feat: add annotation-based configuration

Author: javier-godoy

src/main/java/com/flowingcode/vaadin/addons/demo/DemoSource.java

@@ -0,0 +1,18 @@
+package com.flowingcode.vaadin.addons.demo;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * This annotation is used for configuring the source code URL in a {@link TabbedDemo}
+ *
+ * @author Javier Godoy / Flowing Code
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+public @interface DemoSource {
+
+  String value();
+}

src/main/java/com/flowingcode/vaadin/addons/demo/TabbedDemo.java

@@ -27,8 +27,10 @@
 import com.vaadin.flow.component.splitlayout.SplitLayout.Orientation;
 import com.vaadin.flow.component.tabs.Tab;
 import com.vaadin.flow.component.tabs.Tabs;
+import com.vaadin.flow.router.PageTitle;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Optional;
 
 @StyleSheet("context://frontend/styles/commons-demo/shared-styles.css")
 @SuppressWarnings("serial")
@@ -84,6 +86,26 @@ public TabbedDemo() {
     setSizeFull();
   }
 
+  /**
+   * Add a tab with a {@code demo} component. The tab label and source code URL are retrieved from
+   * the {@link PageTitle} (required) and {@link DemoSource} (optional) annotations in the demo
+   * class, respectively.
+   *
+   * @param demo the demo instance
+   */
+  public void addDemo(Component demo) {
+    String sourceCodeUrl =
+        Optional.ofNullable(demo.getClass().getAnnotation(DemoSource.class))
+            .map(DemoSource::value)
+            .orElse(null);
+    String label =
+        Optional.ofNullable(demo.getClass().getAnnotation(PageTitle.class))
+            .map(PageTitle::value)
+            .orElse(demo.getClass().getName());
+
+    addDemo(demo, label, sourceCodeUrl);
+  }
+
   /**
    * @param demo the demo instance
    * @param name the demo name (tab label)

src/test/java/com/flowingcode/vaadin/addons/demo/Demo.java

@@ -47,6 +47,8 @@ public Demo() {
     vl3.add(tf);
     tabbedDemo.addDemo(vl3, "Demo Without Source Code");
 
+    tabbedDemo.addDemo(new SampleDemo());
+
     add(tabbedDemo);
     setSizeFull();
   }

src/test/java/com/flowingcode/vaadin/addons/demo/SampleDemo.java

@@ -0,0 +1,15 @@
+package com.flowingcode.vaadin.addons.demo;
+
+import com.vaadin.flow.component.html.Div;
+import com.vaadin.flow.component.html.Span;
+import com.vaadin.flow.router.PageTitle;
+
+@PageTitle("Demo 4")
+@DemoSource(
+    "https://github.com/FlowingCode/CommonsDemo/blob/master/src/test/java/com/flowingcode/vaadin/addons/demo/impl/SampleDemo.java")
+public class SampleDemo extends Div {
+
+  public SampleDemo() {
+    add(new Span("Demo component with annotations"));
+  }
+}