IdentityDictionary subclass:#PropertyListDictionary
	instanceVariableNames:''
	classVariableNames:''
	poolDictionaries:''
	category:'Interface-Support-UI'
!

!PropertyListDictionary class methodsFor:'documentation'!

documentation
"
    Instances are used temporarily by the UISpecification to keep dynamic
    properties for a view.
    For example, all the callbacks used by the drag & drop operation are
    stored.

    [author:]
        Claus Atzkern

    [see also:]
        UISpecification
"
! !

!PropertyListDictionary methodsFor:'accessing'!

at:aKey
    "returns the value stored under the key or nil
    "
    ^ self at:aKey ifAbsent:nil
!

dropSourceFor:aReceiver
    "returns the DropSource for a receiver or nil
    "
    |source|

    self canDrag ifTrue:[
        source := DropSource receiver:aReceiver
                             argument:(self at:#dragArgument:)
                   dropObjectSelector:(self at:#dropObjectSelector:)
                displayObjectSelector:(self at:#displayObjectSelector:)
                     feedBackSelector:(self at:#feedBackSelector:).

        source startDragSelector:(self at:#startDragSelector:).
        ^ source
    ].
    ^ nil
!

dropTargetFor:aReceiver
    "returns the DropTarget for a receiver or nil
    "
    |target|

    self canDrop ifTrue:[
        target := DropTarget receiver:aReceiver
                             argument:(self at:#dropArgument:)
                         dropSelector:(self at:#dropSelector:) 
                      canDropSelector:(self at:#canDropSelector:).

        target enterSelector:(self at:#enterSelector:).
        target  overSelector:(self at:#overSelector:).
        target leaveSelector:(self at:#leaveSelector:).
      ^ target
    ].
    ^ nil

! !

!PropertyListDictionary methodsFor:'building'!

actionSelectors
    "returns the list of action selectors 
    "
    |list|

    list := OrderedCollection new.

    self keysAndValuesDo:[:aKey :aVal|
        (aVal isSymbol and:[self isActionSelector:aKey]) ifTrue:[
            list add:aVal
        ]
    ].
    ^ list        
!

aspectSelectors
    "returns the list of aspect selectors or nil 
    "
    ^ nil        
! !

!PropertyListDictionary methodsFor:'converting'!

fromLiteralArrayEncoding:aLiteralEncodedArray
    "read my values from an encoding
    "
    |key val|

    2 to:aLiteralEncodedArray size by:2 do:[:i |
        key := aLiteralEncodedArray at:i.
        val := (aLiteralEncodedArray at:i+1) decodeAsLiteralArray.

        self at:key put:val
    ]

!

literalArrayEncoding
    "encode myself as an array, from which a copy of the receiver
     can be reconstructed with #decodeAsLiteralArray.
    "
    |coll|

    coll := OrderedCollection new.
    coll add:(self class name asSymbol).

    self keysAndValuesDo:[:aKey :aVal|
        coll add:aKey; add:(aVal literalArrayEncoding)
    ].
    ^ coll asArray

! !

!PropertyListDictionary methodsFor:'queries'!

canDrag
    "returns true if the receiver of the property list is draggable
    "
    ^ self includesKey:#dropObjectSelector:
!

canDrop
    "returns true if the receiver of the property list is droppable
    "
    ^ self includesKey:#dropSelector:
!

isActionSelector:aKey
    "returns true if the key is an action selector
    "
    ^ (     aKey ~~ #dragArgument:
       and:[aKey ~~ #dropArgument:]
      )
! !

!PropertyListDictionary class methodsFor:'documentation'!

version
    ^ '$Header: /cvs/stx/stx/libview2/PropertyListDictionary.st,v 1.1 1998-03-31 07:48:29 ca Exp $'
! !