Delegates in Objective-C - objective-c

Question

I am trying to explore some codes in Objective-C. I came across an open source program - batch renamer. I was looking at its code and adding my own implementation. There is one thing in this code that I could not understand - I was hoping someone would be able to help me out.
The problem is that there is a renamer delegate "- (void)renamed" and I have no idea how it is called. So, I was wondering how does the program know when to call/use this delegate.
The code is as follows:
#import "ControllerMain.h"
static NSString *addFilesIdentifier = #"addFiles_item";
static NSString *removeFilesIdentifier = #"removeFiles_item";
static NSString *cleanAllIdentifier = #"cleanAll_item";
static NSString *updateUrl = #"http://www.hardboiled.it/software/update.xml";
#implementation ControllerMain
- (id)init
{
self = [super init];
//init some object
tableSource = [[NSMutableArray alloc] init];
updater = [[STUpdateChecker alloc] init];
renamer = [[STRenamer alloc] init];
//set some variables
withExt = NO;//for include the extension in the renaming, default NO
renamed = NO;//is YES after renaming preview
insoverappPosition = 0;
//set the notification for NSControlTextDidChangeNotification
NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self selector:#selector(textDidEndEditing:) name:#"NSControlTextDidChangeNotification" object:nil];
return self;
}
-(void)awakeFromNib
{
//set the delegates
[tabella setDelegate:self];
[tableSource setDelegate:self];
[renamer setDelegate:self];
[updater setDelegate:self];
//check if the software is updated
[updater checkUpdateWithUrl:[NSURL URLWithString:updateUrl]];
//drag' drop - set the dragged types
[tabella registerForDraggedTypes:[NSArray arrayWithObjects: NSFilenamesPboardType, nil]];
//toolbar configuration
toolbar = [[NSToolbar alloc] initWithIdentifier:#"toolbar"];
[toolbar setDelegate:self];
//mainWindows properties
[mainWindow center];
[mainWindow setTitle:#"macXrenamer"];
[mainWindow setToolbar:toolbar];
//set the extension checkbox
[extSwitch setState:0];
//Set the custom cell imageAndTextCell
ImageAndTextCell *imageAndTextCell = nil;
NSTableColumn *tableColumn = nil;
tableColumn = [tabella tableColumnWithIdentifier:#"original_name"];
imageAndTextCell = [[[ImageAndTextCell alloc] init] autorelease];
[imageAndTextCell setEditable: NO];
[tableColumn setDataCell:imageAndTextCell];
//
//initialize the window for empty table
[self tableSourceIsEmpty];
//release the toolbar
[toolbar release];
}
- (void)dealloc
{
//release all
[tabella unregisterDraggedTypes];
[tableSource release];
[renamer release];
[super dealloc];
}
- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)sender
{
//close the application
return YES;
}
/* ################### tableSource delegates #################################*/
- (void)tableSourceIsEmpty
{
if (KDEBUG)
NSLog(#"tablesource is empty");
[upper_lower setEnabled:NO];
[from setEditable:NO];
[to setEditable:NO];
[insertText setEditable:NO];
[insertAtPosition setEditable:NO];
[insertAtPosition setIntValue:0];
[renameButton setEnabled:NO];
[annullButton setEnabled:NO];
[searchField setEditable:NO];
[replaceField setEditable:NO];
}
- (void)tableSourceIsNotEmpty
{
if (KDEBUG)
NSLog(#"tablesource is not empty");
[upper_lower setEnabled:YES];
[from setEditable:YES];
[to setEditable:YES];
[insertText setEditable:YES];
[insertAtPosition setEditable:YES];
[searchField setEditable:YES];
[replaceField setEditable:YES];
}
-(void)tableSourceDidChange
{
NSString *countString = [NSString stringWithFormat:#"%d files",[tableSource count]];
[number_of_files setStringValue:countString];
}
/*####################end tableSource delegates###############################*/
/*######################renamer delegates#####################################*/
- (void)renamed
{
NSLog(#"renaming preview ok");
NSTabViewItem *tabItem;
tabItem = [tabView selectedTabViewItem];
id tabViewId = [tabItem identifier];
if ([tabViewId isEqual:#"insert"]) {
[insertAtPosition setTextColor:[NSColor blackColor]];
