gistfile1.mm

@interface MyApplication : NSApplication {
    NSTimer *idleTimer;
    NSMutableArray *idleTimerObjects;
    unsigned int elapsedSeconds;
}

- (void)sendEvent:(NSEvent *)anEvent;
- (void)timerInvocation;
- (BOOL)isUser5SecondsIdle;
- (void)finishIdle;
- (void)addIdleTimer:(IdleTimer *)timerObject;
- (void)removeIdleTimer:(IdleTimer *)timerObject;

@end

#import "MyApplication.h"
#import "IdleTimer.h"

@implementation MyApplication

- (id) init
{
    self = [super init];
    if (self != nil) {
        elapsedSeconds = 0;
        idleTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timerInvocation) userInfo:nil repeats:YES];
        idleTimerObjects = [[NSMutableArray array] retain];
    }
    return self;
}

- (void) dealloc
{
    [idleTimer release];
    [idleTimerObjects release];
    [super dealloc];
}

- (void)sendEvent:(NSEvent *)anEvent;
{
    [super sendEvent:anEvent];
    // you can filter events here
    if (elapsedSeconds >= 1) 
        [self finishIdle];
    
    elapsedSeconds = 0;
}

- (void)timerInvocation;
{
    elapsedSeconds++;
    
    for (NSValue *temp in idleTimerObjects) {
        if (elapsedSeconds == [[temp nonretainedObjectValue] interval]) {
            [[temp nonretainedObjectValue] timerBeginsIdling:self];
        }
    }
}

- (void)finishIdle;
{
    for (NSValue *temp in idleTimerObjects) {
        if ([[temp nonretainedObjectValue] isIdle]) {
            [[temp nonretainedObjectValue] timerFinishedIdling:self];
        }
    }
}

- (void)addIdleTimer:(IdleTimer *)timerObject;
{   
    NSValue *value = [NSValue valueWithNonretainedObject:timerObject];
    [idleTimerObjects addObject:value];
}

- (void)removeIdleTimer:(IdleTimer *)timerObject;
{
    for (NSValue *temp in idleTimerObjects) {
        if ([[NSValue valueWithNonretainedObject:timerObject] isEqual:temp]) {
            [idleTimerObjects removeObject:temp];
            break;
        }
    }
}

- (BOOL)isUser5SecondsIdle;
{
    return (elapsedSeconds >= 5);
}

@end