_MAKING SMALLTALK WITH WIDGETS_
by Kenneth E. Ayers

[LISTING ONE]

"The Appointment class definition"

Object subclass: #Appointment
  instanceVariableNames: 
    'user date startTime endTime notifyTime text '
  classVariableNames: ''
  poolDictionaries: ''

"****  Appointment class methods  ****"
timePrintString:aTime
        "Answer a string with a representation of
         aTime formatted as hh:mm AM/PM"

    | amPM hours minutes minStr |

    amPM := 'AM'.
    hours := aTime hours.
    minutes := aTime minutes.
    hours = 0
        ifTrue: [hours := 12.  amPM := 'PM']
        ifFalse:[
            hours >= 12
                ifTrue:[
                    amPM := 'PM'.
                    hours > 12
                        ifTrue:[hours := hours - 12]]].
    minutes < 10
        ifTrue: [minStr := '0', minutes printString]
        ifFalse:[minStr := minutes printString].
    ^hours printString, ':', minStr, ' ', amPM.

"****  Appointment instance methods  ****"
< anAppointment
        "Answer true if the receiver's date
         and notify time are earlier than
         those of anAppointment"

    ^(date < anAppointment date)
        or:[(date = anAppointment date)
            and:[notifyTime < anAppointment notifyTime]].

<= anAppointment
        "Answer true if the receiver's date
         and notify time are the same or
         earlier than those of anAppointment"

    ^(self < anAppointment) or:[self = anAppointment].

= anAppointment
        "Answer true if the receiver's date
         and notify time are the same as
         those of anAppointment"

    ^(date = anAppointment date)
        and:[notifyTime = anAppointment notifyTime].

> anAppointment
        "Answer true if the receiver's date
         anf notify time are later than
         those of anAppointment"

    ^(self <= anAppointment) not.

>= anAppointment
        "Answer true if the receiver's date
         and notify time are the same or
         later than those of anAppointment"

    ^(self < anAppointment) not.

checkTime:timeNow date:dateToday
        "Answer true if it is time to notify
         the user of his or her appointment"

    ^(date < dateToday)
        or:[(date = dateToday)
                and:[notifyTime < timeNow]].

date
        "Answer a Date, the appointment's date"
    ^date.

date:aDate
        "Set the appointment's date to aDate"
    date := aDate.
endTime
        "Answer a Time, the appointment's end time"
    ^endTime.
endTime:aTime
        "Set the appointment's end time to aTime"
    endTime := aTime.

info
        "Answer a String with the information on
         this appointment"

    ^OrderedCollection new
        add:user, ' has an appointment';
        add:'on ', date formPrint,
            ' at ', (self timePrintString:startTime);
        add:String new;
        addAll:text;
        yourself.

notifyTime
        "Answer a Time, the time at which the
         user is to be notified"
    ^notifyTime.

notifyTime:aTime
        "Set the time at which the user is to
         be notified to aTime"
    notifyTime := aTime.

printOn:aStream
        "Add a representation of the receiver
         to aStream"
    aStream
        nextPutAll:date formPrint;
        nextPutAll:' @ ';
        nextPutAll:(self timePrintString:startTime);
        nextPutAll:' - ';
        nextPutAll:(text at:1).

startTime
        "Answer a Time, the appointment's start time"
    ^startTime.

startTime:aTime
        "Set the appointment's start time to aTime"

    startTime := aTime.

text
        "Answer an Array containing the lines of text
         that describe the appointment"
    ^text.

text:aTextArray
        "Set aTextArray as the lines of text
         that describe the appointment"
    text := aTextArray.

timePrintString:aTime
        "Answer a string with a representation of
         aTime formatted as hh:mm AM/PM"
    ^self class timePrintString:aTime.

user
        "Answer the user for whom the appointment
         was created"
    ^user.

user:userName
        "Set the user for whom the appointment
         was created to userName"
    user := userName.



