProducer<T>

Decorator around a IndexProducer that caches values. The entire cache is hidden behind a SoftReference so if memory becomes tight the cache is cleared. This has less overhead than hiding individual elements behind a reference but it means we clear the entire cache if memory becomes tight.

Constructor Summary

Constructors

Constructor and Description
CachedIndexedProducer(IndexedProducer<T> m)

Method Summary

Modifier and Type	Method and Description
void	clear()
T	find(int id)
T	find(java.lang.Number o) Find the required object.
java.lang.String	getID(T obj) Generate the default text identifier of the client object for contexts where the type is unambiguous.
java.lang.Number	getIndex(T value) Get the underlying data representation corresponding to the value
java.lang.Class<T>	getTarget() Get a class object that all results of the producer are assignable to.
boolean	isMyReference(IndexedReference ref) Test if an IndexedReference belongs to this producer.
IndexedReference<T>	makeReference(int id) Make and IndexedReferencce from an integer id.
IndexedReference<T>	makeReference(T obj) Make a IndexedReference from a target object

Methods inherited from class java.lang.Object

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

Constructor Detail

CachedIndexedProducer

public CachedIndexedProducer(IndexedProducer<T> m)

Method Detail

find

public T find(int id)
       throws DataException

Specified by:

find in interface IndexedProducer<T extends Indexed>

Throws:

DataException

clear

public void clear()

getTarget

public java.lang.Class<T> getTarget()

Description copied from interface: IndexedProducer

Get a class object that all results of the producer are assignable to. This is intended for run-time type checking so it should be as specific as possible

Specified by:

getTarget in interface IndexedProducer<T extends Indexed>

Specified by:

getTarget in interface Targetted<T extends Indexed>

Returns:

Class object for target

makeReference

public IndexedReference<T> makeReference(T obj)

Description copied from interface: IndexedProducer

Make a IndexedReference from a target object

Specified by:

makeReference in interface IndexedProducer<T extends Indexed>

Returns:

IndexedReference

makeReference

public IndexedReference<T> makeReference(int id)

Description copied from interface: IndexedProducer

Make and IndexedReferencce from an integer id.

Specified by:

makeReference in interface IndexedProducer<T extends Indexed>

Returns:

IndexedReference

isMyReference

public boolean isMyReference(IndexedReference ref)

Description copied from interface: IndexedProducer

Test if an IndexedReference belongs to this producer. This returns false for any null reference.

Specified by:

isMyReference in interface IndexedProducer<T extends Indexed>

Returns:

boolean

find

public T find(java.lang.Number o)

Description copied from interface: TypeConverter

Find the required object.

Specified by:

find in interface TypeConverter<T extends Indexed,java.lang.Number>

Parameters:

o - Value of the database field

Returns:

Target value or null if invalid

getIndex

public java.lang.Number getIndex(T value)

Description copied from interface: TypeConverter

Get the underlying data representation corresponding to the value

Specified by:

getIndex in interface TypeConverter<T extends Indexed,java.lang.Number>

Returns:

Field value or null if invalid

getID

public java.lang.String getID(T obj)

Description copied from interface: IndexedProducer

Generate the default text identifier of the client object for contexts where the type is unambiguous. This is used in urls and html inputs. Normally this should generate the String representation of the integer id. if it generates anything else the IndexedProducer should implement ParseFactory to be able to parse the alternative form.

Specified by:

getID in interface IndexedProducer<T extends Indexed>

Returns: