uk.ac.kcl.cch.jb.pliny.model
Class ResourceCache

java.lang.Object
  uk.ac.kcl.cch.rdb2java.dynData.Rdb2javaCache
      uk.ac.kcl.cch.jb.pliny.model.ResourceCache

public class ResourceCache

extends Rdb2javaCache

overrides the Rdb2javaCache used by other rdb2java managed objects to meet the special needs of the Resource class. These special needs are two:

1. The NoteLucened item is derived from the base Resource class and needs special handling so that if the item if fetched from its DB key only that a NoteLucened object is returned rather than a base Resource object.
2. Similarly, other Pliny related plugins can have their own derived version of the Resource class. The IResourceExtensionProcessor provides a method to request the generation of such a class that the rdb2java code can then fill with data, and ensures that the cache will return this class rather than the base Resource class.

The fact that this Resource is a special type needs to be indicated in the DB data -- and this task is managed by the reference to the ObjectType.

Author:

John Bradley

Field Summary

Fields inherited from class uk.ac.kcl.cch.rdb2java.dynData.Rdb2javaCache

myCache, myDataType

Constructor Summary

ResourceCache(IObjectFetcher myDataType)

Method Summary

Object	getItem(int key) this fetches a Resource when only the DB key for it is known.
Object	getItem(int key, int type) gets an item when both the DB key and the ObjectType associated with it is known.

Methods inherited from class uk.ac.kcl.cch.rdb2java.dynData.Rdb2javaCache

addNewItem, deleteItem

Methods inherited from class java.lang.Object

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

Constructor Detail

ResourceCache

public ResourceCache(IObjectFetcher myDataType)

Method Detail

getItem

public Object getItem(int key,
                      int type)

gets an item when both the DB key and the ObjectType associated with it is known. This will fetch the data from the NoteLucened cache if it is a Note type, will fetch the item from the cache if it is there, and if it is not will fetch the data from the DB (storing it in the cache), and using the object provided to it by IResourceExtensionProcessor.makeMyResource() if applicable.

Parameters:

key - DB key for the resource item.

type - type of item (key for the linked ObjectType.

Returns:

Resource-derived object with given key and type, or null if data for given key is not in the DB.

getItem

public Object getItem(int key)

this fetches a Resource when only the DB key for it is known. Note that if the Resource is a NoteLucened (has its ObjectType reference set as a Note) that this involves double read of the DB -- first to fetch it as a standard Resource, then, upon discovery that it is a Note, a second DB to get all the data for the NoteLucened version.

Overrides:

getItem in class Rdb2javaCache