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Annotation of Examples/EnterpriseObjects/DistributedEO/AppManager.m, revision 1.1

1.1     ! root        1: /*
        !             2:    AppManager.m created by enoyau on Fri 13-Jan-1995
        !             3: 
        !             4:    You may freely copy, distribute, and reuse the code in this example.
        !             5:    NeXT disclaims any warranty of any kind, expressed or implied, as to its
        !             6:    fitness for any particular use.
        !             7: */
        !             8: 
        !             9: #import "AppManager.h"
        !            10: #import "Employee.h"
        !            11: 
        !            12: // A property added to the EMPLOYEE table in the PEOPLE demo database.
        !            13: // This property is needed to avoid concurrent update to the same record.
        !            14: #define lockProperty @"lock"
        !            15: 
        !            16: @interface AppManager(private)
        !            17: - (void)_updateDisplay;
        !            18: @end
        !            19: 
        !            20: @implementation AppManager(private)
        !            21: 
        !            22: // Responsible for keeping the lock button states up-to-date and to
        !            23: // allow/disallow editing in the tableview. 
        !            24: - (void)_updateDisplay
        !            25: {
        !            26:     id currentSelection = [[eoController selectedObjects] objectAtIndex:0];
        !            27: 
        !            28:     BOOL isEditable = [currentSelection isEditable];
        !            29:     BOOL isLocked = [currentSelection isLocked];
        !            30: 
        !            31:     [lockButton setTitle:isLocked ? "Unlock" : "Lock"];
        !            32:     [lockButton setEnabled:(!isLocked) || isEditable];
        !            33: 
        !            34:     [tableView setTarget:isLocked ? nil : lockButton]; 
        !            35:     if([tableView isEditable] != isEditable) {
        !            36:         [tableView setEditable:isEditable];
        !            37:         if(!isEditable) {
        !            38:             [tableView perform:@selector(display)
        !            39:                           with:nil
        !            40:                     afterDelay:0
        !            41:                 cancelPrevious:NO];
        !            42:         }
        !            43:     }
        !            44:     return;
        !            45: }
        !            46: 
        !            47: @end
        !            48: 
        !            49: @implementation AppManager
        !            50: 
        !            51: // This notification is sent to AppManager by the DEONotificationCenter.
        !            52: - (void)databaseChange:(DEONotification *)notification
        !            53: {
        !            54:     id eoObject = [notification notificationObject];
        !            55: 
        !            56:     if( !([EOFault isFault:eoObject] || [notification isLocal]) ) {
        !            57:         EODatabaseDataSource *eoDatabasedataSource;
        !            58:         EODatabaseChannel *eoDatabaseChannel;
        !            59:         EODatabaseContext *eoDatabaseContext;
        !            60:         BOOL autoTransaction = NO;
        !            61: 
        !            62:         eoDatabasedataSource =(EODatabaseDataSource*)[eoController dataSource];
        !            63:         eoDatabaseChannel = [eoDatabasedataSource databaseChannel];
        !            64:         eoDatabaseContext = [eoDatabaseChannel databaseContext];
        !            65: 
        !            66:         // refetch the EO from the database server to preserve data integrity.
        !            67:         if (![eoDatabaseContext transactionNestingLevel]) {
        !            68:             [eoDatabaseContext beginTransaction];
        !            69:             autoTransaction = YES;
        !            70:         }
        !            71: 
        !            72:         [eoDatabaseChannel refetchObject:eoObject];
        !            73: 
        !            74:         if (autoTransaction) [eoDatabaseContext commitTransaction];
        !            75: 
        !            76:         // redisplay the data. If editing is not ended, wait until it is done
        !            77:         // (by changing the selection or the state of the lock)       
        !            78:         if([tableView isEditable]) {
        !            79:             needRedisplay = YES;
        !            80:         } else {
        !            81:             [eoController redisplay];
        !            82:             [self _updateDisplay];
        !            83:         }
        !            84:     }
        !            85:     return;
        !            86: }
        !            87: 
        !            88: // Update the lock value in the database when lock button is pressed.
