Added WhenNotNull lib component.

web-view-components/src/main/groovy/groowt/view/component/web/DefaultWebViewComponentScope.groovy

@@ -4,6 +4,7 @@ import groowt.view.component.context.DefaultComponentScope
 import groowt.view.component.web.lib.Each
 import groowt.view.component.web.lib.Echo
 import groowt.view.component.web.lib.IntrinsicHtml
+import groowt.view.component.web.lib.WhenNotNull
 import org.codehaus.groovy.runtime.InvokerHelper
 
 import static WebViewComponentFactories.withAttr
@@ -14,6 +15,7 @@ class DefaultWebViewComponentScope extends DefaultComponentScope implements WebV
         new DefaultWebViewComponentScope().tap {
             addWithAttr(Echo)
             addWithAttr(Each)
+            addWithAttr(WhenNotNull)
         }
     }
 

web-view-components/src/main/groovy/groowt/view/component/web/lib/WhenNotNull.groovy

@@ -0,0 +1,28 @@
+package groowt.view.component.web.lib
+
+import groowt.view.View
+import groowt.view.component.runtime.DefaultComponentWriter
+
+class WhenNotNull extends DelegatingWebViewComponent {
+
+    private final Object item
+    private final Closure render
+
+    WhenNotNull(Map attr) {
+        this.item = attr.item
+        this.render = attr.render
+    }
+
+    @Override
+    protected View getDelegate() {
+        return { Writer w ->
+            if (this.item != null) {
+                def cw = new DefaultComponentWriter(w)
+                cw.renderContext = this.context.renderContext
+                cw.componentContext = this.context
+                cw << this.render(item)
+            }
+        }
+    }
+
+}