CollectionsCollectionCollection as an Abstract ClassSlide 4Abstract class as typeFinding an elementFind an ElementTransform a CollectionNonuniform Collection ProtocolCollection ProtocolsCollection MenagerieSlide 12OrderedCollectionSlide 14OC::do:OC::add:Slide 17Using OrderedCollections(continued)IntervalSlide 21Interval do:Slide 23Interval at:Interval at:put:SetHashClassic Set BugsSequenceableCollectionSlide 30Set bugsSet do:Set includes:Slide 34PowerPoint PresentationClassic Collection BugsConclusionCollectionsInheritancePolymorphismObject-oriented Programming and Design - Johnson & Yoder - Day 32Collection74 subclasses of Collection in Squeak 3.10Some are abstractSequenceableCollectionArrayedCollectionMost are concrete - Array, Bag, Dictionary, Interval, String, Set, SymbolObject-oriented Programming and Design - Johnson & Yoder - Day 33Collection as an Abstract ClassCollection has no instance variables.Collection defines as subclassResponsibilitydo:add:, remove: (Changeable)at:, at:put: (Sequenceable)Object-oriented Programming and Design - Johnson & Yoder - Day 34Collection as an Abstract ClassTemplate methods defined in terms of do:select:, collect:, inject:into:, detect:ifAbsent:, sizeObject-oriented Programming and Design - Johnson & Yoder - Day 35Abstract class as typeAll collections understand same protocoldo: iterateselect: subcollectioncollect: transformed collectioninject:into: reduce collection to valueincludes: does receiver contain it?detect: find an elementObject-oriented Programming and Design - Johnson & Yoder - Day 36Finding an elementnumbers do: [:each | each isOdd ifTrue: [^firstOdd := each]].… firstOdd ... numbers do: [:each | each isOdd ifTrue: [firstOdd ifNil ifTrue: [firstOdd := each]]]firstOdd := numbers detect: [:each | each isOdd]Object-oriented Programming and Design - Johnson & Yoder - Day 37Find an Elementdetect: aBlock ifNone: exceptionBlock "Evaluate aBlock with each of the receiver's elements as the argument. Answer the first element for which aBlock evaluates to true."self do: [:each | (aBlock value: each) ifTrue: [^each]].^exceptionBlock valueObject-oriented Programming and Design - Johnson & Yoder - Day 38Transform a Collectioncollect: aBlock | newCollection |newCollection := self species new.self do: [:each | newCollection add: (aBlock value: each)].^newCollectionObject-oriented Programming and Design - Johnson & Yoder - Day 39Nonuniform Collection Protocoladd: and remove: are defined by collections whose size can change---Set, OrderedCollection, Bag, etc.ArrayedCollection and Interval do not implement add: and remove:at: and at:put: are defined by SequenceableCollection and Dictionary, but not by Set or Bag.Object-oriented Programming and Design - Johnson & Yoder - Day 310Collection ProtocolsCollection do:, size, select:, collect:, inject:into:, includes:, detect:ChangeableCollection add: addAll: remove: removeAll:SequenceableCollection at: at:put first last , copyFrom:to:Object-oriented Programming and Design - Johnson & Yoder - Day 311Collection MenagerieArray, StringSeq.SymbolSeq., read-only, uniqueOrderedCollectionSeq., Changeable., a sequenceSet, BagChangeableObject-oriented Programming and Design - Johnson & Yoder - Day 312Collection MenagerieDictionaryat: and at:put: with any object as keyIntervalSeq., numeric, read-onlyRunArraySeq., compact encodingObject-oriented Programming and Design - Johnson & Yoder - Day 313OrderedCollectionInstance variables:Instance variables:firstIndex, lastIndexfirstIndex, lastIndexA changeable sequenceable collection.A changeable sequenceable collection.Supports add:, remove:, at:, at:put:Supports add:, remove:, at:, at:put:Object-oriented Programming and Design - Johnson & Yoder - Day 314OrderedCollectionat: anInteger anInteger isInteger ifFalse: [ ^...].(anInteger < 1 or: [anInteger + firstIndex - 1 > lastIndex])ifTrue: [^...]^ super at: anInteger + firstIndex - 1Object-oriented Programming and Design - Johnson & Yoder - Day 315OC::do:do: aBlock firstIndex to: lastIndex do: [:index | aBlock value: (self basicAt: index)].size^ lastIndex - firstIndex + 1Object-oriented Programming and Design - Johnson & Yoder - Day 316OC::add:add: newObject "Include newObject as one of the receiver's elements. Answer newObject."^ self addLast: newObjectObject-oriented Programming and Design - Johnson & Yoder - Day 317OC::add:addLast: newObject "Add newObject to the end of the receiver. Answer newObject."lastIndex = self basicSize ifTrue: [self makeRoomAtLast].lastIndex  lastIndex + 1.self basicAt: lastIndex put: newObject.^ newObjectObject-oriented Programming and Design - Johnson & Yoder - Day 318Using OrderedCollectionsSuppose that list is an ordered collection. We want newList to be the reverse of list.solution 1newList := OrderedCollection new.list do: [:each | newList addFirst: each]Object-oriented Programming and Design - Johnson & Yoder - Day 319(continued)solution 2newList := OrderedCollection newWithSize: list size.index := list size.list do: [:each | newList at: index put: each. index := index - 1]Object-oriented Programming and Design - Johnson & Yoder - Day 320IntervalInstance variables: start, stop, step1 to: 10001 to: 1000 by: 31 to: 1000 do: [:each | sum  sum + each]Object-oriented Programming and Design - Johnson & Yoder - Day 321IntervalNumberto: stop^ Interval from: self to: stop by: 1Object-oriented Programming and Design - Johnson & Yoder - Day 322Interval do:do: aBlock | n end |n := 0.end := self size - 1.[n <= end]whileTrue: [aBlock value: start + (step * n).n := n + 1]Object-oriented Programming and Design - Johnson & Yoder - Day 323Interval do:do: aBlock| aValue |aValue := start.step < 0ifTrue: [[stop <= aValue]whileTrue: [aBlock value: aValue.aValue := aValue + step]]ifFalse: [[stop >= aValue]whileTrue: [aBlock value: aValue.aValue := aValue + step]]Object-oriented Programming and Design - Johnson & Yoder - Day 324Interval at:at: anInteger (anInteger >= 1 and: [anInteger <= self size])ifTrue: [^start + (step * (anInteger - 1))]ifFalse: [^self subscriptBoundsError: anInteger]Object-oriented Programming and Design - Johnson & Yoder - Day 325Interval at:put:at: anInteger put: anObject "Provide an error notification that storing into an Interval is not allowed. "self error: 'you can not store into an interval'Object-oriented Programming and Design - Johnson & Yoder - Day 326SetA hash table. nil means an unused entry.Instance variables: tally3 19