Class Ember.Engine
publicThe Engine
class contains core functionality for both applications and
engines.
Each engine manages a registry that's used for dependency injection and
exposed through RegistryProxy
.
Engines also manage initializers and instance initializers.
Engines can spawn EngineInstance
instances via buildInstance()
.
addObserver (key, target, method) public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:333
- key
- String
- The key to observer
- target
- Object
- The target object to invoke
- method
- String|Function
- The method to invoke.
Adds an observer on a property.
This is the core method used to register an observer for a property.
Once you call this method, any time the key's value is set, your observer will be notified. Note that the observers are triggered any time the value is set, regardless of whether it has actually changed. Your observer should be prepared to handle that.
You can also pass an optional context parameter to this method. The context will be passed to your observer method whenever it is triggered. Note that if you add the same target/method pair on a key multiple times with different context parameters, your observer will only be called once with the last context you passed.
Observer Methods
Observer methods you pass should generally have the following signature if
you do not pass a context
parameter:
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fooDidChange: function(sender, key, value, rev) { }; |
The sender is the object that changed. The key is the property that changes. The value property is currently reserved and unused. The rev is the last property revision of the object when it changed, which you can use to detect if the key value has really changed or not.
If you pass a context
parameter, the context will be passed before the
revision like so:
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fooDidChange: function(sender, key, value, context, rev) { }; |
Usually you will not need the value, context or revision parameters at the end. In this case, it is common to write observer methods that take only a sender and key value as parameters or, if you aren't interested in any of these values, to write an observer that has no parameters at all.
cacheFor (keyName) Object public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:490
- keyName
- String
- returns
- Object
- The cached value of the computed property, if any
Returns the cached value of a computed property, if it exists. This allows you to inspect the value of a computed property without accidentally invoking it if it is intended to be generated lazily.
create (arguments) public
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:635
- arguments
Creates an instance of a class. Accepts either no arguments, or an object containing values to initialize the newly instantiated object with.
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App.Person = Ember.Object.extend({ helloWorld: function() { alert("Hi, my name is " + this.get('name')); } }); var tom = App.Person.create({ name: 'Tom Dale' }); tom.helloWorld(); // alerts "Hi, my name is Tom Dale". |
create
will call the init
function if defined during
Ember.AnyObject.extend
If no arguments are passed to create
, it will not set values to the new
instance during initialization:
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var noName = App.Person.create(); noName.helloWorld(); // alerts undefined |
NOTE: For performance reasons, you cannot declare methods or computed
properties during create
. You should instead declare methods and computed
properties when using extend
.
decrementProperty (keyName, decrement) Number public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:453
- keyName
- String
- The name of the property to decrement
- decrement
- Number
- The amount to decrement by. Defaults to 1
- returns
- Number
- The new property value
Set the value of a property to the current value minus some amount.
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player.decrementProperty('lives'); orc.decrementProperty('health', 5); |
destroy Ember.Object public
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:417
- returns
- Ember.Object
- receiver
Destroys an object by setting the isDestroyed
flag and removing its
metadata, which effectively destroys observers and bindings.
If you try to set a property on a destroyed object, an exception will be raised.
Note that destruction is scheduled for the end of the run loop and does not happen immediately. It will set an isDestroying flag immediately.
extend (mixins, arguments) public
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:527
- mixins
- Mixin
- One or more Mixin classes
- arguments
- Object
- Object containing values to use within the new class
Creates a new subclass.
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App.Person = Ember.Object.extend({ say: function(thing) { alert(thing); } }); |
This defines a new subclass of Ember.Object: App.Person
. It contains one method: say()
.
You can also create a subclass from any existing class by calling its extend()
method.
For example, you might want to create a subclass of Ember's built-in Ember.View
class:
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App.PersonView = Ember.View.extend({ tagName: 'li', classNameBindings: ['isAdministrator'] }); |
When defining a subclass, you can override methods but still access the
implementation of your parent class by calling the special _super()
method:
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App.Person = Ember.Object.extend({ say: function(thing) { var name = this.get('name'); alert(name + ' says: ' + thing); } }); App.Soldier = App.Person.extend({ say: function(thing) { this._super(thing + ", sir!"); }, march: function(numberOfHours) { alert(this.get('name') + ' marches for ' + numberOfHours + ' hours.'); } }); var yehuda = App.Soldier.create({ name: "Yehuda Katz" }); yehuda.say("Yes"); // alerts "Yehuda Katz says: Yes, sir!" |
The create()
on line #17 creates an instance of the App.Soldier
class.