}else if([tabViewId isEqual:#"remove"])
{
[from setTextColor:[NSColor blackColor]];
[to setTextColor:[NSColor blackColor]];
}
renamed = YES;
[renameButton setEnabled:YES];
[annullButton setEnabled:YES];
}
- (void)notRenamed
{
renamed = NO;
NSTabViewItem *tabItem;
tabItem = [tabView selectedTabViewItem];
id tabViewId = [tabItem identifier];
if ([tabViewId isEqual:#"insert"]) {
[insertAtPosition setTextColor:[NSColor redColor]];
}else if([tabViewId isEqual:#"remove"])
{
[from setTextColor:[NSColor redColor]];
[to setTextColor:[NSColor redColor]];
}
NSLog(#"exception in preview delegate");
[renameButton setEnabled:NO];
}
/* ###################end renamer delegates ##################################*/
//make the file extension editable
-(IBAction)makeExtEditable:(id)sender
{
if (KDEBUG)
NSLog(#"makeExtEditable action");
if ([sender state] == 0) {
withExt = NO;
}else if ([sender state] == 1) {
withExt = YES;
}
}
//add files to the table
-(IBAction)addFiles:(id)sender
{
//start the progression bar
[progBar startAnimation:self];
int result;
NSOpenPanel *oPanel = [NSOpenPanel openPanel];
[oPanel setCanChooseFiles:YES];
[oPanel setAllowsMultipleSelection:YES];
[oPanel setResolvesAliases:NO];
result = [oPanel runModalForTypes:nil];
if (result == NSOKButton) {
NSArray *filesToOpen = [oPanel filenames];
[tableSource add:filesToOpen];
[tabella reloadData];
}
//stop the progression bar
[progBar stopAnimation:self];
}
//remove files from the table
-(IBAction)removeFiles:(id)sender
{
if(KDEBUG)
NSLog(#"remove the selected file from the table");
[progBar startAnimation:self];
NSIndexSet *selected = [tabella selectedRowIndexes];
[tableSource removeAtIndexes:selected];
[tabella reloadData];
[progBar stopAnimation:self];
}
//remove all files from the table
-(IBAction)clearTable:(id)sender
{
if(KDEBUG)
NSLog(#"clear all table");
[progBar startAnimation:self];
[tableSource cleanAll];
[tabella reloadData];
[progBar stopAnimation:self];
}
//annull
-(IBAction)annulRenaming:(id)sender
{
[tableSource annull];
NSTabViewItem *tabItem;
tabItem = [tabView selectedTabViewItem];
id tabViewId = [tabItem identifier];
if ([tabViewId isEqual:#"insert"]) {
[insertAtPosition setTextColor:[NSColor blackColor]];
}else if([tabViewId isEqual:#"remove"])
{
[from setTextColor:[NSColor blackColor]];
[to setTextColor:[NSColor blackColor]];
}
renamed = NO;
[renameButton setEnabled:NO];
[tabella reloadData];
}
/*###########################log section######################################*/
-(IBAction)showLogWindows:(id)sender{
if ([logWindow isVisible]) {
[logWindow setIsVisible:FALSE];
}else {
[logWindow setIsVisible:TRUE];
}
}
-(void)addToLog:(NSString *)text
{
NSString *textLog = [text stringByAppendingString:#"\n\r"];
NSRange endRange;
endRange.location = [[logField textStorage] length];
endRange.length = 0;
[logField replaceCharactersInRange:endRange withString:textLog];
endRange.length = [textLog length];
[logField scrollRangeToVisible:endRange];
}
/*#######################end log section######################################*/
/*######################editing actions#######################################*/
-(IBAction)finalRenaming:(id)sender
{
if(KDEBUG)
NSLog(#"renaming button pressed");
//start the progression bar
[progBar startAnimation:self];
//count of the files really renamed
int countRenamed = 0;
//count of the renaming error
int errRenamed = 0;
//the result of rename()
int renameResult;
//the enumerator and the obj
NSEnumerator *en = [tableSource objectEnumerator];
id row;
if(renamed)
{
while(row = [en nextObject])
{
renameResult = rename([[row objectAtIndex:0] fileSystemRepresentation], [[row objectAtIndex:1] fileSystemRepresentation]);
if(renameResult == 0){
NSString *textLog = [NSString stringWithFormat:#"%# renamed with\n %#", [row objectAtIndex:0],[row objectAtIndex:1]];
NSLog(textLog);
[self addToLog:textLog];
countRenamed++;
}else {
NSString *textLog =[NSString stringWithFormat: #"Error in file renaming %#", [row objectAtIndex:0]];
NSLog(textLog);
[self addToLog:textLog];
errRenamed++;
}
}
if(errRenamed >0){
