Bael 1273 Spring RSS Feed View (#4707)

* Added example for BAEL-1273 - rss feed with Spring.

* Fixed javadoc

* Removed useless SpringBootServletInitializer in RSS app's launcher

* Explicitely added Spring Boot starting class in pom.xml to prevent errors in package phase.

spring-mvc-java/pom.xml

@@ -141,6 +141,13 @@
             <groupId>com.google.code.gson</groupId>
             <artifactId>gson</artifactId>
         </dependency>
+        
+        <!-- ROME for RSS -->
+		<dependency>
+			<groupId>com.rometools</groupId>
+			<artifactId>rome</artifactId>
+			<version>${rome.version}</version>
+		</dependency>
     </dependencies>
 
     <build>
@@ -283,7 +290,13 @@
         <!-- excel -->
         <poi.version>3.16-beta1</poi.version>
 
+        <!-- ROME for RSS -->
+        <rome.version>1.10.0</rome.version>
+
         <javax.el.version>2.2.4</javax.el.version>
+		
+		<!-- Initial application class for Spring Boot -->        
+        <start-class>com.baeldung.app.Application</start-class>
     </properties>
 
 </project>

spring-mvc-java/src/main/java/com/baeldung/rss/RssFeedApplication.java

@@ -0,0 +1,23 @@
+package com.baeldung.rss;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Spring Boot launcher for an application which exposes an RSS Feed.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+@SpringBootApplication
+public class RssFeedApplication {
+
+	/**
+	 * Launches a Spring Boot application which exposes an RSS Feed.
+	 * 
+	 * @param args null
+	 */
+    public static void main(final String[] args) {
+        SpringApplication.run(RssFeedApplication.class, args);
+    }
+}

spring-mvc-java/src/main/java/com/baeldung/rss/RssFeedController.java

@@ -0,0 +1,32 @@
+package com.baeldung.rss;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.servlet.View;
+
+/**
+ * REST Controller which returns an RSS Feed created by {@link RssFeedView}.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+@RestController
+public class RssFeedController {
+
+	/**
+	 * View used by this controller.
+	 */
+	@Autowired
+	private RssFeedView view;
+
+	/**
+	 * Returns an RSS Feed created by {@link #view}.
+	 * 
+	 * @return an RSS Feed
+	 */
+	@GetMapping("/rss")
+	public View getFeed() {
+		return view;
+	}
+}

spring-mvc-java/src/main/java/com/baeldung/rss/RssFeedView.java

@@ -0,0 +1,98 @@
+package com.baeldung.rss;
+
+import java.sql.Date;
+import java.time.Instant;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.view.feed.AbstractRssFeedView;
+
+import com.rometools.rome.feed.rss.Channel;
+import com.rometools.rome.feed.rss.Item;
+
+/**
+ * View for a RSS feed.
+ * 
+ * @author Donato Rimenti
+ */
+@Component
+public class RssFeedView extends AbstractRssFeedView {
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see org.springframework.web.servlet.view.feed.AbstractFeedView#
+	 * buildFeedMetadata(java.util.Map, com.rometools.rome.feed.WireFeed,
+	 * javax.servlet.http.HttpServletRequest)
+	 */
+	@Override
+	protected void buildFeedMetadata(Map<String, Object> model, Channel feed, HttpServletRequest request) {
+		feed.setTitle("Baeldung RSS Feed");
+		feed.setDescription("Learn how to program in Java");
+		feed.setLink("http://www.baeldung.com");
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see org.springframework.web.servlet.view.feed.AbstractRssFeedView#
+	 * buildFeedItems(java.util.Map, javax.servlet.http.HttpServletRequest,
+	 * javax.servlet.http.HttpServletResponse)
+	 */
+	@Override
+	protected List<Item> buildFeedItems(Map<String, Object> model, HttpServletRequest request,
+			HttpServletResponse response) {
+
+		// Builds the single entries.
+		Item entryOne = new Item();
+		entryOne.setTitle("JUnit 5 @Test Annotation");
+		entryOne.setAuthor("donatohan.rimenti@gmail.com");
+		entryOne.setLink("http://www.baeldung.com/junit-5-test-annotation");
+		entryOne.setPubDate(Date.from(Instant.parse("2017-12-19T00:00:00Z")));
+
+		Item entryTwo = new Item();
+		entryTwo.setTitle("Creating and Configuring Jetty 9 Server in Java");
+		entryTwo.setAuthor("donatohan.rimenti@gmail.com");
+		entryTwo.setLink("http://www.baeldung.com/jetty-java-programmatic");
+		entryTwo.setPubDate(Date.from(Instant.parse("2018-01-23T00:00:00Z")));
+
+		Item entryThree = new Item();
+		entryThree.setTitle("Flyweight Pattern in Java");
+		entryThree.setAuthor("donatohan.rimenti@gmail.com");
+		entryThree.setLink("http://www.baeldung.com/java-flyweight");
+		entryThree.setPubDate(Date.from(Instant.parse("2018-02-01T00:00:00Z")));
+
+		Item entryFour = new Item();
+		entryFour.setTitle("Multi-Swarm Optimization Algorithm in Java");
+		entryFour.setAuthor("donatohan.rimenti@gmail.com");
+		entryFour.setLink("http://www.baeldung.com/java-multi-swarm-algorithm");
+		entryFour.setPubDate(Date.from(Instant.parse("2018-03-09T00:00:00Z")));
+
+		Item entryFive = new Item();
+		entryFive.setTitle("A Simple Tagging Implementation with MongoDB");
+		entryFive.setAuthor("donatohan.rimenti@gmail.com");
+		entryFive.setLink("http://www.baeldung.com/mongodb-tagging");
+		entryFive.setPubDate(Date.from(Instant.parse("2018-03-27T00:00:00Z")));
+
+		Item entrySix = new Item();
+		entrySix.setTitle("Double-Checked Locking with Singleton");
+		entrySix.setAuthor("donatohan.rimenti@gmail.com");
+		entrySix.setLink("http://www.baeldung.com/java-singleton-double-checked-locking");
+		entrySix.setPubDate(Date.from(Instant.parse("2018-04-23T00:00:00Z")));
+
+		Item entrySeven = new Item();
+		entrySeven.setTitle("Introduction to Dagger 2");
+		entrySeven.setAuthor("donatohan.rimenti@gmail.com");
+		entrySeven.setLink("http://www.baeldung.com/dagger-2");
+		entrySeven.setPubDate(Date.from(Instant.parse("2018-06-30T00:00:00Z")));
+
+		// Creates the feed.
+		return Arrays.asList(entryOne, entryTwo, entryThree, entryFour, entryFive, entrySix, entrySeven);
+	}
+
+}

