List subclass:#HierarchicalList

	instanceVariableNames:'root showRoot application monitoringTask monitoringTaskDelay'

	classVariableNames:''

	poolDictionaries:''

	category:'AAA-Model'

!

!HierarchicalList class methodsFor:'documentation'!

documentation

"

    Hierarchical Lists are mostly like List, but adding and removing

    elements are handled by the items itself.

    Special change notifications are emitted, whenever the list

    changed.

    [Instance variables:]

        root        <HierarchicalItem>  first item into list

        showRoot    <Boolean>           show or hide root item

        application <Application>       the user is able to set an application

                                        which can be accessed by an item.

    [author:]

        Claus Atzkern

    [see also:]

        HierarchicalItem

        HierarchicalListView

"

! !

!HierarchicalList methodsFor:'accessing look'!

showRoot

    "show or hide root item

    "

    ^ showRoot ? true

!

showRoot:aBoolean

    "show or hide root item

    "

    aBoolean ~~ self showRoot ifTrue:[

        showRoot := aBoolean.

        root notNil ifTrue:[

            showRoot ifTrue:[super addFirst:root]

                    ifFalse:[super removeFirst]

        ]

    ]

! !

!HierarchicalList methodsFor:'accessing monitoring task'!

monitoringTaskDelay

    "get the delay time of the monitoring task measured  in seconds

     or nil( monitoring disabled ). The task runs through all items 

     of the list performing #monitoringCycle and than at end of the

     list the task is suspended for monitoringTaskDelay seconds.

    "

    ^ monitoringTaskDelay

!

monitoringTaskDelay:inSecondsOrNil

    "set the delay time of the monitoring task measured  in seconds

     or nil( monitoring disabled ). The task runs through all items 

     of the list performing #monitoringCycle and than at end of the

     list the task is suspended for monitoringTaskDelay seconds.

    "

    monitoringTaskDelay := inSecondsOrNil.

    inSecondsOrNil isNil ifTrue:[

        self stopMonitoringTask

    ] ifFalse:[

        self startMonitoringTask

    ].

! !

!HierarchicalList methodsFor:'accessing mvc'!

application

    "returns the responsible application; if no application is defined,

     nil is returned

    "

    ^ application

!

application:anApplication

    "set the responsible application

    "

    application := anApplication

!

applicationsDo:aOneArgBlock

    "evaluate the block on each dependent application

    "

    |appl|

    dependents notNil ifTrue:[

        dependents do:[:aDep|

            appl := aDep perform:#application ifNotUnderstood:nil.

            appl notNil ifTrue:[

                aOneArgBlock value:appl

            ]

        ]

    ]

! !

!HierarchicalList methodsFor:'accessing root'!

root

    "get the root item

    "

    ^ root

!

root:aRoot

    "set the root item

    "

    |children monitoring|

    self stopMonitoringTask.

    root notNil ifTrue:[

        root parent:nil.

        root := nil.

        super removeAll.

    ].

    (root := aRoot) notNil ifTrue:[

        root parent:self.

        children := OrderedCollection new.

        self showRoot ifTrue:[children add:root].

        root addVisibleChildrenTo:children.

        super addAll:children beforeIndex:1

    ].

    self startMonitoringTask.

! !

!HierarchicalList methodsFor:'private'!

isHierarchicalItem

    "used to decide if the parent is a hierarchical item

     or the model

    "

    ^ false

!

itemAddAll:aListOfItems beforeIndex:anIndex

    "insert all items before an index

    "

    super addAll:aListOfItems beforeIndex:anIndex

!

itemChanged:what with:aPara from:anItem

    "catch notification from item; throw changeNotifications

     to dependencies;

     **** don't know what to do with a parameter and argument what

     **** list protocol ****

    "

    |index arrIdx "{ Class: SmallInteger }"|

    (index := super identityIndexOf:anItem) ~~ 0 ifTrue:[

        arrIdx := index + firstIndex - 1.

        contentsArray basicAt:arrIdx put:anItem.

        dependents size ~~ 0 ifTrue:[

            what isNil ifTrue:[self changed:#at: with:index]

                      ifFalse:[self changed:#at: with:(Array with:index with:what)]

        ]

    ]

!

itemRemoveFromIndex:start toIndex:stop

    "remove the items stored under startIndex up to and including

     the items under stopIndex.

    "

    ^ super removeFromIndex:start toIndex:stop

!

parentOrModel

    "always returns nil

    "

    ^ nil

! !

!HierarchicalList methodsFor:'private monitoring task'!

addDependent:anObject

    "restart the monitoringTask if neccessary

    "

    super addDependent:anObject.

    self  startMonitoringTask.

!

removeDependent:anObject

    "stop the monitoringTask if no more dependencies exists

    "

    super removeDependent:anObject.

    dependents size == 0 ifTrue:[

        self stopMonitoringTask

    ].

!

startMonitoringTask

    "start the monitoring task; success only if dependencies exists

    "

    |task|

    (     monitoringTask      isNil

     and:[monitoringTaskDelay notNil

     and:[dependents size ~~ 0]]

    ) ifTrue:[

        task := monitoringTask := [|index item delay|

            index := showRoot ifTrue:[1] ifFalse:[0].

            [true] whileTrue:[

                item := index == 0 ifTrue:[root]

                                  ifFalse:[self at:index ifAbsent:nil].

                item isNil ifTrue:[

                    delay := self monitoringTaskDelay.

                    delay isNil ifTrue:[                "/ process might terminate

                        task ~~ monitoringTask ifTrue:[

                            self terminate

                        ].

                        Processor yield

                    ] ifFalse:[

                        Delay waitForSeconds:delay.

                        task ~~ monitoringTask ifTrue:[ "/ task has changed

                            self terminate

                        ]

                    ].

                    index := showRoot ifTrue:[1] ifFalse:[0].

                ] ifFalse:[

                    item monitoringCycle.

                    Processor yield.

                    index := index + 1.

                ]

            ]

        ] forkAt:4.

    ].

    ^ true.

!

stopMonitoringTask

    "stop the monitoring task

    "

    |task|

    (task := monitoringTask) notNil ifTrue:[

        monitoringTask := nil.

        task terminate

    ]

! !

!HierarchicalList methodsFor:'protocol'!

childrenFor:anItem

    "returns the children for an item or an empty list

    "

    ^ #()

!

iconFor:anItem

    "returns the icon for an item or nil

    "

    ^ nil

!

labelFor:anItem

    "returns the label for an item or nil

    "

    ^ nil

!

middleButtonMenuFor:anItem

    "returns the middleButton menu for an item or nil

    "

    ^ nil

! !

!HierarchicalList class methodsFor:'documentation'!

version

    ^ '$Header: /cvs/stx/stx/libwidg2/HierarchicalList.st,v 1.1 1999-05-23 12:56:14 cg Exp $'

! !