[LISTING TWO]

"The AppointmentBrowser class definition"

ApplicationWindow subclass: #AppointmentBrowser
  instanceVariableNames: 
    'user appointments appointmentList
     dateEditor textEditor notifyTimeEditor
     endTimeEditor startTimeEditor '
  classVariableNames: ''
  poolDictionaries: ''

"****  AppointmentBrowser class methods  ****"

open
        "Prompt for a user name and then open
         an AppointmentBrowser for that user"
    | userName |

    Cursor offset:Display boundingBox center.
    userName := PromptDialog
                    prompt:'Enter user name'.
    userName isNil ifTrue:[^nil].
    ^self openOn:userName.

openOn:aUserName
        "Open an AppointmentBrowser for aUserName"

    ^super new
        openWithInitializeMethod:#initializeUser:
            arguments:(Array with:aUserName).

"****  AppointmentBrowser instance methods  ****"

addAppointment
        "The user as pushed the 'ADD' button so
         we need to construct a new appointment
         record and add it to the user's list"
    | appointment index |

    appointment := Appointment new
            user:user;
            date:dateEditor date;
            startTime:startTimeEditor time;
            endTime:endTimeEditor time;
            notifyTime:notifyTimeEditor time;
            text:textEditor stringList deepCopy;
            yourself.
    appointments add:appointment.
    index := appointments indexOf:appointment.
    self updateAppointmentList.
    appointmentList selectItem:index.

changeAppointment
        "The user has pushed the 'CHANGE' button so
         we need to remove the currently selected
         appointment and then add a new on with the
         current values"

    appointmentList disableDrawing.
    self removeAppointment.
    appointmentList enableDrawing.
    self addAppointment.

createWindow
        "This method was generated by the
         Widgets/V 286 Interface Editor"

  ^TitledWindow new
    yourself;
    title: 'Appointment Browser';
    closable: true;
    iconizable: true;
    size: 415 @ 322;

    addWidget: (
        appointmentList := ListBox new
            yourself;
            nameForInstVar: 'appointmentList';
            on: #select send: #selectAppointment:;
            title: 'Appointments';
            size: 390 @ 133

    ) position: 12 @ 9;
    addWidget: (
        dateEditor := DateWidget new
            yourself;
            nameForInstVar: 'dateEditor';
            title: 'DATE:';
            date: (
                Date newDay: 16
                     month:  #December
                     year:   1990
            );
            size: 114 @ 18
    ) position: 47 @ 156;
    addWidget: (
        TitledPane new
            yourself;
            title: 'WHAT FOR?';
            size: 233 @ 116;

            addWidget: (
                textEditor := TextEditWidget new
                    yourself;
                    nameForInstVar: 'textEditor';
                    verticalScrollBar: true;
                    horizontalScrollBar: false;
                    size: 219 @ 90
            ) framer: (
              FramingParameters new
                xCentered;
                yCentered
            )
    ) position: 170 @ 151;

    addWidget: (
        notifyTimeEditor := TimeWidget new
            yourself;
            nameForInstVar: 'notifyTimeEditor';
            title: 'NOTIFY AT:';
            time: (
                Time new seconds: 74673
            );
            size: 144 @ 18
    ) position: 16 @ 269;
    addWidget: (
        TitledButton new
            yourself;
            on: #release send: #changeAppointment;
            title: 'CHANGE';
            size: 77 @ 19
    ) position: 326 @ 269;
    addWidget: (
        endTimeEditor := TimeWidget new
            yourself;
            nameForInstVar: 'endTimeEditor';
            title: 'END TIME:';
            time: (
                Time new seconds: 74673
            );
            size: 136 @ 18
    ) position: 24 @ 230;
    addWidget: (
        startTimeEditor := TimeWidget new
            yourself;
            nameForInstVar: 'startTimeEditor';
            on: #valueChanged send: #startTimeChanged:;
            title: 'START TIME:';
            time: (
                Time new seconds: 74613
            );
            size: 148 @ 18
    ) position: 12 @ 192;
    addWidget: (
        TitledButton new
            yourself;
            on: #release send: #addAppointment;
            title: 'ADD';
            size: 77 @ 19
    ) position: 170 @ 269;
    addWidget: (
        TitledButton new
            yourself;
            on: #release send: #removeAppointment;
            title: 'REMOVE';
            size: 77 @ 19
    ) position: 248 @ 269.
initializeUser:argArray
        "Initialize an AppointmentBrowser for the
         user whose name is given in argArray"

