#!/usr/bin/perl -w
# Copyright (C) 2004 by Steve Litt
# Licensed with the GNU General Public License, Version 2
# ABSOLUTELY NO WARRANTY, USE AT YOUR OWN RISK
# See http://www.gnu.org/licenses/gpl.txt
use strict; # prevent hard to find errors
use Node; # Use Node.pm tool
package Callbacks;
sub new()
{
my($type) = $_[0];
my($self) = {};
bless($self, $type);
return($self);
}
#=================================================================
# This callback places asterisks in the value of years, months and
# days whose anscestors have appointments, one asterisk per appointment
#=================================================================
sub cbMakeMarks()
{
my($self, $checker, $level) = @_;
return unless defined($checker); # don't process undef node
#### PROCESS ONLY DAY, MONTH OR YEAR NODES
return unless (
$checker->getType() eq "Day" ||
$checker->getType() eq "Month" ||
$checker->getType() eq "Year"
);
#### COUNT APPOINTMENTS IN DESCENDENTS
my $count = 0;
my $childNode = $checker->getFirstChild();
while(defined($childNode))
{
if($checker->getType() eq "Day")
{
if(defined($childNode->getValue()))
{
$count++;
}
}
else
{
if($childNode->hasAttribute("appointments"))
{
$count += $childNode->getAttribute("appointments");
}
}
$childNode = $childNode->getNextSibling();
}
#### PLACE COUNT IN ATTRIBUTE
$checker->setAttribute("appointments", $count);
#### MARK STARS, ONE FOR EACH APPOINTMENT IN DESCENDENTS
if($count > 0)
{
my $string;
for(my $n=0; $n < $count; $n++){$string .= '*';}
$checker->setValue($string);
}
}
#=================================================================
# This callback operates ONLY on day nodes. When
# called from a day node, it inserts hourlong appointment slots
# starting at 8am and ending at 5pm. The code is pretty
# straightforward.
#=================================================================
sub cbInsertHours()
{
my($self, $checker, $level) = @_;
unless (defined($checker)) {return -999;} # don't process undef node
return unless $checker->getType() eq "Day"; # Insert hours under days only
my $checker2;
for(my $n=8; $n <= 16; $n++)
{
my $startHour = "$n:00";
my $n2 = $n + 1;
my $endHour = "$n2:00";
my $node = Node->new("$startHour" . "-" . "$endHour", "Hour", undef);
if($checker->hasFirstChild())
{
$checker2 = $checker2->insertSiblingAfterYou($node);
}
else
{
$checker2 = $checker->insertFirstChild($node);
}
}
}
#=================================================================
# The cbPrintNode() callback prints the name of the node,
# and its value if a value is defined. It's very straighforward.
#=================================================================
sub cbPrintNode()
{
my($self, $checker, $level) = @_;
unless (defined($checker)) {return -999;} # don't process undef node
#### DON'T PRINT LEVEL 0 (CALENDER)
return if $level == 0;
for(my $n=1; $n < $level; $n++) { print "\t";}
print $checker->getName() if $checker->hasName();
print ": ";
print $checker->getValue() if $checker->hasValue();
print "\n";
}
package Main;
###########################################################################
# The makeAppointments() subroutine manually makes several appointments
# To facilitate a later demonstration of node swapping, the June 22
# and Sept 22 appoinments are accidentally switched
###########################################################################
sub makeAppointments($)
{
my $yearNode = shift;
#### MARCH 22 AT 8AM
my $monthNode = $yearNode->getFirstChild() -> #January
getNextSibling() -> #February
getNextSibling(); #March
my $dayNode = $monthNode->getFirstChild();
while($dayNode->getName() != 22)
