var Spry;
if (!Spry) 
    Spry = {};
if (!Spry.Utils) 
    Spry.Utils = {};

Spry.Utils.Notifier = function(){
    this.observers = [];
    this.suppressNotifications = 0;
};

Spry.Utils.Notifier.prototype.addObserver = function(observer){
    if (!observer) 
        return;
    
    // Make sure the observer isn't already on the list.
    
    var len = this.observers.length;
    for (var i = 0; i < len; i++) {
        if (this.observers[i] == observer) 
            return;
    }
    this.observers[len] = observer;
};

Spry.Utils.Notifier.prototype.removeObserver = function(observer){
    if (!observer) 
        return;
    
    for (var i = 0; i < this.observers.length; i++) {
        if (this.observers[i] == observer) {
            this.observers.splice(i, 1);
            break;
        }
    }
};

Spry.Utils.Notifier.prototype.notifyObservers = function(methodName, data){
    if (!methodName) 
        return;
    
    if (!this.suppressNotifications) {
        var len = this.observers.length;
        for (var i = 0; i < len; i++) {
            var obs = this.observers[i];
            if (obs) {
                if (typeof obs == "function") 
                    obs(methodName, this, data);
                else 
                    if (obs[methodName]) 
                        obs[methodName](this, data);
            }
        }
    }
};

Spry.Utils.Notifier.prototype.enableNotifications = function(){
    if (--this.suppressNotifications < 0) {
        this.suppressNotifications = 0;
        Spry.Debug.reportError("Unbalanced enableNotifications() call!\n");
    }
};

Spry.Utils.Notifier.prototype.disableNotifications = function(){
    ++this.suppressNotifications;
};