"{ Package: 'stx:libview2' }"

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 1.2 2001-02-06 18:49:24 ps Exp $'

! !