Accept simpler attributions in sources

src/ol/source/source.js

@@ -21,7 +21,7 @@ ol.source.State = {
 
 
 /**
- * @typedef {{attributions: (Array.<ol.Attribution>|undefined),
+ * @typedef {{attributions: (olx.source.AttributionOption|undefined),
  *            logo: (string|olx.LogoOptions|undefined),
  *            projection: ol.proj.ProjectionLike,
  *            state: (ol.source.State|undefined),
@@ -57,8 +57,7 @@ ol.source.Source = function(options) {
    * @private
    * @type {Array.<ol.Attribution>}
    */
-  this.attributions_ = options.attributions !== undefined ?
-      options.attributions : null;
+  this.attributions_ = ol.source.Source.toAttributionsArray_(options.attributions);
 
   /**
    * @private
@@ -82,6 +81,37 @@ ol.source.Source = function(options) {
 };
 goog.inherits(ol.source.Source, ol.Object);
 
+/**
+ * Turns various ways of defining an attribution to an array of `ol.Attributions`.
+ *
+ * @param {olx.source.AttributionOption|undefined}
+ *     attributionLike The attributions as string, array of strings,
+ *     `ol.Attribution`, array of `ol.Attribution` or undefined.
+ * @return {Array.<ol.Attribution>} The array of `ol.Attribution` or null if
+ *     `undefined` was given.
+ */
+ol.source.Source.toAttributionsArray_ = function(attributionLike) {
+  if (typeof attributionLike === 'string') {
+    return [new ol.Attribution({html: attributionLike})];
+  } else if (attributionLike instanceof ol.Attribution) {
+    return [attributionLike];
+  } else if (Array.isArray(attributionLike)) {
+    var len = attributionLike.length;
+    var attributions = new Array(len);
+    for (var i = 0; i < len; i++) {
+      var item = attributionLike[i];
+      if (typeof item === 'string') {
+        attributions[i] = new ol.Attribution({html: item});
+      } else {
+        attributions[i] = item;
+      }
+    }
+    return attributions;
+  } else {
+    return null;
+  }
+}
+
 
 /**
  * @param {ol.Coordinate} coordinate Coordinate.
@@ -161,11 +191,13 @@ ol.source.Source.prototype.refresh = function() {
 
 /**
  * Set the attributions of the source.
- * @param {Array.<ol.Attribution>} attributions Attributions.
+ * @param {olx.source.AttributionOption|undefined} attributions Attributions.
+ *     Can be passed as `string`, `Array<string>`, `{@link ol.Attribution}`,
+ *     `Array<{@link ol.Attribution}>` or `undefined`.
  * @api
  */
 ol.source.Source.prototype.setAttributions = function(attributions) {
-  this.attributions_ = attributions;
+  this.attributions_ = ol.source.Source.toAttributionsArray_(attributions);
   this.changed();
 };