spring-mvc-java/src/test/java/com/baeldung/rss/RssFeedUnitTest.java

@@ -0,0 +1,62 @@
+package com.baeldung.rss;
+
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import org.springframework.web.context.WebApplicationContext;
+
+/**
+ * Test for {@link RssFeedApplication}.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringBootTest(classes = RssFeedApplication.class)
+public class RssFeedUnitTest {
+
+	/**
+	 * Application context.
+	 */
+	@Autowired
+	private WebApplicationContext context;
+
+	/**
+	 * Mock to perform tests on Spring Web Controller.
+	 */
+	private MockMvc mvc;
+
+	/**
+	 * Sets the test up.
+	 */
+	@Before
+	public void setup() {
+		mvc = MockMvcBuilders.webAppContextSetup(context).build();
+	}
+
+	/**
+	 * Calls the RSS feed endpoint and checks that the result matches an
+	 * expected one.
+	 * 
+	 * @throws Exception
+	 */
+	@Test
+	public void givenRssFeed_whenComparedWithExisting_thenEquals() throws Exception {
+		// The expected response.
+		String expectedResult = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><rss version=\"2.0\"> <channel> <title>Baeldung RSS Feed</title> <link>http://www.baeldung.com</link> <description>Learn how to program in Java</description> <item> <title>JUnit 5 @Test Annotation</title> <link>http://www.baeldung.com/junit-5-test-annotation</link> <pubDate>Tue, 19 Dec 2017 00:00:00 GMT</pubDate> <author>donatohan.rimenti@gmail.com</author> </item> <item> <title>Creating and Configuring Jetty 9 Server in Java</title> <link>http://www.baeldung.com/jetty-java-programmatic</link> <pubDate>Tue, 23 Jan 2018 00:00:00 GMT</pubDate> <author>donatohan.rimenti@gmail.com</author> </item> <item> <title>Flyweight Pattern in Java</title> <link>http://www.baeldung.com/java-flyweight</link> <pubDate>Thu, 01 Feb 2018 00:00:00 GMT</pubDate> <author>donatohan.rimenti@gmail.com</author> </item> <item> <title>Multi-Swarm Optimization Algorithm in Java</title> <link>http://www.baeldung.com/java-multi-swarm-algorithm</link> <pubDate>Fri, 09 Mar 2018 00:00:00 GMT</pubDate> <author>donatohan.rimenti@gmail.com</author> </item> <item> <title>A Simple Tagging Implementation with MongoDB</title> <link>http://www.baeldung.com/mongodb-tagging</link> <pubDate>Tue, 27 Mar 2018 00:00:00 GMT</pubDate> <author>donatohan.rimenti@gmail.com</author> </item> <item> <title>Double-Checked Locking with Singleton</title> <link>http://www.baeldung.com/java-singleton-double-checked-locking</link> <pubDate>Mon, 23 Apr 2018 00:00:00 GMT</pubDate> <author>donatohan.rimenti@gmail.com</author> </item> <item> <title>Introduction to Dagger 2</title> <link>http://www.baeldung.com/dagger-2</link> <pubDate>Sat, 30 Jun 2018 00:00:00 GMT</pubDate> <author>donatohan.rimenti@gmail.com</author> </item> </channel></rss>";
+
+		// Performs a post against the RSS feed endpoint and checks that the
+		// result is equals to the expected one.
+		mvc.perform(MockMvcRequestBuilders.get("/rss")).andExpect(status().isOk())
+				.andExpect(content().xml(expectedResult));
+	}
+
+}