"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

Object subclass:#Collection

	instanceVariableNames:''

	classVariableNames:'InvalidKeySignal EmptyCollectionSignal ValueNotFoundSignal

		NotEnoughElementsSignal'

	poolDictionaries:''

	category:'Collections-Abstract'

!

!Collection class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    Abstract superclass for all collections.

    This abstract class provides functionality common to all collections,

    without knowing how the concrete class implements things. Thus, all

    methods found here depend on some basic mechanisms to be defined in the

    concrete class. 

    These basic methods are usually defined as #subclassResponsibility here.

    Some methods are also redefined for better performance.

    [author:]

        Claus Gittinger

"

! !

!Collection class methodsFor:'initialization'!

initialize

    "setup the signal"

    InvalidKeySignal isNil ifTrue:[

	InvalidKeySignal := ErrorSignal newSignalMayProceed:true.

	InvalidKeySignal nameClass:self message:#invalidKeySignal.

	InvalidKeySignal notifierString:'invalid key:'.

	ValueNotFoundSignal := ErrorSignal newSignalMayProceed:true.

	ValueNotFoundSignal nameClass:self message:#valueNotFoundSignal.

	ValueNotFoundSignal notifierString:'value not found:'.

	NotEnoughElementsSignal := ErrorSignal newSignalMayProceed:true.

	NotEnoughElementsSignal nameClass:self message:#notEnoughElementsSignal.

	NotEnoughElementsSignal notifierString:'not enough elements in collection'.

	EmptyCollectionSignal := NotEnoughElementsSignal newSignalMayProceed:true.

	EmptyCollectionSignal nameClass:self message:#emptyCollectionSignal.

	EmptyCollectionSignal notifierString:'operation not allowed for empty collections'.

    ]

! !

!Collection class methodsFor:'instance creation'!

new:size withAll:element

    "return a new COllection of size, where all elements are

     initialized to element"

    |newCollection|

    newCollection := self new:size.

    size timesRepeat:[newCollection add:element]

!

with:anObject

    "return a new Collection with one element:anObject"

    |newCollection|

    newCollection := self new.

    newCollection add:anObject.

    ^ newCollection

!

with:firstObject with:secondObject

    "return a new Collection with two elements:firstObject and secondObject"

    |newCollection|

    newCollection := self new.

    newCollection add:firstObject; add:secondObject.

    ^ newCollection

!

with:firstObject with:secondObject with:thirdObject

    "return a new Collection with three elements"

    |newCollection|

    newCollection := self new.

    newCollection add:firstObject; add:secondObject; add:thirdObject.

    ^ newCollection

!

with:firstObject with:secondObject with:thirdObject with:fourthObject

    "return a new Collection with four elements"

    |newCollection|

    newCollection := self new.

    newCollection add:firstObject; add:secondObject; add:thirdObject; add:fourthObject.

    ^ newCollection

!

with:one with:two with:three with:four with:five

    "return a new Collection with five elements"

    |newCollection|

    newCollection := self new.

    newCollection add:one; add:two; add:three; add:four; add:five.

    ^ newCollection

!

withAll:aCollection

    "return a new Collection with all elements taken from the argument,

     aCollection"

    |newCollection|

    newCollection := self new.

    newCollection addAll:aCollection.

    ^newCollection

! !

!Collection class methodsFor:'Signal constants'!

emptyCollectionSignal

    "return the signal used to report non-allowed operation on empty collections"

    ^ EmptyCollectionSignal

!

invalidKeySignal

    "return the signal used to report bad key usage"

    ^ InvalidKeySignal

!

notEnoughElementsSignal

    "return the signal used to report attempts for an operation, for which

     there are not enough elements in the collection"

    ^ NotEnoughElementsSignal

!

valueNotFoundSignal

    "return the signal used to report a nonexisting element."

    ^ ValueNotFoundSignal

! !

!Collection class methodsFor:'queries'!

growIsCheap

    "return true, if this collection can easily grow

     (i.e. without a need for become:).

     Returns true here; this method is redefined in fix-size

     collections"

    ^ true

! !

!Collection methodsFor:'accessing'!

anElement

    "return any element from the collection, or nil if there is none"

    self do: [:each | ^ each].

    ^ nil

!

first

    "return the first element of the collection.

     This should be redefined in subclasses."

    self do:[:e | ^ e].

    "error if collection is empty"

    ^ self emptyCollectionError

!

firstIfEmpty:exceptionValue

    "return the first element of the collection.

     If its empty, return the excveptionValue.

     (i.e. dont trigger an error as done in #first)"

    self isEmpty ifTrue:[^ exceptionValue value].

    ^ self first

    "Modified: 6.2.1996 / 15:27:17 / cg"

!

last

    "return the last element of the collection.

     This should be redefined in subclasses."

    |theLastOne any|

    any := false.

    self do:[:e | any := true. theLastOne := e].

    any ifTrue:[

	^ theLastOne

    ].

    "error if collection is empty"

    ^ self emptyCollectionError

!

lastIfEmpty:exceptionValue

    "return the last element of the collection.

     If its empty, return the exceptionValue.

     (i.e. dont trigger an error as done in #last)"

    self isEmpty ifTrue:[^ exceptionValue value].

    ^ self last

    "Modified: 6.2.1996 / 15:27:17 / cg"

    "Created: 6.2.1996 / 15:27:49 / cg"

!

upTo:anElement

    "return a new collection consisting of the receivers elements upTo

     (but excluding) anElement.

