Added Rest UI Example

pom.xml

@@ -73,6 +73,11 @@
 			<artifactId>javafaker</artifactId>
 			<version>1.0.2</version>
 		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.core</groupId>
+			<artifactId>jackson-databind</artifactId>
+			<version>2.10.0</version>
+		</dependency>
 	</dependencies>
 
 	<build>

src/main/java/dev/dhbw/testproject/vaadintest/CatFact.java

@@ -0,0 +1,17 @@
+package dev.dhbw.testproject.vaadintest;
+
+public class CatFact
+{
+    private String factString;
+
+    public CatFact(String fact)
+    {
+        this.factString = fact;
+    }
+
+    public String getFactString()
+    {
+        return factString;
+    }
+
+}

src/main/java/dev/dhbw/testproject/vaadintest/CatFactModel.java

@@ -0,0 +1,24 @@
+package dev.dhbw.testproject.vaadintest;
+
+import java.util.List;
+
+public class CatFactModel
+{
+
+    private List<String> data;
+
+    public CatFactModel()
+    {
+    }
+
+    public List<String> getData()
+    {
+        return data;
+    }
+
+    public void setData(List<String> data)
+    {
+        this.data = data;
+    }
+
+}

src/main/java/dev/dhbw/testproject/vaadintest/MainUI.java

@@ -16,6 +16,7 @@ import com.vaadin.data.provider.ListDataProvider;
 import com.vaadin.server.Page;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.server.VaadinServlet;
+import com.vaadin.server.LegacyCommunicationManager.ClientCache;
 import com.vaadin.ui.Button;
 import com.vaadin.ui.Button.ClickEvent;
 import com.vaadin.ui.Button.ClickListener;
@@ -81,6 +82,7 @@ public class MainUI extends UI
             }
         });
 
+
         personAdditionLayout.addComponents(nameField, surnameField, dateField, formCompleteButton);
         
         layout.addComponents(grid, personAdditionLayout);

src/main/java/dev/dhbw/testproject/vaadintest/RestUI.java

@@ -0,0 +1,140 @@
+package dev.dhbw.testproject.vaadintest;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+import javax.servlet.annotation.WebServlet;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.vaadin.annotations.Theme;
+import com.vaadin.annotations.VaadinServletConfiguration;
+import com.vaadin.server.Page;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.server.VaadinServlet;
+import com.vaadin.shared.ui.ContentMode;
+import com.vaadin.ui.Button;
+import com.vaadin.ui.Label;
+import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
+import com.vaadin.ui.Button.ClickEvent;
+import com.vaadin.ui.Button.ClickListener;
+
+
+@Theme("mytheme")
+public class RestUI extends UI
+{
+
+    private static final long serialVersionUID = 2824052883319408801L;
+
+    private final static ObjectMapper MAPPER = new ObjectMapper();
+
+    @Override
+    protected void init(VaadinRequest request)
+    {
+        VerticalLayout factLayout = new VerticalLayout();
+        factLayout.setId("factLayout");
+        
+        CatFact initialCatFact = getCatFactFromService();
+        
+        Label siteHeader = new Label("<h1>Get your dose of cat facts</h1>", ContentMode.HTML);
+        
+        Label catFactLabel = new Label("<p>" + initialCatFact.getFactString() + "</p>", ContentMode.HTML);
+        catFactLabel.setId("factLabel");
+               
+        Button factRefreshButton = new Button("Get new cat fact.");
+        
+        Page.getCurrent().getStyles().add("#factLayout{padding: 30px 20%;} #factLabel{padding-bottom: 20px;}");
+        factRefreshButton.addClickListener(new ClickListener()
+        {
+            private static final long serialVersionUID = -6384557494236864977L;
+
+            @Override
+            public void buttonClick(ClickEvent event)
+            {
+                CatFact randomCatFact = getCatFactFromService();
+                catFactLabel.setValue("<p>" + randomCatFact.getFactString() + "</p>");
+            }
+        });
+        
+        factLayout.addComponents(siteHeader, catFactLabel, factRefreshButton);
+
+        setContent(factLayout);
+    }
+
+    private CatFact getCatFactFromService()
+    {
+        String jsonOutput = getResponseFromService();
+
+        CatFactModel model = parseCatModel(jsonOutput);
+
+        CatFact output = convertToInternalModel(model);
+
+        return output;
+    }
+
+    private String getResponseFromService()
+    {
+        String response = "";
+        try
+        {
+
+            URL url = new URL("https://meowfacts.herokuapp.com");
+            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+            conn.setRequestMethod("GET");
+            conn.setRequestProperty("Accept", "application/json");
+            if (conn.getResponseCode() != 200)
+            {
+                throw new RuntimeException("Failed : HTTP Error code : " + conn.getResponseCode());
+            }
+            InputStreamReader in = new InputStreamReader(conn.getInputStream());
+            BufferedReader br = new BufferedReader(in);
+
+            response = br.readLine();
+
+            conn.disconnect();
+
+        }
+        catch (Exception e)
+        {
+            System.out.println("Exception in NetClientGet:- " + e);
+        }
+
+        return response;
+    }
+
+    private CatFactModel parseCatModel(String jsonString)
+    {
+        CatFactModel model = null;
+
+        try
+        {
+            model = MAPPER.readValue(jsonString, CatFactModel.class);
+        }
+        catch (JsonProcessingException e)
+        {
+            e.printStackTrace();
+        }
+
+        return model;
+    }
+
+    private CatFact convertToInternalModel(CatFactModel model)
+    {
+        return new CatFact(model.getData().get(0));
+    }
+
+    /**
+     * This is a basic Servlet which configures the URL where this page is available
+     * and actually deploys it to there.
+     */
+    @WebServlet("/rest/*")
+    @VaadinServletConfiguration(ui = RestUI.class, productionMode = false)
+    public static class RestServlet extends VaadinServlet
+    {
+        private static final long serialVersionUID = -294459246930641751L;
+
+    }
+}