"

 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.

"

       instanceVariableNames:'domain map'

       classVariableNames:''

       poolDictionaries:''

       category:'Collections-Ordered'

!

MappedCollection comment:'

COPYRIGHT (c) 1993 by Claus Gittinger

              All Rights Reserved

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. 

'!

!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

    ^ domain at:(map at:key)

!

at:key put:anObject

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

!

contents

    |contents|

    contents := Bag new.

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

    ^ contents

!

add:anObject

    self shouldNotImplement

! !

!MappedCollection methodsFor:'testing'!

size

    "return the number of elements in the receiver"

    ^ map size

! !

!MappedCollection methodsFor:'enumerating'!

do:aBlock

    "evaluate the argument, aBlock for each element"

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

!

collect:aBlock

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

     and return a new collection with the results"

    |newCollection|

    newCollection := self species new:self size.

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

    ^ newCollection

!

select:aBlock

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

     the argument aBlock evaluates to true"

    |newCollection|

    newCollection := self species 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

!

species

    ^ domain species

! !