TResourceCache

type TResourceCache = class

protected

  FItems: TAvlTree;

  FDescriptors: TAvlTree;

  FDestroying: Boolean;

FDestroying - local boolean variable to store Destroying status.

  FResourceCacheDescriptorClass: TResourceCacheDescriptorClass;

FResourceCacheDescriptorClass - local variable for holding the class of the current descriptor.

  FResourceCacheItemClass: TResourceCacheItemClass;

FResourceCacheItemClass - local variable for holding the class of the current cache item.

  FMaxUnusedItem: Integer;

FMaxUnusedItem - how many freed resources to keep.

  FFirstUnusedItem: TResourceCacheItem;

FFirstUnusedItem - local variable storing location of first free item.

  FLastUnusedItem: TResourceCacheItem;

FLastUnusedItem - local variable storing location of last free item.

  FUnUsedItemCount: Integer;

FUnUsedItemCount - local variable with count of free items.

  FLock: TCriticalSection;

  procedure RemoveItem(); virtual;

RemoveItem from CacheItem list.

  procedure RemoveDescriptor(); virtual;

RemoveDescriptor from Cache Descriptor list.

  procedure ItemUsed();

ItemUsed - method for signalling that the specified Item is being used.

  procedure ItemUnused();

ItemUnused - method for signalling that the specified Item is unused.

  function ItemIsUsed();

ItemIsUsed - returns True if specified Item is being used.

public

  constructor Create;

Constructor for the class instance.

  procedure Clear;

Clears the current entries in the Resource Cache.

  destructor Destroy; override;

Destructor for the class instance.

  function CompareItems(); virtual;

CompareItems - returns 0 if items are equal, -1 if Item1 is less, 1 if Item1 is greater.

  function CompareDescriptors(); virtual; abstract;

CompareDescriptors - returns 0 if descriptors are equal, -1 if Desc1 is less, 1 if Desc1 is greater.

  procedure ConsistencyCheck;

ConsistencyCheck - checks that Items have valid descriptors.

  procedure Lock;

  procedure Unlock;

  property MaxUnusedItem: Integer; [rw]

MaxUnusedItem - the largest permitted number of unused items.

  property ResourceCacheItemClass: TResourceCacheItemClass; [r]

ResourceCacheItemClass - the Class of the current Cache Item.

  property ResourceCacheDescriptorClass: TResourceCacheDescriptorClass; [r]

ResourceCacheDescriptorClass - the class of the current cache item descriptor.

end;

TResourceCache

TResourceCache - a cache (linked list) for storing Resources.

TObject