     If anElement is not in the receiver, the returned collection

     will consist of all elements of the receiver"

    |s|

    s := ReadStream on:self.

    ^ s upTo:anElement

    "

     'test.text' upTo:$.  

     #(1 2 3 4 5) upTo:4  

    "

! !

!Collection methodsFor:'adding & removing'!

add:anObject

    "add the argument, anObject to the receiver.

     If the receiver is ordered, the position of the new element is undefined

     (i.e. dont depend on where it will be put)."

    ^ self subclassResponsibility

!

addAll:aCollection

    "add all elements of the argument, aCollection to the receiver.

     Returns the argument, aCollection."

    aCollection do:[:element |

        self add:element

    ].

    ^ aCollection

    "

     #(1 2 3 4) copy addAll:#(5 6 7 8)

     #(1 2 3 4) asOrderedCollection addAll:#(5 6 7 8)

    "

    "Modified: 12.4.1996 / 13:29:20 / cg"

!

addAllFirst:aCollection

    "insert all elements of the argument, aCollection at the beginning

     of the receiver. Returns the argument, aCollection."

    aCollection reverseDo:[:element | 

        self addFirst:element 

    ].

    ^ aCollection

    "

     |c|

     c := #(4 3 2 1) asOrderedCollection.

     c addAllFirst:#(9 8 7 6 5).

     c   

    "

    "Modified: 12.4.1996 / 13:30:10 / cg"

!

addAllLast:aCollection

    "add all elements of the argument, aCollection to the receiver.

     Returns the argument, aCollection."

    aCollection do:[:element | 

        self addLast:element 

    ].

    ^ aCollection

    "

     |c|

     c := #(4 3 2 1) asOrderedCollection.

     c addAllLast:#(9 8 7 6 5)

    "

    "Modified: 12.4.1996 / 13:30:54 / cg"

!

addFirst:anObject

    "add the argument, anObject to the receiver.

     If the receiver is ordered, the new element will be added at the beginning."

    ^ self subclassResponsibility

!

addLast:anObject

    "add the argument, anObject to the receiver. 

     If the receiver is ordered, the new element will be added at the end.

     Return the argument, anObject."

    ^ self add:anObject

    "Modified: 12.4.1996 / 13:31:12 / cg"

!

remove:anObject

    "remove the (first occurrence of) argument, anObject from the receiver,

     and return it.

     If it was not in the collection, raise an error."

    ^ self remove:anObject ifAbsent:[self errorValueNotFound:anObject]

    "Modified: 12.4.1996 / 13:33:30 / cg"

!

remove:anObject ifAbsent:exceptionBlock

    "remove the (first occurrence of) argument, anObject from the receiver,

     and return it.

     If it was not in the collection, return the the value of the exceptionBlock"

    ^ self subclassResponsibility

!

removeAll

    "remove all elements from the receiver. Returns the receiver.

     This should be reimplemented in subclasses for better

     performance."

    [self notEmpty] whileTrue:[

        self removeFirst

    ].

    "Modified: 12.4.1996 / 13:34:39 / cg"

!

removeAll:aCollection

    "remove all elements of the argument, aCollection from the receiver.

     Return the argument, aCollection.

     Notice: for some collections (those not tuned for

             resizing themself) this may be very slow.

             If the number of removed elements is big compared to to

             the receivers size, it may be better to copy the

             ones which are not to be removed into a new collection."

    aCollection do:[:element | self remove:element].

    ^ aCollection

    "Modified: 12.4.1996 / 13:35:48 / cg"

!

removeFirst

    "remove the first element from the receiver.

     Return the removed element."

    ^ self subclassResponsibility

!

removeFirst:n

    "remove the first n elements from the receiver.

     Return an array filled with the removed elements.

     Notice: for some collections (those not tuned for

	     resizing themself) this may be very slow."

    |ret|

    self size < n ifTrue:[

	^ self notEnoughElementsError

    ].

    ret := Array new:n.

    1 to:n do:[:i |

	ret at:i put:(self removeFirst).

    ].

    ^ ret

!

removeLast

    "remove the last element from the receiver.

     Return the removed element."

    ^ self subclassResponsibility

!

removeLast:n

    "remove the last n elements from the receiver.

     Return an array filled with the removed elements.

     Notice: for some collections (those not tuned for

	     resizing themself) this may be very slow."

    |ret|

    self size < n ifTrue:[

	^ self notEnoughElementsError

    ].

    ret := Array new:n.

    n to:1 by:-1 do:[:i |

	ret at:i put:(self removeLast).

    ].

    ^ ret

! !

!Collection methodsFor:'converting'!

asArray

    "return a new Array with the collections elements"

    |anArray 

     index "{ Class: SmallInteger }" |

    anArray := Array new:(self size).

    index := 1.

    self do:[:each |

	anArray at:index put:each.

	index := index + 1

    ].

    ^ anArray

!

asBag

    "return a new Bag with the receiver collections elements"

    ^ self addAllTo:(Bag new)

!

asByteArray

    "return a new ByteArray with the collections elements

     (which must convert to integers in the range 0..255)."

    |aByteArray 

     index "{ Class: SmallInteger }" |

    aByteArray := ByteArray new:(self size).

    index := 1.

    self do:[:each |

	aByteArray at:index put:each asInteger.

	index := index + 1

    ].

    ^ aByteArray

!

asDoubleArray