Add base loader class

Author: ivmartel

src/io/dicomDataLoader.js

@@ -3,43 +3,12 @@ import {getUrlFromUri} from '../utils/uri.js';
 import {fileContentTypes} from './filesLoader.js';
 import {urlContentTypes} from './urlsLoader.js';
 import {DicomBufferToData} from '../image/dicomBufferToData.js';
+import {LoaderBase} from './loaderBase.js';
 
 /**
  * DICOM data loader.
  */
-export class DicomDataLoader {
-
-  /**
-   * Loader options.
-   *
-   * @type {object}
-   */
-  #options = {};
-
-  /**
-   * Loading flag.
-   *
-   * @type {boolean}
-   */
-  #isLoading = false;
-
-  /**
-   * Set the loader options.
-   *
-   * @param {object} opt The input options.
-   */
-  setOptions(opt) {
-    this.#options = opt;
-  }
-
-  /**
-   * Is the load ongoing?
-   *
-   * @returns {boolean} True if loading.
-   */
-  isLoading() {
-    return this.#isLoading;
-  }
+export class DicomDataLoader extends LoaderBase {
 
   /**
    * DICOM buffer to Data (asynchronous).
@@ -56,17 +25,17 @@ export class DicomDataLoader {
    */
   load(buffer, origin, index) {
     // setup db2d ony once
-    if (!this.#isLoading) {
+    if (!this.isLoading()) {
       // pass options
-      this.#db2d.setOptions(this.#options);
+      this.#db2d.setOptions(this.getOptions());
       // connect handlers
       this.#db2d.onloadstart = this.onloadstart;
       this.#db2d.onprogress = this.onprogress;
       this.#db2d.onloaditem = this.onloaditem;
       this.#db2d.onload = this.onload;
       this.#db2d.onloadend = (event) => {
         // reset loading flag
-        this.#isLoading = false;
+        this.setLoading(false);
         // call listeners
         this.onloadend(event);
       };
@@ -78,7 +47,7 @@ export class DicomDataLoader {
     }
 
     // set loading flag
-    this.#isLoading = true;
+    this.setLoading(true);
     // convert
     this.#db2d.convert(buffer, origin, index);
   }
@@ -88,7 +57,7 @@ export class DicomDataLoader {
    */
   abort() {
     // reset loading flag
-    this.#isLoading = false;
+    this.setLoading(false);
     // abort conversion, will trigger db2d.onabort
     this.#db2d.abort();
   }
@@ -196,62 +165,4 @@ export class DicomDataLoader {
     return urlContentTypes.ArrayBuffer;
   }
 
-  /**
-   * Handle a load start event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load start event.
-   */
-  onloadstart(_event) {}
-
-  /**
-   * Handle a progress event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load progress event.
-   */
-  onprogress(_event) {}
-
-  /**
-   * Handle a load item event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load item event fired
-   *   when a file item has been loaded successfully.
-   */
-  onloaditem(_event) {}
-
-  /**
-   * Handle a load event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load event fired
-   *   when a file has been loaded successfully.
-   */
-  onload(_event) {}
-
-  /**
-   * Handle an load end event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load end event fired
-   *  when a file load has completed, successfully or not.
-   */
-  onloadend(_event) {}
-
-  /**
-   * Handle an error event.
-   * Default does nothing.
-   *
-   * @param {object} _event The error event.
-   */
-  onerror(_event) {}
-  /**
-   * Handle an abort event.
-   * Default does nothing.
-   *
-   * @param {object} _event The abort event.
-   */
-  onabort(_event) {}
-
 } // class DicomDataLoader

src/io/jsonTextLoader.js

@@ -2,36 +2,12 @@ import {startsWith, getFileExtension} from '../utils/string.js';
 import {getUrlFromUri} from '../utils/uri.js';
 import {fileContentTypes} from './filesLoader.js';
 import {urlContentTypes} from './urlsLoader.js';
+import {LoaderBase} from './loaderBase.js';
 
 /**
  * JSON text loader.
  */
-export class JSONTextLoader {
-
-  /**
-   * Loading flag.
-   *
-   * @type {boolean}
-   */
-  #isLoading = false;
-
-  /**
-   * Set the loader options.
-   *
-   * @param {object} _opt The input options.
-   */
-  setOptions(_opt) {
-    // does nothing
-  }
-
-  /**
-   * Is the load ongoing?
-   *
-   * @returns {boolean} True if loading.
-   */
-  isLoading() {
-    return this.#isLoading;
-  }
+export class JSONTextLoader extends LoaderBase {
 