//open the panel alert
int result;
result = NSRunAlertPanel(#"Renaming error. Please check the log", #"Error!", #"Ok", NULL, NULL);
}
//print the result of renaming
[notiField setStringValue:[NSString stringWithFormat:#"renamed %d/%d files, %d errors", countRenamed,[tableSource count],errRenamed]];
//
[tableSource reinitialize];
[tabella reloadData];
[renameButton setEnabled:NO];
[annullButton setEnabled:NO];
[progBar stopAnimation:self];
}
}
- (void)textDidEndEditing:(NSNotification *)aNotification
{
[progBar startAnimation:self];
NSTabViewItem *tabItem;
tabItem = [tabView selectedTabViewItem];
id tabViewId = [tabItem identifier];
if ([tabViewId isEqual:#"insert"]) {
if(KDEBUG)
NSLog(#"insert selected");
if(insoverappPosition == 1)
{
if(KDEBUG)
NSLog(#"overwrite selected");
tableSource = [renamer overwriteChar:tableSource insertText:[insertText stringValue] position:[insertAtPosition intValue] withExt:withExt];
}else if(insoverappPosition == 0){
if(KDEBUG)
NSLog(#"insert selected");
tableSource = [renamer insertChar:tableSource insertText:[insertText stringValue] position:[insertAtPosition intValue] withExt:withExt];
}else if(insoverappPosition == 2){
if(KDEBUG)
NSLog(#"append selected");
tableSource = [renamer appendChar:tableSource appendText:[insertText stringValue] withExt:withExt];
}
}else if ([tabViewId isEqual:#"remove"]) {
if(KDEBUG)
NSLog(#"remove selected");
tableSource = [renamer removeChar:tableSource from:[from intValue] to:[to intValue] withExt:withExt];
}else if([tabViewId isEqual:#"search"]){
if(KDEBUG)
NSLog(#"search selected");
tableSource = [renamer searchAndReplace:tableSource string:[searchField stringValue] withString:[replaceField stringValue] withExt:withExt];
}
[progBar stopAnimation:self];
}
-(IBAction)upLowerCellClicked:(id)sender
{
NSCell* cell;
cell = [upper_lower selectedCell];
int tag = [cell tag];
if (tag == 0) {
if(KDEBUG)
NSLog(#"lowercase selected");
tableSource = [renamer makeLowerCase:tableSource withExt:withExt];
[renameButton setEnabled:YES];
[annullButton setEnabled:YES];
[tabella reloadData];
}
else if(tag == 1){
if(KDEBUG)
NSLog(#"uppercase selected");
tableSource = [renamer makeUpperCase:tableSource withExt:withExt];
[renameButton setEnabled:YES];
[annullButton setEnabled:YES];
[tabella reloadData];
}
}
-(IBAction)insertOverwriteClicked:(id)sender
{
if(KDEBUG)
NSLog(#"insertOverwriteClicked");
NSCell* cell;
cell = [insert_overwrite selectedCell];
int tag = [cell tag];
if(tag == 0)
{
if(KDEBUG)
NSLog(#"insert");
[insertAtPosition setEnabled:YES];
insoverappPosition = 0;
}else if(tag==1){
if(KDEBUG)
NSLog(#"overwrite");
[insertAtPosition setEnabled:YES];
insoverappPosition = 1;
}else if (tag==2) {
if(KDEBUG)
NSLog(#"append");
[insertAtPosition setEnabled:NO];
insoverappPosition = 2;
}
}
/*################end editing actions#########################################*/
-(void)newUpdateIsOnline
{
NSLog(#"newUpdateIsOnline");
BOOL retval;
retval = (NSAlertDefaultReturn == NSRunAlertPanel(#"Update Available", #"Update now or later", #"Update", #"Cancel", nil, nil));
if(retval){
if(KDEBUG)
NSLog(#"update now");
[[NSWorkspace sharedWorkspace] openURL:[NSURL URLWithString:#"http://www.hardboiled.it/software/rinominatore-upgrade.zip"]];
//to edit
//[[NSNotificationCenter defaultCenter] postNotificationName:#"openSheetNotification" object:self userInfo:nil];
}else {
if(KDEBUG)
NSLog(#"cancel the update");
}
//release the updater. now is useless
[updater release];
}
/*################nstableview delegates#######################################*/
- (int)numberOfRowsInTableView:(NSTableView *)aTableView
{
return [tableSource count];
}
- (id)tableView:(NSTableView *)aTableView objectValueForTableColumn:(NSTableColumn *)aTableColumn row:(int)rowIndex
{
if ([[aTableColumn identifier] isEqualToString: #"original_name"]) {
id obj = [tableSource objectAtRow:rowIndex atIndex:0] ;
return [obj lastPathComponent];
//return theIcon;
}else if([[aTableColumn identifier] isEqualToString: #"new_name"]){
id obj = [tableSource objectAtRow:rowIndex atIndex:1] ;
