observable.js

当前比较流行的,漂亮的JS框架,这里面用到的API文档

            var returnValue, v, cancel;
            var obj = this;

            var makeCall = function(fn, scope, args){
                if((v = fn.apply(scope || obj, args)) !== undefined){
                    if(typeof v === 'object'){
                        if(v.returnValue !== undefined){
                            returnValue = v.returnValue;
                        }else{
                            returnValue = v;
                        }
                        if(v.cancel === true){
                            cancel = true;
                        }
                    }else if(v === false){
                        cancel = true;
                    }else {
                        returnValue = v;
                    }
                }
            }

            this[method] = function(){
                returnValue = v = undefined; cancel = false;
                var args = Array.prototype.slice.call(arguments, 0);
                for(var i = 0, len = e.before.length; i < len; i++){
                    makeCall(e.before[i].fn, e.before[i].scope, args);
                    if(cancel){
                        return returnValue;
                    }
                }

                if((v = e.originalFn.apply(obj, args)) !== undefined){
                    returnValue = v;
                }

                for(var i = 0, len = e.after.length; i < len; i++){
                    makeCall(e.after[i].fn, e.after[i].scope, args);
                    if(cancel){
                        return returnValue;
                    }
                }
                return returnValue;
            };
        }
        return e;
    },

    // adds an "interceptor" called before the original method
    beforeMethod : function(method, fn, scope){
        var e = this.getMethodEvent(method);
        e.before.push({fn: fn, scope: scope});
    },

    // adds a "sequence" called after the original method
    afterMethod : function(method, fn, scope){
        var e = this.getMethodEvent(method);
        e.after.push({fn: fn, scope: scope});
    },

    removeMethodListener : function(method, fn, scope){
        var e = this.getMethodEvent(method);
        for(var i = 0, len = e.before.length; i < len; i++){
            if(e.before[i].fn == fn && e.before[i].scope == scope){
                e.before.splice(i, 1);
                return;
            }
        }
        for(var i = 0, len = e.after.length; i < len; i++){
            if(e.after[i].fn == fn && e.after[i].scope == scope){
                e.after.splice(i, 1);
                return;
            }
        }
    }
};
/**
 * Appends an event handler to this element (shorthand for addListener)
 * @param {String}   eventName     The type of event to listen for
 * @param {Function} handler        The method the event invokes
 * @param {Object}   scope (optional) The scope in which to execute the handler
 * function. The handler function's "this" context.
 * @param {Object}   options  (optional)
 * @method
 */
Ext.util.Observable.prototype.on = Ext.util.Observable.prototype.addListener;
/**
 * Removes a listener (shorthand for removeListener)
 * @param {String}   eventName     The type of event to listen for
 * @param {Function} handler        The handler to remove
 * @param {Object}   scope  (optional) The scope (this object) for the handler
 * @method
 */
Ext.util.Observable.prototype.un = Ext.util.Observable.prototype.removeListener;

/**
 * Starts capture on the specified Observable. All events will be passed
 * to the supplied function with the event name + standard signature of the event
 * <b>before</b> the event is fired. If the supplied function returns false,
 * the event will not fire.
 * @param {Observable} o The Observable to capture
 * @param {Function} fn The function to call
 * @param {Object} scope (optional) The scope (this object) for the fn
 * @static
 */
Ext.util.Observable.capture = function(o, fn, scope){
    o.fireEvent = o.fireEvent.createInterceptor(fn, scope);
};

/**
 * Removes <b>all</b> added captures from the Observable.
 * @param {Observable} o The Observable to release
 * @static
 */
Ext.util.Observable.releaseCapture = function(o){
    o.fireEvent = Ext.util.Observable.prototype.fireEvent;
};

(function(){

    var createBuffered = function(h, o, scope){
        var task = new Ext.util.DelayedTask();
        return function(){
            task.delay(o.buffer, h, scope, Array.prototype.slice.call(arguments, 0));
        };
    };

    var createSingle = function(h, e, fn, scope){
        return function(){
            e.removeListener(fn, scope);
            return h.apply(scope, arguments);
        };
    };

    var createDelayed = function(h, o, scope){
        return function(){
            var args = Array.prototype.slice.call(arguments, 0);
            setTimeout(function(){
                h.apply(scope, args);
            }, o.delay || 10);
        };
    };

    Ext.util.Event = function(obj, name){
        this.name = name;
        this.obj = obj;
        this.listeners = [];
    };

    Ext.util.Event.prototype = {
        addListener : function(fn, scope, options){
            scope = scope || this.obj;
            if(!this.isListening(fn, scope)){
                var l = this.createListener(fn, scope, options);
                if(!this.firing){
                    this.listeners.push(l);
                }else{ // if we are currently firing this event, don't disturb the listener loop
                    this.listeners = this.listeners.slice(0);
                    this.listeners.push(l);
                }
            }
        },

        createListener : function(fn, scope, o){
            o = o || {};
            scope = scope || this.obj;
            var l = {fn: fn, scope: scope, options: o};
            var h = fn;
            if(o.delay){
                h = createDelayed(h, o, scope);
            }
            if(o.single){
                h = createSingle(h, this, fn, scope);
            }
            if(o.buffer){
                h = createBuffered(h, o, scope);
            }
            l.fireFn = h;
            return l;
        },

        findListener : function(fn, scope){
            scope = scope || this.obj;
            var ls = this.listeners;
            for(var i = 0, len = ls.length; i < len; i++){
                var l = ls[i];
                if(l.fn == fn && l.scope == scope){
                    return i;
                }
            }
            return -1;
        },

        isListening : function(fn, scope){
            return this.findListener(fn, scope) != -1;
        },

        removeListener : function(fn, scope){
            var index;
            if((index = this.findListener(fn, scope)) != -1){
                if(!this.firing){
                    this.listeners.splice(index, 1);
                }else{
                    this.listeners = this.listeners.slice(0);
                    this.listeners.splice(index, 1);
                }
                return true;
            }
            return false;
        },

        clearListeners : function(){
            this.listeners = [];
        },

        fire : function(){
            var ls = this.listeners, scope, len = ls.length;
            if(len > 0){
                this.firing = true;
                var args = Array.prototype.slice.call(arguments, 0);
                for(var i = 0; i < len; i++){
                    var l = ls[i];
                    if(l.fireFn.apply(l.scope||this.obj||window, arguments) === false){
                        this.firing = false;
                        return false;
                    }
                }
                this.firing = false;
            }
            return true;
        }
    };
})();