The extend()
on line #8 creates a subclass of App.Person
. Any instance
of the App.Person
class will not have the march()
method.
You can also pass Mixin
classes to add additional properties to the subclass.
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App.Person = Ember.Object.extend({ say: function(thing) { alert(this.get('name') + ' says: ' + thing); } }); App.SingingMixin = Mixin.create({ sing: function(thing){ alert(this.get('name') + ' sings: la la la ' + thing); } }); App.BroadwayStar = App.Person.extend(App.SingingMixin, { dance: function() { alert(this.get('name') + ' dances: tap tap tap tap '); } }); |
The App.BroadwayStar
class contains three methods: say()
, sing()
, and dance()
.
get (keyName) Object public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:100
- keyName
- String
- The property to retrieve
- returns
- Object
- The property value or undefined.
Retrieves the value of a property from the object.
This method is usually similar to using object[keyName]
or object.keyName
,
however it supports both computed properties and the unknownProperty
handler.
Because get
unifies the syntax for accessing all these kinds
of properties, it can make many refactorings easier, such as replacing a
simple property with a computed property, or vice versa.
Computed Properties
Computed properties are methods defined with the property
modifier
declared at the end, such as:
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fullName: function() { return this.get('firstName') + ' ' + this.get('lastName'); }.property('firstName', 'lastName') |
When you call get
on a computed property, the function will be
called and the return value will be returned instead of the function
itself.
Unknown Properties
Likewise, if you try to call get
on a property whose value is
undefined
, the unknownProperty()
method will be called on the object.
If this method returns any value other than undefined
, it will be returned
instead. This allows you to implement "virtual" properties that are
not defined upfront.
getProperties (list) Object public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:143
- list
- String...|Array
- of keys to get
- returns
- Object
To get the values of multiple properties at once, call getProperties
with a list of strings or an array:
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record.getProperties('firstName', 'lastName', 'zipCode'); // { firstName: 'John', lastName: 'Doe', zipCode: '10011' } |
is equivalent to:
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record.getProperties(['firstName', 'lastName', 'zipCode']); // { firstName: 'John', lastName: 'Doe', zipCode: '10011' } |
getWithDefault (keyName, defaultValue) Object public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:415
- keyName
- String
- The name of the property to retrieve
- defaultValue
- Object
- The value to return if the property value is undefined
- returns
- Object
- The property value or the defaultValue.
Retrieves the value of a property, or a default value in the case that the
property returns undefined
.
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person.getWithDefault('lastName', 'Doe'); |
incrementProperty (keyName, increment) Number public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:433
- keyName
- String
- The name of the property to increment
- increment
- Number
- The amount to increment by. Defaults to 1
- returns
- Number
- The new property value
Set the value of a property to the current value plus some amount.
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person.incrementProperty('age'); team.incrementProperty('score', 2); |
init public
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:217
An overridable method called when objects are instantiated. By default, does nothing unless it is overridden during class definition.
Example:
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App.Person = Ember.Object.extend({ init: function() { alert('Name is ' + this.get('name')); } }); var steve = App.Person.create({ name: "Steve" }); // alerts 'Name is Steve'. |
NOTE: If you do override init
for a framework class like Ember.View
,
be sure to call this._super(...arguments)
in your
init
declaration! If you don't, Ember may not have an opportunity to
do important setup work, and you'll see strange behavior in your
application.
initializer (initializer) public
Defined in packages/ember-application/lib/system/engine.js:185
- initializer
- Object
The goal of initializers should be to register dependencies and injections. This phase runs once. Because these initializers may load code, they are allowed to defer application readiness and advance it. If you need to access the container or store you should use an InstanceInitializer that will be run after all initializers and therefore after all code is loaded and the app is ready.
Initializer receives an object which has the following attributes:
name
, before
, after
, initialize
. The only required attribute is
initialize
, all others are optional.
name
allows you to specify under which name the initializer is registered. This must be a unique name, as trying to register two initializers with the same name will result in an error.
