Frank Shearar uploaded a new version of Collections to project The Trunk:
http://source.squeak.org/trunk/Collections-fbs.544.mcz

==================== Summary ====================

Name: Collections-fbs.544
Author: fbs
Time: 24 November 2013, 12:47:44.329 pm
UUID: 15771139-bae8-3347-8d63-a02d324e1e48
Ancestors: Collections-nice.543

Move LRUCache from System to Collections, because that's a more sensible home.

This also has the nice property that it breaks the Balloon->System dependency.

=============== Diff against Collections-nice.543 ===============

Item was changed:
  SystemOrganization addCategory: #'Collections-Abstract'!
  SystemOrganization addCategory: #'Collections-Arrayed'!
+ SystemOrganization addCategory: #'Collections-Cache'!
  SystemOrganization addCategory: #'Collections-Exceptions'!
  SystemOrganization addCategory: #'Collections-Sequenceable'!
  SystemOrganization addCategory: #'Collections-Stack'!
  SystemOrganization addCategory: #'Collections-Streams'!
  SystemOrganization addCategory: #'Collections-Strings'!
  SystemOrganization addCategory: #'Collections-Support'!
  SystemOrganization addCategory: #'Collections-Text'!
  SystemOrganization addCategory: #'Collections-Unordered'!
  SystemOrganization addCategory: #'Collections-Weak'!

Item was added:
+ Object subclass: #LRUCache
+ 	instanceVariableNames: 'size factory calls hits values'
+ 	classVariableNames: ''
+ 	poolDictionaries: ''
+ 	category: 'Collections-Cache'!
+ 
+ !LRUCache commentStamp: '<historical>' prior: 0!
+ I'm a cache of values, given a key I return a Value from the cache or from the factory!

Item was added:
+ ----- Method: LRUCache class>>size:factory: (in category 'instance creation') -----
+ size: aNumber factory: aBlock 
+ 	"answer an instance of the receiver"
+ 	^ self new initializeSize: aNumber factory: aBlock!

Item was added:
+ ----- Method: LRUCache class>>test (in category 'testing') -----
+ test
+ 	" 
+ 	LRUCache test 
+ 	"
+ 	| c |
+ 	c := LRUCache
+ 				size: 5
+ 				factory: [:key | key * 2].
+ 	c at: 1.
+ 	c at: 2.
+ 	c at: 3.
+ 	c at: 4.
+ 	c at: 1.
+ 	c at: 5.
+ 	c at: 6.
+ 	c at: 7.
+ 	c at: 8.
+ 	c at: 1.
+ 	^ c!

Item was added:
+ ----- Method: LRUCache class>>test2 (in category 'testing') -----
+ test2
+ 	" 
+ 	LRUCache test2.  
+ 	Time millisecondsToRun:[LRUCache test2]. 
+ 	MessageTally spyOn:[LRUCache test2].  
+ 	"
+ 	| c |
+ 	c := LRUCache
+ 				size: 600
+ 				factory: [:key | key * 2].
+ 	1
+ 		to: 6000
+ 		do: [:each | c at: each].
+ 	^ c!

Item was added:
+ ----- Method: LRUCache>>at: (in category 'accessing') -----
+ at: aKey 
+ 	"answer the object for aKey, if not present in the cache creates it"
+ 	| element keyHash |
+ 	calls := calls + 1.
+ 	keyHash := aKey hash.
+ 	1
+ 		to: size
+ 		do: [:index | 
+ 			element := values at: index.
+ 			(keyHash
+ 						= (element at: 2)
+ 					and: [aKey
+ 							= (element at: 1)])
+ 				ifTrue: ["Found!!"
+ 					hits := hits + 1.
+ 					values
+ 						replaceFrom: 2
+ 						to: index
+ 						with: (values first: index - 1).
+ 					values at: 1 put: element.
+ 					^ element at: 3]].
+ 	"Not found!!"
+ 	element := {aKey. keyHash. factory value: aKey}.
+ 	values
+ 		replaceFrom: 2
+ 		to: size
+ 		with: values allButLast.
+ 	values at: 1 put: element.
+ 	^ element at: 3!

Item was added:
+ ----- Method: LRUCache>>initializeSize:factory: (in category 'initialization') -----
+ initializeSize: aNumber factory: aBlock 
+ 	"initialize the receiver's size and factory"
+ 	size := aNumber.
+ 	values := Array new: aNumber withAll: {nil. nil. nil}.
+ 	factory := aBlock.
+ 	calls := 0.
+ 	hits := 0!

Item was added:
+ ----- Method: LRUCache>>printOn: (in category 'printing') -----
+ printOn: aStream 
+ 	"Append to the argument, aStream, a sequence of characters 
+ 	that identifies the receiver."
+ 	aStream nextPutAll: self class name;
+ 		 nextPutAll: ' size:';
+ 		 nextPutAll: size asString;
+ 		 nextPutAll: ', calls:';
+ 		 nextPutAll: calls asString;
+ 		 nextPutAll: ', hits:';
+ 		 nextPutAll: hits asString;
+ 		 nextPutAll: ', ratio:';
+ 		 nextPutAll: ((hits isNumber and: [calls isNumber and: [calls ~= 0]])
+ 			ifTrue: [hits / calls]
+ 			ifFalse: [0]) asFloat asString!