goog.provide('ol.Observable');
goog.require('ol.events');
goog.require('ol.events.EventTarget');
goog.require('ol.events.EventType');
/**
* @classdesc
* Abstract base class; normally only used for creating subclasses and not
* instantiated in apps.
* An event target providing convenient methods for listener registration
* and unregistration. A generic `change` event is always available through
* {@link ol.Observable#changed}.
*
* @constructor
* @extends {ol.events.EventTarget}
* @fires change
* @struct
* @api stable
*/
ol.Observable = function() {
goog.base(this);
/**
* @private
* @type {number}
*/
this.revision_ = 0;
};
goog.inherits(ol.Observable, ol.events.EventTarget);
/**
* Removes an event listener using the key returned by `on()` or `once()`.
* @param {ol.events.Key|Array.<ol.events.Key>} key The key returned by `on()`
* or `once()` (or an array of keys).
* @api stable
*/
ol.Observable.unByKey = function(key) {
Iif (Array.isArray(key)) {
for (var i = 0, ii = key.length; i < ii; ++i) {
ol.events.unlistenByKey(key[i]);
}
} else {
ol.events.unlistenByKey(/** @type {ol.events.Key} */ (key));
}
};
/**
* Increases the revision counter and dispatches a 'change' event.
* @api
*/
ol.Observable.prototype.changed = function() {
++this.revision_;
this.dispatchEvent(ol.events.EventType.CHANGE);
};
/**
* Triggered when the revision counter is increased.
* @event change
* @api
*/
/**
* Dispatches an event and calls all listeners listening for events
* of this type. The event parameter can either be a string or an
* Object with a `type` property.
*
* @param {{type: string,
* target: (EventTarget|ol.events.EventTarget|undefined)}|ol.events.Event|
* string} event Event object.
* @function
* @api
*/
ol.Observable.prototype.dispatchEvent;
/**
* Get the version number for this object. Each time the object is modified,
* its version number will be incremented.
* @return {number} Revision.
* @api
*/
ol.Observable.prototype.getRevision = function() {
return this.revision_;
};
/**
* Listen for a certain type of event.
* @param {string|Array.<string>} type The event type or array of event types.
* @param {function(?): ?} listener The listener function.
* @param {Object=} opt_this The object to use as `this` in `listener`.
* @return {ol.events.Key|Array.<ol.events.Key>} Unique key for the listener. If
* called with an array of event types as the first argument, the return
* will be an array of keys.
* @api stable
*/
ol.Observable.prototype.on = function(type, listener, opt_this) {
if (Array.isArray(type)) {
var len = type.length;
var keys = new Array(len);
for (var i = 0; i < len; ++i) {
keys[i] = ol.events.listen(this, type[i], listener, opt_this);
}
return keys;
} else {
return ol.events.listen(
this, /** @type {string} */ (type), listener, opt_this);
}
};
/**
* Listen once for a certain type of event.
* @param {string|Array.<string>} type The event type or array of event types.
* @param {function(?): ?} listener The listener function.
* @param {Object=} opt_this The object to use as `this` in `listener`.
* @return {ol.events.Key|Array.<ol.events.Key>} Unique key for the listener. If
* called with an array of event types as the first argument, the return
* will be an array of keys.
* @api stable
*/
ol.Observable.prototype.once = function(type, listener, opt_this) {
if (Array.isArray(type)) {
var len = type.length;
var keys = new Array(len);
for (var i = 0; i < len; ++i) {
keys[i] = ol.events.listenOnce(this, type[i], listener, opt_this);
}
return keys;
} else {
return ol.events.listenOnce(
this, /** @type {string} */ (type), listener, opt_this);
}
};
/**
* Unlisten for a certain type of event.
* @param {string|Array.<string>} type The event type or array of event types.
* @param {function(?): ?} listener The listener function.
* @param {Object=} opt_this The object which was used as `this` by the
* `listener`.
* @api stable
*/
ol.Observable.prototype.un = function(type, listener, opt_this) {
Iif (Array.isArray(type)) {
for (var i = 0, ii = type.length; i < ii; ++i) {
ol.events.unlisten(this, type[i], listener, opt_this);
}
return;
} else {
ol.events.unlisten(this, /** @type {string} */ (type), listener, opt_this);
}
};
/**
* Removes an event listener using the key returned by `on()` or `once()`.
* Note that using the {@link ol.Observable.unByKey} static function is to
* be preferred.
* @param {ol.events.Key|Array.<ol.events.Key>} key The key returned by `on()`
* or `once()` (or an array of keys).
* @function
* @api stable
*/
ol.Observable.prototype.unByKey = ol.Observable.unByKey;
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