    user := argArray.
    (Appointments includesKey:user)
        ifFalse:[
            Appointments
                at:user
                put:(SortedCollection
                        sortBlock:[:a :b| a < b])].
    appointments := Appointments at:user.
    self window
        on:#activated send:#updateAppointmentList;
        title:'Appointments for ', user.
    dateEditor date:Date today.
    startTimeEditor time:(Time fromSeconds:32400).  "9:00 AM"
    self
        startTimeChanged:startTimeEditor time;
        updateAppointmentList.

removeAppointment
        "The user has pushed the 'REMOVE' button so
         we need to remove the selected appointment
         from the user's list"
    | index appointment |

    appointments size = 0 ifTrue:[^self].
    index := appointmentList selectionIndex.
    appointment := appointments at:index.
    appointments remove:appointment ifAbsent:[].
    self updateAppointmentList.
    index > appointments size
        ifTrue:[index := appointments size].
    appointmentList selectItem:index.

selectAppointment:aString
        "The user has selected an appointment so
         we need to fill-in all of the appropriate
         field editors"
    | appointment |

    appointment :=
        appointments
            at:appointmentList selectionIndex.
    dateEditor date:appointment date.
    startTimeEditor time:appointment startTime.
    endTimeEditor time:appointment endTime.
    notifyTimeEditor time:appointment notifyTime.
    textEditor stringList:appointment text.

startTimeChanged:aString
        "The user has changed the start time
         so we need to supply rerasonable
         defaults for the end time and the
         notify time"
    | aTime |

    aTime := startTimeEditor time.
    "Assume appointment is one hour long"
    
    endTimeEditor
        time:(aTime addTime:(Time fromSeconds:3600)).

    "Assume notify 5-minutes before"
    notifyTimeEditor
        time:(aTime subtractTime:(Time fromSeconds:300)).

updateAppointmentList
        "Update the list of appointments"
    | size list |

    (size := appointments size) = 0 ifTrue:[^self].
    list := Array new:size.
    1 to:size do:[:index|
        list
            at:index
            put:(appointments at:index) printString].
    appointmentList  stringList:list.

user
        "Answer the name of the user for which
         this browser was opened"

    ^user.

windowLocation
        "Make the window centered on the screen"

    ^#center.



[LISTING THREE]

"The AppointmentNotifier class definition"

ApplicationWindow subclass: #AppointmentNotifier
  instanceVariableNames: 
    'active running minute text appointment '
  classVariableNames: ''
  poolDictionaries: ''

"****  AppointmentNotifier instance methods  ****"

acknowledge
        "The user has pushed th 'OK' button, so we
         need to remove the current appointment
         from the user's list"
    | user list |

    appointment isNil ifTrue:[^self].
    user := appointment user.
    (list := Appointments
                at:user
                ifAbsent:[nil]) isNil
        ifFalse:[
            list
                remove:appointment
                ifAbsent:[]].
    text
        stringList:#();
        display.
    appointment := nil.
    minute := nil.

activateFor:anAppointment
        "Display the details of anAppointment and
         bring this window to the top"

    appointment isNil
        ifTrue:[
            "Previous appointment
             has been dismissed"
            text
                disableDrawing;
                stringList:anAppointment info;
                enableDrawing.
            appointment := anAppointment].
    Terminal bell;  bell.
    Cursor offset:window origin.
    ScreenManager activateWindow:self window.