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Ember.Application.initializer({ name: 'namedInitializer', initialize: function(application) { Ember.debug('Running namedInitializer!'); } }); |
before
andafter
are used to ensure that this initializer is ran prior or after the one identified by the value. This value can be a single string or an array of strings, referencing thename
of other initializers.
An example of ordering initializers, we create an initializer named first
:
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Ember.Application.initializer({ name: 'first', initialize: function(application) { Ember.debug('First initializer!'); } }); // DEBUG: First initializer! |
We add another initializer named second
, specifying that it should run
after the initializer named first
:
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Ember.Application.initializer({ name: 'second', after: 'first', initialize: function(application) { Ember.debug('Second initializer!'); } }); // DEBUG: First initializer! // DEBUG: Second initializer! |
Afterwards we add a further initializer named pre
, this time specifying
that it should run before the initializer named first
:
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Ember.Application.initializer({ name: 'pre', before: 'first', initialize: function(application) { Ember.debug('Pre initializer!'); } }); // DEBUG: Pre initializer! // DEBUG: First initializer! // DEBUG: Second initializer! |
Finally we add an initializer named post
, specifying it should run after
both the first
and the second
initializers:
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Ember.Application.initializer({ name: 'post', after: ['first', 'second'], initialize: function(application) { Ember.debug('Post initializer!'); } }); // DEBUG: Pre initializer! // DEBUG: First initializer! // DEBUG: Second initializer! // DEBUG: Post initializer! |
initialize
is a callback function that receives one argument,application
, on which you can operate.
Example of using application
to register an adapter:
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Ember.Application.initializer({ name: 'api-adapter', initialize: function(application) { application.register('api-adapter:main', ApiAdapter); } }); |
instanceInitializer (instanceInitializer) public
Defined in packages/ember-application/lib/system/engine.js:305
- instanceInitializer
Instance initializers run after all initializers have run. Because instance initializers run after the app is fully set up. We have access to the store, container, and other items. However, these initializers run after code has loaded and are not allowed to defer readiness.
Instance initializer receives an object which has the following attributes:
name
, before
, after
, initialize
. The only required attribute is
initialize
, all others are optional.
name
allows you to specify under which name the instanceInitializer is registered. This must be a unique name, as trying to register two instanceInitializer with the same name will result in an error.
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Ember.Application.instanceInitializer({ name: 'namedinstanceInitializer', initialize: function(application) { Ember.debug('Running namedInitializer!'); } }); |
before
andafter
are used to ensure that this initializer is ran prior or after the one identified by the value. This value can be a single string or an array of strings, referencing thename
of other initializers.See Ember.Application.initializer for discussion on the usage of before and after.
Example instanceInitializer to preload data into the store.
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Ember.Application.initializer({ name: 'preload-data', initialize: function(application) { var userConfig, userConfigEncoded, store; // We have a HTML escaped JSON representation of the user's basic // configuration generated server side and stored in the DOM of the main // index.html file. This allows the app to have access to a set of data // without making any additional remote calls. Good for basic data that is // needed for immediate rendering of the page. Keep in mind, this data, // like all local models and data can be manipulated by the user, so it // should not be relied upon for security or authorization. // // Grab the encoded data from the meta tag userConfigEncoded = Ember.$('head meta[name=app-user-config]').attr('content'); // Unescape the text, then parse the resulting JSON into a real object userConfig = JSON.parse(unescape(userConfigEncoded)); // Lookup the store store = application.lookup('service:store'); // Push the encoded JSON into the store store.pushPayload(userConfig); } }); |
notifyPropertyChange (keyName) Ember.Observable public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:318
- keyName
- String
- The property key to be notified about.
- returns
- Ember.Observable
Convenience method to call propertyWillChange
and propertyDidChange
in
succession.
removeObserver (key, target, method) public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:385
- key
- String
- The key to observer
- target
- Object
- The target object to invoke
- method
- String|Function
- The method to invoke.
