Changed configuration to enable XML based responses

Having content negotiation with more than just JSON content
might follow REST principles.

All entities annotated with e.g. @XmlRootElement can be send as XML data.
This requires client to send Accept header with value "application/json"
to fetch JSON responses.
Default Accept header send by client is something like:
"text/html,application/xhtml+xml,application/xml"
which requests an XML document, not JSON document but JSON is expected.

src/main/java/de/thm/arsnova/entities/Statistics.java

@@ -11,50 +11,50 @@ public class Statistics {
 	public int getAnswers() {
 		return answers;
 	}
-	public void setAnswers(int answers) {
+	public void setAnswers(final int answers) {
 		this.answers = answers;
 	}
 
 	public int getQuestions() {
 		return questions;
 	}
-	public void setQuestions(int questions) {
+	public void setQuestions(final int questions) {
 		this.questions = questions;
 	}
 
 	public int getOpenSessions() {
 		return openSessions;
 	}
-	public void setOpenSessions(int openSessions) {
+	public void setOpenSessions(final int openSessions) {
 		this.openSessions = openSessions;
 	}
 
 	public int getClosedSessions() {
 		return closedSessions;
 	}
-	public void setClosedSessions(int closedSessions) {
+	public void setClosedSessions(final int closedSessions) {
 		this.closedSessions = closedSessions;
 	}
 
 	public int getActiveUsers() {
 		return activeUsers;
 	}
-	public void setActiveUsers(int activeUsers) {
+	public void setActiveUsers(final int activeUsers) {
 		this.activeUsers = activeUsers;
 	}
 
 	@Override
 	public int hashCode() {
 		return (this.getClass().getName()
-				+ this.activeUsers
-				+ this.answers
-				+ this.closedSessions
-				+ this.openSessions
-				+ this.questions).hashCode();
+				+ activeUsers
+				+ answers
+				+ closedSessions
+				+ openSessions
+				+ questions).hashCode();
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(final Object obj) {
 		if (obj == null) {
 			return false;
 		}
@@ -62,8 +62,8 @@ public class Statistics {
 			return true;
 		}
 		if (obj instanceof Statistics) {
-			Statistics other = (Statistics) obj;
-			return this.hashCode() == other.hashCode();
+			final Statistics other = (Statistics) obj;
+			return hashCode() == other.hashCode();
 		}
 
 		return false;

src/main/webapp/WEB-INF/spring/arsnova-servlet.xml

@@ -22,10 +22,12 @@
 		class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
 		<property name="favorPathExtension" value="false" />
 		<property name="favorParameter" value="true" />
+		<property name="defaultContentType" value="application/json" />
 		<property name="mediaTypes">
 			<value>
 				html=text/html
 				json=application/json
+				xml=application/xml
 			</value>
 		</property>
 	</bean>

src/test/java/de/thm/arsnova/controller/StatisticsControllerTest.java

@@ -10,6 +10,7 @@ import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.MediaType;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.test.context.web.WebAppConfiguration;
@@ -43,35 +44,35 @@ public class StatisticsControllerTest {
 
 	@Test
 	public final void testShouldGetCurrentOnlineUsers() throws Exception {
-		mockMvc.perform(get("/statistics/activeusercount"))
+		mockMvc.perform(get("/statistics/activeusercount").accept(MediaType.TEXT_PLAIN))
 		.andExpect(status().isOk())
 		.andExpect(content().string("0"));
 	}
 
 	@Test
 	public final void testShouldSendXDeprecatedApiForGetCurrentOnlineUsers() throws Exception {
-		mockMvc.perform(get("/statistics/activeusercount"))
+		mockMvc.perform(get("/statistics/activeusercount").accept(MediaType.TEXT_PLAIN))
 		.andExpect(status().isOk())
 		.andExpect(header().string(AbstractController.X_DEPRECATED_API,"1"));
 	}
 
 	@Test
 	public final void testShouldGetSessionCount() throws Exception {
-		mockMvc.perform(get("/statistics/sessioncount"))
+		mockMvc.perform(get("/statistics/sessioncount").accept(MediaType.TEXT_PLAIN))
 		.andExpect(status().isOk())
 		.andExpect(content().string("3"));
 	}
 
 	@Test
 	public final void testShouldSendXDeprecatedApiForGetSessionCount() throws Exception {
-		mockMvc.perform(get("/statistics/sessioncount"))
+		mockMvc.perform(get("/statistics/sessioncount").accept(MediaType.TEXT_PLAIN))
 		.andExpect(status().isOk())
 		.andExpect(header().string(AbstractController.X_DEPRECATED_API,"1"));
 	}
 
 	@Test
 	public final void testShouldGetStatistics() throws Exception {
-		mockMvc.perform(get("/statistics"))
+		mockMvc.perform(get("/statistics").accept(MediaType.APPLICATION_JSON))
 		.andExpect(status().isOk())
 		.andExpect(jsonPath("$.answers").value(0))
 		.andExpect(jsonPath("$.questions").value(0))
@@ -82,7 +83,7 @@ public class StatisticsControllerTest {
 
 	@Test
 	public final void testShouldGetCacheControlHeaderForStatistics() throws Exception {
-		mockMvc.perform(get("/statistics"))
+		mockMvc.perform(get("/statistics").accept(MediaType.APPLICATION_JSON))
 		.andExpect(status().isOk())
 		.andExpect(header().string("cache-control", "public, max-age=60"));
 	}