clockEvent
        "A clock tick has been received so we have
         to determine if the minute has rolled over
         and, if so, are any appointments ready"
    | now thisMinute today list appointment |

    now := Time now.
    (thisMinute := now minutes) = minute
        ifTrue:[^self].
    minute := thisMinute.
    today := Date today.
    Appointments associationsDo:[:anEntry|
        (list := anEntry value) size > 0
            ifTrue:[
                ((appointment := list first)
                        checkTime:now date:today)
                    ifTrue:[self activateFor:appointment]]].
closeWindow
        "Before closing this window, terminate the
         process that's monitoring clock events"

    active := false.
    "Wait for the process to terminate"
    [running] whileTrue:[Processor yield].
    super closeWindow.

createWindow
        "This method was generated by the
         Widgets/V 286 Interface Editor"

  ^TitledWindow new
    yourself;
    title: 'Appointment Notifier';
    closable: true;
    size: 183 @ 155;

    addWidget: (
        text := TextEditWidget new
            yourself;
            nameForInstVar: 'text';
            verticalScrollBar: true;
            horizontalScrollBar: false;
            size: 169 @ 91
    ) position: 5 @ 6;
    addWidget: (
        TitledButton new
            yourself;
            on: #release send: #acknowledge;
            title: 'OK';
            default: true;
            size: 57 @ 23
    ) framer: (
      FramingParameters new
        xCentered;
        originY: 103 relativeTo: #origin
    ).

initialize
        "Initialize a new AppointmentNotifier"
    active := false.
    running := false.
    minute := Time now minutes.
    [self run] forkAt:Processor highUserPriority.
run
        "Run the process that handles clock events"
    | timerSemaphore |

    (timerSemaphore := Smalltalk
                        at:#TimerSemaphore
                        ifAbsent:[nil])
            isNil
        ifTrue:[
            timerSemaphore := Semaphore new.
            Smalltalk
                at:#TimerSemaphore
                put:timerSemaphore].
    active := true.
    running := true.
    [active]
        whileTrue:[
            timerSemaphore wait.
            self clockEvent].
    Smalltalk removeKey:#TimerSemaphore.
    running := false.

windowLocation
        "Make the window centered on the screen"

    ^#center.




[LISTING FOUR]

"Modifications to the Process class methods"

timerInterrupt
        "Implement the timer interrupt."
    | timerSemaphore |

    PendingEvents add: (Message new
        selector: #clockEvent:;
        arguments: (Array with: 1)).
    KeyboardSemaphore signal.

    "**********************************************
    Added by Ken Ayers to support the
    Appointment Manager Application"

    timerSemaphore := Smalltalk at:#TimerSemaphore
                            ifAbsent:[nil].
    timerSemaphore notNil
        ifTrue:[timerSemaphore signal].
    "**********************************************"
    self enableInterrupts: true.




[LISTING FIVE]

"Corrections to TimeWidget methods"
"****  TimeWidget instance methods  ****"

time
    | hours |

    hours := self hours.

    (self meridianEditor value = 'PM')
        ifTrue:[
            hours < 12 ifTrue:[hours := hours + 12]]
        ifFalse:[
            hours = 12 ifTrue:[ hours := 0]].

    ^(Time fromSeconds:0)
        hours:hours;
        minutes:self minutes.

time: newTime
    | hours |

    self time = newTime ifTrue: [^self].

    hours := newTime hours.

    (hours >= 12)
        ifTrue: [
            self meridianEditor value: 'PM'.
            hours > 12 ifTrue:[hours := hours - 12]]
        ifFalse: [
            self meridianEditor value: 'AM'.
            hours = 0 ifTrue:[hours := 12]].

    self hourEditor value: hours.

    self minuteEditor value: newTime minutes.