{
$dayNode = $dayNode->getNextSibling();
unless(defined($dayNode))
{
die "No March 22\n";
}
}
my $hourNode = $dayNode->getFirstChild();
$hourNode->setValue("Spring Cleaning");
#### JUNE 22 AT 9AM
#### WRONGLY LABELED AS FALL FESTIVAL
#### INSTEAD OF SUMMER BREAK
$monthNode = $monthNode->getNextSibling() -> # April
getNextSibling() -> # May
getNextSibling(); # June
$dayNode = $monthNode->getFirstChild();
while($dayNode->getName() != 22)
{
$dayNode = $dayNode->getNextSibling();
unless(defined($dayNode))
{
die "No June 22\n";
}
}
$hourNode = $dayNode->getFirstChild()->getNextSibling();
$hourNode->setValue("Fall Festival");
#### SEPTEMBER 22 AT 10AM
#### WRONGLY LABELED AS FALL FESTIVAL
#### INSTEAD OF SUMMER BREAK
$monthNode = $monthNode->getNextSibling() -> # July
getNextSibling() -> # August
getNextSibling(); # September
$dayNode = $monthNode->getFirstChild();
while($dayNode->getName() != 22)
{
$dayNode = $dayNode->getNextSibling();
unless(defined($dayNode))
{
die "No September 22\n";
}
}
$hourNode = $dayNode -> getFirstChild() -> #8-9
getNextSibling() -> # 9-10
getNextSibling(); # 10-11
$hourNode->setValue("Summer Break");
#### DECEMBER 22 FROM 3PM TO 5PM (2 TIMESLOTS)
#### HAPPY HOLIDAYS PARTY
$monthNode = $monthNode->getNextSibling() -> # October
getNextSibling() -> # November
getNextSibling(); # December
$dayNode = $monthNode->getFirstChild();
while($dayNode->getName() != 22)
{
$dayNode = $dayNode->getNextSibling();
unless(defined($dayNode))
{
die "No December 22\n";
}
}
$hourNode = $dayNode->getFirstChild();
while($hourNode->getName() ne "15:00-16:00")
{
$hourNode = $hourNode->getNextSibling();
unless(defined($hourNode))
{
die "No 4pm slot\n";
}
}
$hourNode->setValue("Happy Holidays Party");
$hourNode = $hourNode->getNextSibling();
$hourNode->setValue("Happy Holidays Party");
#### DECEMBER 30 AT 9AM BUY PARTY SUPPLIES
while($dayNode->getName() != 30)
{
$dayNode = $dayNode->getNextSibling();
unless(defined($dayNode))
{
die "No December 30\n";
}
}
$hourNode = $dayNode->getFirstChild()->getNextSibling();
$hourNode->setValue("Buy Party Supplies");
}
###########################################################################
# The insertMonthsAndDays() iterates through @monthNames. For each, it
# creates a month node, and then under than node iterates days from 1 to
# that month's entry in the @monthLengths array.
#
# Note that we could have avoided using a nested loop by using a Walker
# and associated callback to install the days under every month. In such
# a case the array of month lengths would have been placed in the Callback
# object. However, for the sake of variety, we chose to use a nested loop
# to load the months and days.
###########################################################################
sub insertMonthsAndDays($)
{
my $yearNode = shift;
my $checker = $yearNode;
my $checker2;
my @monthNames=("January", "February", "March", "April", "May",
"June", "July", "August", "September", "October",
"November", "December");
my @monthLengths=(31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
my $monthSS = 0;
foreach my $monthName (@monthNames)
{
my $node = Node->new($monthName, "Month", undef);
$node->setAttribute("days", $monthLengths[$monthSS]);
if($yearNode->hasFirstChild())
{
$checker = $checker->insertSiblingAfterYou($node);
}
else
{
$checker = $yearNode->insertFirstChild($node);
}
for(my $n=1; $n <= $monthLengths[$monthSS]; $n++)
{
$node = Node->new($n, "Day", undef);
if($checker->hasFirstChild())
{
$checker2 = $checker2->insertSiblingAfterYou($node);
}
else
{
$checker2 = $checker->insertFirstChild($node);
}
}
$monthSS++;