   /**
    * Load data.
@@ -42,7 +18,7 @@ export class JSONTextLoader {
    */
   load(text, origin, index) {
     // set loading flag
-    this.#isLoading = true;
+    this.setLoading(true);
     this.onloadstart({
       source: origin
     });
@@ -69,7 +45,7 @@ export class JSONTextLoader {
       });
     } finally {
       // reset loading flag
-      this.#isLoading = false;
+      this.setLoading(false);
       this.onloadend({
         source: origin
       });
@@ -81,7 +57,7 @@ export class JSONTextLoader {
    */
   abort() {
     // reset loading flag
-    this.#isLoading = false;
+    this.setLoading(false);
     // call listeners
     this.onabort({});
     this.onloadend({});
@@ -175,63 +151,4 @@ export class JSONTextLoader {
     return urlContentTypes.Text;
   }
 
-  /**
-   * Handle a load start event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load start event.
-   */
-  onloadstart(_event) {}
-
-  /**
-   * Handle a progress event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load progress event.
-   */
-  onprogress(_event) {}
-
-  /**
-   * Handle a load item event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load item event fired
-   *   when a file item has been loaded successfully.
-   */
-  onloaditem(_event) {}
-
-  /**
-   * Handle a load event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load event fired
-   *   when a file has been loaded successfully.
-   */
-  onload(_event) {}
-
-  /**
-   * Handle an load end event.
-   * Default does nothing.
-   *
-   * @param {object} _event The load end event fired
-   *  when a file load has completed, successfully or not.
-   */
-  onloadend(_event) {}
-
-  /**
-   * Handle an error event.
-   * Default does nothing.
-   *
-   * @param {object} _event The error event.
-   */
-  onerror(_event) {}
-
-  /**
-   * Handle an abort event.
-   * Default does nothing.
-   *
-   * @param {object} _event The abort event.
-   */
-  onabort(_event) {}
-
 } // class JSONTextLoader

src/io/loaderBase.js

@@ -0,0 +1,119 @@
+/**
+ * Base class for single data loaders.
+ *
+ * Provides shared state (#options, #isLoading) and the seven
+ * event-handler stubs that the orchestrators (FilesLoader, UrlsLoader)
+ * assign per-instance before calling load().
+ */
+export class LoaderBase {
+
+  /**
+   * Loader options.
+   *
+   * @type {object}
+   */
+  #options = {};
+
+  /**
+   * Loading flag.
+   *
+   * @type {boolean}
+   */
+  #isLoading = false;
+
+  /**
+   * Get the loader options.
+   *
+   * @returns {object} The loader options.
+   */
+  getOptions() {
+    return this.#options;
+  }
+
+  /**
+   * Set the loader options.
+   *
+   * @param {object} opt The input options.
+   */
+  setOptions(opt) {
+    this.#options = opt;
+  }
+
+  /**
+   * Is the load ongoing?
+   *
+   * @returns {boolean} True if loading.
+   */
+  isLoading() {
+    return this.#isLoading;
+  }
+
+  /**
+   * Set the loading flag.
+   *
+   * @param {boolean} flag The loading flag value.
+   */
+  setLoading(flag) {
+    this.#isLoading = flag;
+  }
+
+  /**
+   * Handle a load start event.
+   * Default does nothing.
+   *
+   * @param {object} _event The load start event.
+   */
+  onloadstart(_event) {}
+
+  /**
+   * Handle a progress event.
+   * Default does nothing.
+   *
+   * @param {object} _event The load progress event.
+   */
+  onprogress(_event) {}
+
+  /**
+   * Handle a load item event.
+   * Default does nothing.
+   *
+   * @param {object} _event The load item event fired
+   *   when a file item has been loaded successfully.
+   */
+  onloaditem(_event) {}
+
+  /**
+   * Handle a load event.
+   * Default does nothing.
+   *
+   * @param {object} _event The load event fired
+   *   when a file has been loaded successfully.
+   */
+  onload(_event) {}
+
+  /**
+   * Handle an load end event.
+   * Default does nothing.
+   *
+   * @param {object} _event The load end event fired
+   *  when a file load has completed, successfully or not.
+   */
+  onloadend(_event) {}
+
+  /**
+   * Handle an error event.
+   * Default does nothing.
+   *
+   * @param {object} _event The error event.
+   */
+  onerror(_event) {}
+
+  /**
+   * Handle an abort event.
+   * Default does nothing.
+   *
+   * @param {object} _event The abort event.
+   */
+  onabort(_event) {}
+
+} // class LoaderBase