return [obj lastPathComponent];
}
return nil;
}
- (void)tableView:(NSTableView *)aTableView willDisplayCell:(id)cell forTableColumn:(NSTableColumn *)aTableColumn row:(int)rowIndex
{
if(cell_with_icon)
{
if ( [[aTableColumn identifier] isEqualToString:#"original_name"] ){
[((ImageAndTextCell*) cell) setImage:[tableSource objectAtRow:rowIndex atIndex:2]];
}
}
}
/* ###############end nstableview delegates #################################*/
/*############### nstoolbar delegates #######################################*/
- (NSArray *) toolbarAllowedItemIdentifiers: (NSToolbar *) toolbar
{
return [NSArray arrayWithObjects:addFilesIdentifier,
removeFilesIdentifier,cleanAllIdentifier,
NSToolbarFlexibleSpaceItemIdentifier,
NSToolbarSpaceItemIdentifier,
NSToolbarSeparatorItemIdentifier, nil];;
}
- (NSArray *) toolbarDefaultItemIdentifiers: (NSToolbar *)toolbar
{
return [NSArray arrayWithObjects:addFilesIdentifier,
removeFilesIdentifier,NSToolbarFlexibleSpaceItemIdentifier,cleanAllIdentifier, nil];
}
- (NSToolbarItem *)toolbar:(NSToolbar *)toolbar itemForItemIdentifier:(NSString *)itemIdentifier willBeInsertedIntoToolbar:(BOOL)flag
{
NSToolbarItem *toolbarItem = nil;
if ([itemIdentifier isEqualTo:addFilesIdentifier]) {//button addfiles
toolbarItem = [[NSToolbarItem alloc] initWithItemIdentifier:itemIdentifier];
[toolbarItem setLabel:#"Add"];
[toolbarItem setPaletteLabel:[toolbarItem label]];
[toolbarItem setToolTip:#"Add"];
[toolbarItem setImage:[NSImage imageNamed:#"add.icns"]];
[toolbarItem setTarget:self];
[toolbarItem setAction:#selector(addFiles:)];
}else if ([itemIdentifier isEqualTo:removeFilesIdentifier]) {//button remove files
toolbarItem = [[NSToolbarItem alloc] initWithItemIdentifier:itemIdentifier];
[toolbarItem setLabel:#"Remove"];
[toolbarItem setPaletteLabel:[toolbarItem label]];
[toolbarItem setToolTip:#"Remove"];
[toolbarItem setImage:[NSImage imageNamed:#"remove.icns"]];
[toolbarItem setTarget:self];
[toolbarItem setAction:#selector(removeFiles:)];
}else if ([itemIdentifier isEqualTo:cleanAllIdentifier]) {//button clean
toolbarItem = [[NSToolbarItem alloc] initWithItemIdentifier:itemIdentifier];
[toolbarItem setLabel:#"Clean All"];
[toolbarItem setPaletteLabel:[toolbarItem label]];
[toolbarItem setToolTip:#"Clean the table"];
[toolbarItem setImage:[NSImage imageNamed:#"cleanAll.icns"]];
[toolbarItem setTarget:self];
[toolbarItem setAction:#selector(clearTable:)];
}
return [toolbarItem autorelease];
}
/*###############end nstoolbar delegates #####################################*/
/*################drag'n drop delegates #####################################*/
- (BOOL)tableView:(NSTableView *)tv writeRowsWithIndexes:(NSIndexSet *)rowIndexes toPasteboard:(NSPasteboard*)pboard {
// Drag and drop support
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:rowIndexes];
[pboard declareTypes:[NSArray arrayWithObject:NSFilenamesPboardType] owner:self];
[pboard setData:data forType:NSFilenamesPboardType];
return YES;
}
- (NSDragOperation)tableView:(NSTableView*)tv validateDrop:(id <NSDraggingInfo>)info proposedRow:(int)row proposedDropOperation:(NSTableViewDropOperation)op
{
// Add code here to validate the drop
if (KDEBUG)
NSLog(#"validate Drop");
return NSDragOperationEvery;
}
- (BOOL)tableView:(NSTableView*)tv acceptDrop:(id )info row:(int)row dropOperation:(NSTableViewDropOperation)op
{
if (KDEBUG)
NSLog(#"acceptDrop");
NSPasteboard *pboard = [info draggingPasteboard];
if ( [[pboard types] containsObject:NSFilenamesPboardType] ) {
NSArray *files = [pboard propertyListForType:NSFilenamesPboardType];
[tableSource add:files];
}
[tabella reloadData];
return YES;
}
/*################end drag'n drop delegates ##################################*/
#end

Answer 1

The delegate is the object, not the method. The ControllerMain object is set as some other object's delegate. When that other object sees the condition that tells it renaming has occurred (whatever that means), it executes something along the lines of [[self delegate] renamed], which calls the ControllerMain method.