openlayers
Version:
Build tools and sources for developing OpenLayers based mapping applications
238 lines (206 loc) • 6.49 kB
JavaScript
goog.provide('ol.Object');
goog.require('ol');
goog.require('ol.Observable');
goog.require('ol.events.Event');
goog.require('ol.obj');
/**
* @classdesc
* Abstract base class; normally only used for creating subclasses and not
* instantiated in apps.
* Most non-trivial classes inherit from this.
*
* This extends {@link ol.Observable} with observable properties, where each
* property is observable as well as the object as a whole.
*
* Classes that inherit from this have pre-defined properties, to which you can
* add your owns. The pre-defined properties are listed in this documentation as
* 'Observable Properties', and have their own accessors; for example,
* {@link ol.Map} has a `target` property, accessed with `getTarget()` and
* changed with `setTarget()`. Not all properties are however settable. There
* are also general-purpose accessors `get()` and `set()`. For example,
* `get('target')` is equivalent to `getTarget()`.
*
* The `set` accessors trigger a change event, and you can monitor this by
* registering a listener. For example, {@link ol.View} has a `center`
* property, so `view.on('change:center', function(evt) {...});` would call the
* function whenever the value of the center property changes. Within the
* function, `evt.target` would be the view, so `evt.target.getCenter()` would
* return the new center.
*
* You can add your own observable properties with
* `object.set('prop', 'value')`, and retrieve that with `object.get('prop')`.
* You can listen for changes on that property value with
* `object.on('change:prop', listener)`. You can get a list of all
* properties with {@link ol.Object#getProperties object.getProperties()}.
*
* Note that the observable properties are separate from standard JS properties.
* You can, for example, give your map object a title with
* `map.title='New title'` and with `map.set('title', 'Another title')`. The
* first will be a `hasOwnProperty`; the second will appear in
* `getProperties()`. Only the second is observable.
*
* Properties can be deleted by using the unset method. E.g.
* object.unset('foo').
*
* @constructor
* @extends {ol.Observable}
* @param {Object.<string, *>=} opt_values An object with key-value pairs.
* @fires ol.Object.Event
* @api
*/
ol.Object = function(opt_values) {
ol.Observable.call(this);
// Call ol.getUid to ensure that the order of objects' ids is the same as
// the order in which they were created. This also helps to ensure that
// object properties are always added in the same order, which helps many
// JavaScript engines generate faster code.
ol.getUid(this);
/**
* @private
* @type {!Object.<string, *>}
*/
this.values_ = {};
if (opt_values !== undefined) {
this.setProperties(opt_values);
}
};
ol.inherits(ol.Object, ol.Observable);
/**
* @private
* @type {Object.<string, string>}
*/
ol.Object.changeEventTypeCache_ = {};
/**
* @param {string} key Key name.
* @return {string} Change name.
*/
ol.Object.getChangeEventType = function(key) {
return ol.Object.changeEventTypeCache_.hasOwnProperty(key) ?
ol.Object.changeEventTypeCache_[key] :
(ol.Object.changeEventTypeCache_[key] = 'change:' + key);
};
/**
* Gets a value.
* @param {string} key Key name.
* @return {*} Value.
* @api stable
*/
ol.Object.prototype.get = function(key) {
var value;
if (this.values_.hasOwnProperty(key)) {
value = this.values_[key];
}
return value;
};
/**
* Get a list of object property names.
* @return {Array.<string>} List of property names.
* @api stable
*/
ol.Object.prototype.getKeys = function() {
return Object.keys(this.values_);
};
/**
* Get an object of all property names and values.
* @return {Object.<string, *>} Object.
* @api stable
*/
ol.Object.prototype.getProperties = function() {
return ol.obj.assign({}, this.values_);
};
/**
* @param {string} key Key name.
* @param {*} oldValue Old value.
*/
ol.Object.prototype.notify = function(key, oldValue) {
var eventType;
eventType = ol.Object.getChangeEventType(key);
this.dispatchEvent(new ol.Object.Event(eventType, key, oldValue));
eventType = ol.Object.EventType.PROPERTYCHANGE;
this.dispatchEvent(new ol.Object.Event(eventType, key, oldValue));
};
/**
* Sets a value.
* @param {string} key Key name.
* @param {*} value Value.
* @param {boolean=} opt_silent Update without triggering an event.
* @api stable
*/
ol.Object.prototype.set = function(key, value, opt_silent) {
if (opt_silent) {
this.values_[key] = value;
} else {
var oldValue = this.values_[key];
this.values_[key] = value;
if (oldValue !== value) {
this.notify(key, oldValue);
}
}
};
/**
* Sets a collection of key-value pairs. Note that this changes any existing
* properties and adds new ones (it does not remove any existing properties).
* @param {Object.<string, *>} values Values.
* @param {boolean=} opt_silent Update without triggering an event.
* @api stable
*/
ol.Object.prototype.setProperties = function(values, opt_silent) {
var key;
for (key in values) {
this.set(key, values[key], opt_silent);
}
};
/**
* Unsets a property.
* @param {string} key Key name.
* @param {boolean=} opt_silent Unset without triggering an event.
* @api stable
*/
ol.Object.prototype.unset = function(key, opt_silent) {
if (key in this.values_) {
var oldValue = this.values_[key];
delete this.values_[key];
if (!opt_silent) {
this.notify(key, oldValue);
}
}
};
/**
* @enum {string}
*/
ol.Object.EventType = {
/**
* Triggered when a property is changed.
* @event ol.Object.Event#propertychange
* @api stable
*/
PROPERTYCHANGE: 'propertychange'
};
/**
* @classdesc
* Events emitted by {@link ol.Object} instances are instances of this type.
*
* @param {string} type The event type.
* @param {string} key The property name.
* @param {*} oldValue The old value for `key`.
* @extends {ol.events.Event}
* @implements {oli.Object.Event}
* @constructor
*/
ol.Object.Event = function(type, key, oldValue) {
ol.events.Event.call(this, type);
/**
* The name of the property whose value is changing.
* @type {string}
* @api stable
*/
this.key = key;
/**
* The old value. To get the new value use `e.target.get(e.key)` where
* `e` is the event object.
* @type {*}
* @api stable
*/
this.oldValue = oldValue;
};
ol.inherits(ol.Object.Event, ol.events.Event);