feat(demo): add concurrent limit to BigDataset demo

Author: javier-godoy

src/test/java/com/flowingcode/vaadin/addons/gridexporter/GridExporterBigDatasetDemo.java

@@ -19,6 +19,15 @@
  */
 package com.flowingcode.vaadin.addons.gridexporter;
 
+import com.flowingcode.vaadin.addons.demo.DemoSource;
+import com.flowingcode.vaadin.addons.demo.SourceCodeViewer;
+import com.github.javafaker.Faker;
+import com.vaadin.flow.component.Html;
+import com.vaadin.flow.component.grid.Grid;
+import com.vaadin.flow.component.grid.Grid.Column;
+import com.vaadin.flow.component.html.Div;
+import com.vaadin.flow.router.PageTitle;
+import com.vaadin.flow.router.Route;
 import java.io.IOException;
 import java.math.BigDecimal;
 import java.text.SimpleDateFormat;
@@ -27,15 +36,9 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import org.apache.poi.EncryptedDocumentException;
-import com.flowingcode.vaadin.addons.demo.DemoSource;
-import com.github.javafaker.Faker;
-import com.vaadin.flow.component.grid.Grid;
-import com.vaadin.flow.component.grid.Grid.Column;
-import com.vaadin.flow.component.html.Div;
-import com.vaadin.flow.router.PageTitle;
-import com.vaadin.flow.router.Route;
 
 @DemoSource
+@DemoSource("/src/test/java/com/flowingcode/vaadin/addons/gridexporter/VaadinServiceInitListenerImpl.java")
 @PageTitle("Grid Exporter Addon Big Dataset Demo")
 @Route(value = "gridexporter/bigdataset", layout = GridExporterDemoView.class)
 @SuppressWarnings("serial")
@@ -68,14 +71,37 @@ public GridExporterBigDatasetDemo() throws EncryptedDocumentException, IOExcepti
                 }).collect(Collectors.toList());
     grid.setItems(query->persons.stream().skip(query.getOffset()).limit(query.getLimit()));
     grid.setWidthFull();
-    this.setSizeFull();
+    setSizeFull();
     GridExporter<Person> exporter = GridExporter.createFor(grid);
     exporter.setAutoSizeColumns(false);
     exporter.setExportValue(budgetCol, item -> "" + item.getBudget());
     exporter.setColumnPosition(lastNameCol, 1);
     exporter.setTitle("People information");
     exporter.setFileName(
         "GridExport" + new SimpleDateFormat("yyyyddMM").format(Calendar.getInstance().getTime()));
+
+    // begin-block concurrent
+    // #if vaadin eq 0
+    Html concurrent = new Html(
+        """
+            <div>
+            This configuration prepares the exporter for the BigDataset demo, enabling it to manage resource-intensive
+            document generation tasks effectively. In this setup, an upper limit of 10 is established for the cost of
+            concurrent downloads, and the big dataset exporter is configured with a cost of 9, while other exporters
+            handling smaller datasets retain the default cost of 1. This customization allows a combination of one large
+            dataset download alongside one small dataset download, or up to 10 concurrent downloads of smaller datasets
+            when no big dataset is being exported.<p>
+
+            Additionally, <code>setConcurrentDownloadTimeout</code> enforces a timeout for acquiring the necessary permits
+            during a download operation. If the permits are not obtained within the specified timeframe, the download
+            request will be aborted, preventing prolonged waiting periods, especially during peak system loads.
+            </div>""");
+    add(concurrent);
+    // #endif
+    SourceCodeViewer.highlightOnHover(concurrent, "concurrent");
+    exporter.setConcurrentDownloadCost(9);
+    // end-block
+
     add(grid);
   }
 }

src/test/java/com/flowingcode/vaadin/addons/gridexporter/VaadinServiceInitListenerImpl.java

@@ -0,0 +1,15 @@
+package com.flowingcode.vaadin.addons.gridexporter;
+
+import com.vaadin.flow.server.ServiceInitEvent;
+import com.vaadin.flow.server.VaadinServiceInitListener;
+import java.util.concurrent.TimeUnit;
+
+public class VaadinServiceInitListenerImpl implements VaadinServiceInitListener {
+
+  @Override
+  public void serviceInit(ServiceInitEvent event) {
+    GridExporter.setConcurrentDownloadLimit(10);
+    GridExporter.setConcurrentDownloadTimeout(5, TimeUnit.SECONDS);
+  }
+
+}

src/test/resources/META-INF/services/com.vaadin.flow.server.VaadinServiceInitListener

@@ -0,0 +1 @@
+com.flowingcode.vaadin.addons.gridexporter.VaadinServiceInitListenerImpl