        !            89: - toggleLockOnSelection:sender
        !            90: {
        !            91:     if([lockButton isEnabled]) {
        !            92:         id currentSelection;
        !            93:         NSArray *keys;
        !            94:         NSMutableDictionary *objectValue;
        !            95: 
        !            96:         currentSelection = [[eoController selectedObjects] objectAtIndex:0];
        !            97:         keys = [NSArray arrayWithObject:lockProperty];
        !            98:         objectValue = [[[currentSelection valuesForKeys:keys] mutableCopy] autorelease];
        !            99: 
        !           100:         if([[objectValue objectForKey:lockProperty] isEqual:[EONull null]]) {
        !           101:             [objectValue setObject:lockString forKey:lockProperty];
        !           102:         } else {
        !           103:             [objectValue setObject:[EONull null] forKey:lockProperty];
        !           104:         }
        !           105: 
        !           106:         [eoController setValues:objectValue forObject:currentSelection];
        !           107: 
        !           108:         [self _updateDisplay];
        !           109:     }
        !           110:     return self;
        !           111: }
        !           112: @end
        !           113: 
        !           114: @implementation AppManager(EOControllerDelegate)
        !           115: - (void)controllerDidChangeSelection:(EOController *)controller
        !           116: {
        !           117:     if(needRedisplay) {
        !           118:         [eoController redisplay];
        !           119:         needRedisplay = NO;
        !           120:     }
        !           121:     [self _updateDisplay];
        !           122: }
        !           123: @end
        !           124: 
        !           125: @implementation AppManager(EOApplicationDelegate)
        !           126: - appDidInit:sender
        !           127: {
        !           128:     EODatabaseDataSource *eoDatabaseDataSource;
        !           129:     EODatabaseChannel *eoDatabaseChannel;
        !           130:     EOAdaptorContext *eoAdaptorContext;
        !           131: 
        !           132:     eoDatabaseDataSource = [eoController dataSource];
        !           133:     eoDatabaseChannel = [eoDatabaseDataSource databaseChannel];
        !           134:     eoAdaptorContext = [[eoDatabaseChannel adaptorChannel] adaptorContext];
        !           135:     
        !           136:     // Set up as the delegate of EOController, EODatabaseChannel,
        !           137:     // and EOAdaptorContext
        !           138:     [(EOController*)eoController setDelegate:self];
        !           139:     [eoDatabaseChannel setDelegate:self]; // EO updates, inserts and deletes.
        !           140:     [eoAdaptorContext setDelegate:self];  // Transactions begin, commit or rollback.
        !           141: 
        !           142:     // Put an ImageFormatter in column 0
        !           143:     [[tableView columnAt:0] setFormatter:[[NXImageFormatter alloc] init]];
        !           144: 
        !           145:     // A double click will lock the current selection to start the
        !           146:     // editing mode
        !           147:     [tableView setTarget:lockButton];
        !           148:     [tableView setDoubleAction:@selector(performClick:)];
        !           149:     
        !           150:     // Set up the Distributed Entreprise Object notification center
        !           151:     deoNotificationCenter =
        !           152:         [[DEONotificationCenter alloc]
        !           153:                      initWithDatabaseChannel:eoDatabaseChannel
        !           154:                                       entity:[eoDatabaseDataSource entity]];
        !           155: 
        !           156:     // Register for notification whenever objects of this entity are updated
        !           157:     [deoNotificationCenter addObserver:self
        !           158:                               selector:@selector(databaseChange:)
        !           159:                       notificationName:DEOUpdate
        !           160:                                 object:nil];
        !           161: 
        !           162:     // Update instance variables
        !           163:     transactions = [NSMutableArray new];
        !           164:     needRedisplay = NO;
        !           165:     lockString = [[NSString alloc] initWithFormat:@"%s-%@-%d",
        !           166:         NXUserName(),
        !           167:         [DEONotificationCenter localHostname],
        !           168:         NXProcessID];
        !           169:     
        !           170:     [Employee setLocalLockString:lockString];
        !           171:     
        !           172:     // Force the first fetch
        !           173:     [eoController fetch:self];
        !           174: 
        !           175:     [self _updateDisplay];
        !           176:     return self;
        !           177: }
        !           178: 
        !           179: - appWillTerminate:sender
        !           180: {
        !           181:     [transactions release];
        !           182:     [lockString release];
        !           183:     [deoNotificationCenter removeObserver:self];
        !           184:     [deoNotificationCenter release];
        !           185:     return self;
        !           186: }
        !           187: @end
        !           188: 
        !           189: // We keep a list of all objects updated in the current transaction
        !           190: // and post notification of the changes when the transaction commits.
        !           191: // A more complete implementation could also keep track of insertions
        !           192: // and deletions.
        !           193: @implementation AppManager(EOAdaptorContextDelegate)
        !           194: - (void)adaptorContextDidBegin:context
        !           195: {
        !           196:     [transactions addObject:[NSMutableArray array]];
        !           197: }
        !           198: 
        !           199: - (void)adaptorContextDidCommit:context
        !           200: {
        !           201:     NSMutableDictionary *commitedTransaction = [transactions lastObject];
        !           202:     id enumerator, current;
        !           203: 
        !           204:     [transactions removeLastObject];
        !           205:     if([transactions count]) {
        !           206:         [[transactions lastObject] addObjectsFromArray:commitedTransaction];
        !           207:     } else {
        !           208:         enumerator = [commitedTransaction objectEnumerator];
        !           209:         while(current = [enumerator nextObject]) {
        !           210:             [deoNotificationCenter postNotificationName:DEOUpdate object:current];
        !           211:         }
        !           212:     }
        !           213: }
        !           214: 
        !           215: // If the transaction rolls back, there is no notification.
        !           216: - (void)adaptorContextDidRollback:context
        !           217: {
        !           218:     [transactions removeLastObject];
        !           219: }
        !           220: 
        !           221: @end
        !           222: 
        !           223: @implementation AppManager(EODatabaseChannelDelegate)
        !           224: - (void)databaseChannel:channel didUpdateObject:anEO
        !           225: {
        !           226:     [(NSMutableArray *)[transactions lastObject] addObject:anEO];
        !           227: }
        !           228: @end

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