WIP build up displaysets.

extensions/default/src/DicomWebDataSource/wado/retrieveMetadataLoader.js

@@ -0,0 +1,59 @@
+/**
+ * Class to define inheritance of load retrieve strategy.
+ * The process can be async load (lazy) or sync load
+ *
+ * There are methods that must be implemented at consumer level
+ * To retrieve study call execLoad
+ */
+export default class RetrieveMetadataLoader {
+  /**
+   * @constructor
+   * @param {Object} client The dicomweb-client.
+   * @param {Array} studyInstanceUID Study instance ui to be retrieved
+   * @param {Object} [filters] - Object containing filters to be applied on retrieve metadata process
+   * @param {string} [filter.seriesInstanceUID] - series instance uid to filter results against
+   */
+  constructor(client, studyInstanceUID, filters = {}) {
+    this.client = dicomwWebClient;
+    this.studyInstanceUID = studyInstanceUID;
+    this.filters = filters;
+  }
+
+  async execLoad() {
+    const preLoadData = await this.preLoad();
+    const loadData = await this.load(preLoadData);
+    const postLoadData = await this.posLoad(loadData);
+
+    return postLoadData;
+  }
+
+  /**
+   * It iterates over given loaders running each one. Loaders parameters must be bind when getting it.
+   * @param {Array} loaders - array of loader to retrieve data.
+   */
+  async runLoaders(loaders) {
+    let result;
+    for (const loader of loaders) {
+      try {
+        result = await loader();
+        if (result && result.length) {
+          break; // closes iterator in case data is retrieved successfully
+        }
+      } catch (e) {
+        throw e;
+      }
+    }
+
+    if (loaders.next().done && !result) {
+      throw new Error('RetrieveMetadataLoader failed');
+    }
+
+    return result;
+  }
+
+  // Methods to be overwrite
+  async configLoad() {}
+  async preLoad() {}
+  async load(preLoadData) {}
+  async posLoad(loadData) {}
+}