feat: add new constructor using DownloadHandler

Author: paodb

vcf-pdf-viewer-demo/src/main/java/com/vaadin/componentfactory/pdfviewer/BasicPdfViewerExample.java

@@ -2,7 +2,7 @@
 
 import com.vaadin.flow.component.html.Div;
 import com.vaadin.flow.router.Route;
-import com.vaadin.flow.server.StreamResource;
+import com.vaadin.flow.server.streams.DownloadHandler;
 
 @Route(value = "", layout = MainLayout.class)
 public class BasicPdfViewerExample extends Div {
@@ -11,8 +11,7 @@ public BasicPdfViewerExample() {
 
     PdfViewer pdfViewer = new PdfViewer();
     pdfViewer.setSizeFull();
-    StreamResource resource = new StreamResource("example.pdf", () -> getClass().getResourceAsStream("/pdf/example.pdf"));
-    pdfViewer.setSrc(resource);
+    pdfViewer.setSrc(DownloadHandler.forClassResource(getClass(), "/pdf/example.pdf", "example.pdf"));
     add(pdfViewer);    
   }
 

vcf-pdf-viewer/src/main/java/com/vaadin/componentfactory/pdfviewer/PdfViewer.java

@@ -35,6 +35,7 @@
 import com.vaadin.flow.component.icon.Icon;
 import com.vaadin.flow.component.icon.VaadinIcon;
 import com.vaadin.flow.server.AbstractStreamResource;
+import com.vaadin.flow.server.streams.DownloadHandler;
 import org.apache.commons.lang3.StringUtils;
 
 @Tag("vcf-pdf-viewer")
@@ -101,6 +102,18 @@ public void setSrc(AbstractStreamResource src) {
     updateDownloadSource();
   }
 
+  /**
+   * Sets a pdf file to render as a DownloadHandler.
+   * <p>
+   * Example: {@code DownloadHandler.forClassResource(getClass(), "mypdf.pdf")} 
+   * 
+   * @since 5.0.0
+   */
+  public void setSrc(DownloadHandler downloadHandler) {
+    getElement().setAttribute("src", downloadHandler);
+    updateDownloadSource();
+  }
+  
   /**
    * @return current zoom level
    */