"

 COPYRIGHT (c) 1993 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.

"

"{ Package: 'stx:libbasic2' }"

"{ NameSpace: Smalltalk }"

Collection subclass:#MappedCollection

	instanceVariableNames:'domain map'

	classVariableNames:''

	poolDictionaries:''

	category:'Collections-Sequenceable'

!

!MappedCollection class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1993 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

"

    MappedCollections represent collections of objects that are indirectly indexed by names.

    There are really two collections involved: domain and a map.  The map maps

    between external names and indices into domain, which contains the

    real association.  In order to work properly, the domain and map objects must

    be instances of a subclass of SequenceableCollection or Dictionary. 

    [author:]

        Claus Gittinger

"

!

examples

"

                                            [exBegin]

    |mapped dict|

    dict := Dictionary new

                at:'uno' put:1;

                at:'due' put:2;

                at:'tre' put:3;

                at:'quattro' put:4;

                yourself.

    mapped := MappedCollection

                    collection:#(one two three four)

                    map:dict.

    mapped at:'tre'.

    mapped select:[:each| each ~= 'two']

"

! !

!MappedCollection class methodsFor:'instance creation'!

collection:domainCollection map:mapCollection

    "return a new MappedCollection"

    ^ super new setCollection:domainCollection map:mapCollection

!

new

    "report an error; mappedCollections may not be created using new"

    self error:'use collection:map: to create a MappedCollection'

! !

!MappedCollection methodsFor:'accessing'!

at:key

    "retrieve an element"

    ^ domain at:(map at:key)

    "Modified: 2.8.1996 / 21:04:01 / cg"

!

at:key put:anObject

    "store an element"

    ^ domain at:(map at:key) put:anObject

    "Modified: 2.8.1996 / 21:04:06 / cg"

!

contents

    "return the contents as a bag"

    |contents|

    contents := Bag new.

    map do:[:key | contents add:(domain at:key)].

    ^ contents

    "Modified: 2.8.1996 / 21:04:10 / cg"

! !

!MappedCollection methodsFor:'adding & removing'!

add:anObject

    "report an error; mappedCollections cannot add elements (without a key)"

    self shouldNotImplement

    "Modified: 2.8.1996 / 21:03:57 / cg"

! !

!MappedCollection methodsFor:'copying'!

postCopy

    domain := domain copy.

    map := map copy

! !

!MappedCollection methodsFor:'enumerating'!

collect:aBlock

    "for each element in the receiver, evaluate the argument, aBlock

     and return a new collection with the results"

    |newCollection|

    newCollection := self speciesForAdding new:self size.

    self do:[:each | newCollection add:(aBlock value:each)].

    ^ newCollection

!

do:aBlock

    "evaluate the argument, aBlock for each element"

    map do:[:mapValue | aBlock value:(domain at:mapValue)].

!

select:aBlock

    "return a new collection with all elements from the receiver, for which

     the argument aBlock evaluates to true"

    |newCollection|

    newCollection := self speciesForAdding new:self size.

    self do:[:each |

        (aBlock value:each) ifTrue:[newCollection add:each].

    ].

    ^ newCollection

! !

!MappedCollection methodsFor:'private'!

setCollection:domainCollection map:mapCollection

    domain := domainCollection.

    map := mapCollection

! !

!MappedCollection methodsFor:'queries'!

isFixedSize

    "return true if the receiver cannot grow"

    ^ false

!

size

    "return the number of elements in the receiver"

    ^ map size

!

species

    "return the type of collection to be returned by collect, select etc."

    ^ domain species

!

speciesForAdding

    "like species, but redefined for collections which cannot grow easily.

     Used by functions which create a growing collection 

     (see collect:with:, for example)"

    ^ domain speciesForAdding

! !

!MappedCollection class methodsFor:'documentation'!

version

    ^ '$Header$'

! !