Add method for retrieving ol.Overlay by id

src/ol/overlay.js

@@ -19,6 +19,7 @@ goog.require('ol.extent');
  * @enum {string}
  */
 ol.OverlayProperty = {
+  ID: 'id',
   ELEMENT: 'element',
   MAP: 'map',
   OFFSET: 'offset',
@@ -73,6 +74,12 @@ ol.Overlay = function(options) {
 
   goog.base(this);
 
+  /**
+   * @private
+   * @type {number|string|undefined}
+   */
+  this.id_ = undefined;
+
   /**
    * @private
    * @type {boolean}
@@ -187,6 +194,17 @@ ol.Overlay.prototype.getElement = function() {
 };
 
 
+/**
+ * Get the feature identifier.  This is an identifier for the overlay and
+ * is set explicitly by calling {@link ol.Overlay#setId}.
+ * @return {number|string|undefined} Id.
+ * @api
+ */
+ol.Overlay.prototype.getId = function() {
+  return this.id_;
+};
+
+
 /**
  * Get the map associated with this overlay.
  * @return {ol.Map|undefined} The map that the overlay is part of.
@@ -211,6 +229,15 @@ ol.Overlay.prototype.getOffset = function() {
 };
 
 
+/**
+ * Workaround to overcome circular dependency.
+ * @return {ol.OverlayProperty}
+ */
+ol.Overlay.prototype.getOverlayIdProperty = function() {
+  return ol.OverlayProperty.ID;
+};
+
+
 /**
  * Get the current position of this overlay.
  * @return {ol.Coordinate|undefined} The spatial point that the overlay is
@@ -321,6 +348,22 @@ ol.Overlay.prototype.setElement = function(element) {
 };
 
 
+/**
+ * Set the feature id. The feature id can be used with the
+ * {@link ol.Map#getOverlayById} method.
+ * @param {number|string} id The feature id.
+ * @observable
+ * @api
+ */
+ol.Overlay.prototype.setId = function(id) {
+  goog.asserts.assert(id !== undefined, 'overlay id should be defined');
+  if (id != this.id_) {
+    this.id_ = id;
+    this.set(ol.OverlayProperty.ID, id);
+  }
+};
+
+
 /**
  * Set the map to be associated with this overlay.
  * @param {ol.Map|undefined} map The map that the overlay is part of.