发布消息很简单，首先我们需要在我们的控制器里为 requestNotificationChannel 引入一些依赖. 你可以在下面dataService的定义第二行看到这个. 当事件发生时，如果需要向需要了解有变化发生的其它对象发送信号, 你只需要调用requestNotificationChannel上恰当的通知方法就可以了. 如果你注意到了dataService的 saveHop, deleteHop 和 addHop 方法, 你就会看到它们都调用了 requestNotificationChannel 上的dataUpdated方法， 这个方法将会给侦听器发送信号，侦听器则已经用 onDataUpdated 方法注册过了.
// define the data service that manages the data
.factory('dataService', ['requestNotificationChannel', function (requestNotificationChannel) {
// private data
var hops = [
{ "_id": { "$oid": "50ae677361d118e3646d7d6c"}, "Name": "Admiral", "Origin": "United Kingdom", "Alpha": 14.75, "Amount": 0.0, "Use": "Boil", "Time": 0.0, "Notes": "Bittering hops derived from Wye Challenger. Good high-alpha bittering hops. Use for: Ales Aroma: Primarily for bittering Substitutions: Target, Northdown, Challenger", "Type": "Bittering", "Form": "Pellet", "Beta": 5.6, "HSI": 15.0, "Humulene": 0.0, "Caryophyllene": 0.0, "Cohumulone": 0.0, "Myrcene": 0.0, "Substitutes": ""} ,
{ "_id": { "$oid": "50ae677361d118e3646d7d6d"}, "Name": "Ahtanum", "Origin": "U.S.", "Alpha": 6.0, "Amount": 0.0, "Use": "Boil", "Time": 0.0, "Notes": "Distinctive aromatic hops with moderate bittering power from Washington. Use for: Distinctive aroma Substitutes: N/A", "Type": "Aroma", "Form": "Pellet", "Beta": 5.25, "HSI": 30.0, "Humulene": 0.0, "Caryophyllene": 0.0, "Cohumulone": 0.0, "Myrcene": 0.0, "Substitutes": ""} ,
{ "_id": { "$oid": "50ae677361d118e3646d7d6e"}, "Name": "Amarillo Gold", "Origin": "U.S.", "Alpha": 8.5, "Amount": 0.0, "Use": "Boil", "Time": 0.0, "Notes": "Unknown origin, but character similar to Cascade. Use for: IPAs, Ales Aroma: Citrus, Flowery Substitutions: Cascade, Centennial", "Type": "Aroma", "Form": "Pellet", "Beta": 6.0, "HSI": 25.0, "Humulene": 0.0, "Caryophyllene": 0.0, "Cohumulone": 0.0, "Myrcene": 0.0, "Substitutes": ""} ,
{ "_id": { "$oid": "50ae677361d118e3646d7d6f"}, "Name": "Aquila", "Origin": "U.S.", "Alpha": 6.5, "Amount": 0.0, "Use": "Boil", "Time": 0.0, "Notes": "Aroma hops developed in 1988. Limited use due to high cohumolone.Used for: Aroma hops Substitutes: ClusterNo longer commercially grown.", "Type": "Aroma", "Form": "Pellet", "Beta": 3.0, "HSI": 35.0, "Humulene": 0.0, "Caryophyllene": 0.0, "Cohumulone": 0.0, "Myrcene": 0.0, "Substitutes": ""} ,
{ "_id": { "$oid": "50ae677361d118e3646d7d70"}, "Name": "Auscha (Saaz)", "Origin": "Czech Republic", "Alpha": 3.3, "Amount": 0.0, "Use": "Boil", "Time": 0.0, "Notes": " Use for: Pilsners and Bohemian style lagers Aroma: Delicate, mild, clean, somewhat floral -- Noble hops Substitute: Tettnanger, LublinExamples: Pulsner Urquell", "Type": "Aroma", "Form": "Pellet", "Beta": 3.5, "HSI": 42.0, "Humulene": 0.0, "Caryophyllene": 0.0, "Cohumulone": 0.0, "Myrcene": 0.0, "Substitutes": ""} ,
];
// sends notification that data has been updated
var saveHop = function(hop) {
requestNotificationChannel.dataUpdated();
};
// removes the item from the array and sends a notification that data has been updated
var deleteHop = function(hop) {
for(var i = 0; i < hops.length; i++) {
if(hops[i]._id.$oid === hop._id.$oid) {
hops.splice(i, 1);
requestNotificationChannel.dataUpdated();
return;
}
};
};
// internal function to generate a random number guid generation
var S4 = function() {
return (((1+Math.random())*0x10000)|0).toString(16).substring(1);
};
// generates a guid for adding items to array
var guid = function () {
return (S4() + S4() + "-" + S4() + "-4" + S4().substr(0,3) + "-" + S4() + "-" + S4() + S4() + S4()).toLowerCase();
};
// function to add a hop to the array and sends a notification that data has been updated
var addHop = function(hop) {
hops.id.$oid = guid();
hops.push(hop);
requestNotificationChannel.dataUpdated();
};
// returns the array of hops
var getHops = function() {
return hops;
};
// returns a specific hop with the given id
var getHop = function(id) {
for(var i = 0; i < hops.length; i++) {
if(hops[i]._id.$oid === id) {
return hops[i];
}
};
};
// return the publicly accessible methods
return {
getHops: getHops,
getHop: getHop,
saveHop: saveHop,
deleteHop: deleteHop,
addHop: addHop
}
}]);