}
}
###########################################################################
# This subroutine switches the June 22 9am appointment and the
# September 22 10am appointment. In each case, both the appointment
# text and the time needed switching.
#
# The sane way to accomplish this task would have been to modify
# the nodes in place. However, this subroutine was created solely to
# demonstrate the movement of nodes, so that's what we did.
#
# Note that the fact that the two are at different times complicates the
# situation. It's not enough to just trade nodes -- the Sept 9am node
# must be placed after the existing June 10am node, which itself is after
# the erroneous June 9am node containing what should be September's
# appointment. After such placement, the original June 9am node must
# have its name updated so that it is a 10am node. A similar process
# takes place for September. The original nodes are also deleted.
#
# Please follow the (convoluted and contrived) logic:
# 1. Store the June hour node in $juneNode
# 2. Store the September hour node in $septNode
# 3. After the existing June 10am, place a CLONE of the Sept appointment
# 4. Before the existing Sept 9am, place a CLONE of the June appointment
# 5. Delete the original June appointment
# 6. Delete the original September appointment
# 7. On the original June 10am node, make it 9am
# 8. On the original September 9am node, make it 10am
###########################################################################
sub switchJuneAndSeptemberAppointments($)
{
my $yearNode = shift;
#### FIND NODE FOR JUNE 22 9AM APPOINTMENT
my $juneNode = $yearNode->getFirstChild();
while(defined($juneNode))
{
last if $juneNode->getName() eq "June";
$juneNode = $juneNode->getNextSibling();
}
die "Cannot find month of June\n" unless defined($juneNode);
$juneNode = $juneNode->getFirstChild();
while(defined($juneNode))
{
last if $juneNode->getName() eq "22";
$juneNode = $juneNode->getNextSibling();
}
die "Cannot find June 22\n" unless defined($juneNode);
$juneNode = $juneNode->getFirstChild();
while(defined($juneNode))
{
last if $juneNode->getName() eq "9:00-10:00";
$juneNode = $juneNode->getNextSibling();
}
die "Cannot find June 22 at 9am\n" unless defined($juneNode);
#### FIND NODE FOR SEPTEMBER 22 10AM APPOINTMENT
my $septNode = $yearNode->getFirstChild();
while(defined($septNode))
{
last if $septNode->getName() eq "September";
$septNode = $septNode->getNextSibling();
}
die "Cannot find month of September\n" unless defined($septNode);
$septNode = $septNode->getFirstChild();
while(defined($septNode))
{
last if $septNode->getName() eq "22";
$septNode = $septNode->getNextSibling();
}
die "Cannot find September 22\n" unless defined($septNode);
$septNode = $septNode->getFirstChild();
while(defined($septNode))
{
last if $septNode->getName() eq "10:00-11:00";
$septNode = $septNode->getNextSibling();
}
die "Cannot find September 22 at 9am\n" unless defined($septNode);
#### SWITCH THE NODES
my $newJune = $juneNode->getNextSibling()->insertSiblingAfterYou($septNode->clone());
my $newSept = $septNode->getPrevSibling()->insertSiblingBeforeYou($juneNode->clone());
$juneNode->deleteSelf();
$septNode->deleteSelf();
#### FIX NAMES OF SURROUNDING CLONES
$newJune->getPrevSibling()->setName("9:00-10:00");
$newSept->getNextSibling()->setName("10:00-11:00");
return;
}
###########################################################################
# In the main routine, you carry out or delegate the following tasks
# in order to create an appointment calendar:
# 1. Insert single level 0 and 1 nodes
# 2. Instantiate the Callbacks object
# 3. Insert all month and day nodes
# 4. Insert all hour nodes
# 5. Make appointments
# erroneously switching the june 22 & Sept 22 appointments
# 6. Mark days, months and years containing appointments
# 7. Output the calendar
# 8. Switch back June22 and Sept22
# 9. Re mark days, months and years
# 10. Output a separator between bad and good calendars
# 11. Re output the calendar
#
###########################################################################
sub main()
{
#### INSERT SINGLE LEVEL 0 AND 1 NODES
my $topNode=Node->new("Calender", "Calender", "Calender");
my $yearNode=$topNode->insertFirstChild(Node->new("2004", "Year", undef));
#### INSTANTIATE THE Callbacks OBJECT
my $callbacks = Callbacks->new();
#### INSERT MONTH AND DAY NODES
insertMonthsAndDays($yearNode);
#### INSERT THE HOURS USING A Walker
my $walker = Walker->new
(
$topNode,
[\&Callbacks::cbInsertHours, $callbacks]
);
$walker->walk();
#### MAKE A FEW APPOINTMENTS
#### ACCIDENTALLY SWITCHING SUMMER AND FALL
makeAppointments($yearNode);
#### MARK DAYS, MONTHS AND YEAR THAT HAVE APPOINTMENTS
#### USING A WALKER WITH ONLY A RETURN CALLBACK
$walker = Walker->new
(
$topNode,
undef,
[\&Callbacks::cbMakeMarks, $callbacks]
);
$walker->walk();
#### WALK THE NODE TREE,
#### OUTPUTTING THE CALENDER
$walker = Walker->new
(
$topNode,
[\&Callbacks::cbPrintNode, $callbacks]
);
$walker->walk();
#### CORRECT THE MISTAKE
#### SWITCH JUNE 22 AND SEPT 22
switchJuneAndSeptemberAppointments($yearNode);
#### RE-MARK DAYS, MONTHS AND YEAR THAT HAVE APPOINTMENTS
#### USING A WALKER WITH ONLY A RETURN CALLBACK
$walker = Walker->new
(
$topNode,
undef,
[\&Callbacks::cbMakeMarks, $callbacks]
);
$walker->walk();
#### OUTPUT A SEPARATOR BETWEEN ORIGINAL AND CORRECTED CALENDARS
for (my $n=0; $n<5; $n++)
{
print "######################################################\n";
}
#### RE-WALK THE NODE TREE,
#### RE-OUTPUTTING THE CALENDER
$walker = Walker->new
(
$topNode, # start with this node
[\&Callbacks::cbPrintNode, $callbacks] # do this on entry to each node
);
$walker->walk();
}
main();
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