Remove an observer you have previously registered on this object. Pass
the same key, target, and method you passed to addObserver()
and your
target will no longer receive notifications.
reopen public
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:681
Augments a constructor's prototype with additional properties and functions:
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MyObject = Ember.Object.extend({ name: 'an object' }); o = MyObject.create(); o.get('name'); // 'an object' MyObject.reopen({ say: function(msg){ console.log(msg); } }) o2 = MyObject.create(); o2.say("hello"); // logs "hello" o.say("goodbye"); // logs "goodbye" |
To add functions and properties to the constructor itself,
see reopenClass
reopenClass public
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:717
Augments a constructor's own properties and functions:
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MyObject = Ember.Object.extend({ name: 'an object' }); MyObject.reopenClass({ canBuild: false }); MyObject.canBuild; // false o = MyObject.create(); |
In other words, this creates static properties and functions for the class. These are only available on the class and not on any instance of that class.
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App.Person = Ember.Object.extend({ name : "", sayHello : function() { alert("Hello. My name is " + this.get('name')); } }); App.Person.reopenClass({ species : "Homo sapiens", createPerson: function(newPersonsName){ return App.Person.create({ name:newPersonsName }); } }); var tom = App.Person.create({ name : "Tom Dale" }); var yehuda = App.Person.createPerson("Yehuda Katz"); tom.sayHello(); // "Hello. My name is Tom Dale" yehuda.sayHello(); // "Hello. My name is Yehuda Katz" alert(App.Person.species); // "Homo sapiens" |
Note that species
and createPerson
are not valid on the tom
and yehuda
variables. They are only valid on App.Person
.
To add functions and properties to instances of
a constructor by extending the constructor's prototype
see reopen
set (keyName, value) Object public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:168
- keyName
- String
- The property to set
- value
- Object
- The value to set or `null`.
- returns
- Object
- The passed value
Sets the provided key or path to the value.
This method is generally very similar to calling object[key] = value
or
object.key = value
, except that it provides support for computed
properties, the setUnknownProperty()
method and property observers.
Computed Properties
If you try to set a value on a key that has a computed property handler
defined (see the get()
method for an example), then set()
will call
that method, passing both the value and key instead of simply changing
the value itself. This is useful for those times when you need to
implement a property that is composed of one or more member
properties.
Unknown Properties
If you try to set a value on a key that is undefined in the target
object, then the setUnknownProperty()
handler will be called instead. This
gives you an opportunity to implement complex "virtual" properties that
are not predefined on the object. If setUnknownProperty()
returns
undefined, then set()
will simply set the value on the object.
Property Observers
In addition to changing the property, set()
will also register a property
change with the object. Unless you have placed this call inside of a
beginPropertyChanges()
and endPropertyChanges(),
any "local" observers
(i.e. observer methods declared on the same object), will be called
immediately. Any "remote" observers (i.e. observer methods declared on
another object) will be placed in a queue and called at a later time in a
coalesced manner.
setProperties (hash) Object public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:213
- hash
- Object
- the hash of keys and values to set
- returns
- Object
- The passed in hash
Sets a list of properties at once. These properties are set inside
a single beginPropertyChanges
and endPropertyChanges
batch, so
observers will be buffered.
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record.setProperties({ firstName: 'Charles', lastName: 'Jolley' }); |
toString String public
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:467
- returns
- String
- string representation
Returns a string representation which attempts to provide more information
than Javascript's toString
typically does, in a generic way for all Ember
objects.
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App.Person = Em.Object.extend() person = App.Person.create() person.toString() //=> "<App.Person:ember1024>" |
If the object's class is not defined on an Ember namespace, it will indicate it is a subclass of the registered superclass:
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Student = App.Person.extend() student = Student.create() student.toString() //=> "<(subclass of App.Person):ember1025>" |
If the method toStringExtension
is defined, its return value will be
included in the output.
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App.Teacher = App.Person.extend({ toStringExtension: function() { return this.get('fullName'); } }); teacher = App.Teacher.create() teacher.toString(); //=> "<App.Teacher:ember1026:Tom Dale>" |
toggleProperty (keyName) Boolean public
Inherited from Ember.Observable packages/ember-runtime/lib/mixins/observable.js:473
- keyName
- String
- The name of the property to toggle
- returns
- Boolean
- The new property value
Set the value of a boolean property to the opposite of its current value.
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starship.toggleProperty('warpDriveEngaged'); |
willDestroy public
Inherited from Ember.CoreObject packages/ember-runtime/lib/system/core_object.js:440
Override to implement teardown.