BAEL-3091: The Prototype Pattern in Java (changed code based on valid comments from a reader)

spring-boot-client/src/main/java/org/baeldung/boot/Application.java

@@ -0,0 +1,14 @@
+package org.baeldung.boot;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ApplicationContext;
+
+@SpringBootApplication
+public class Application {
+    private static ApplicationContext applicationContext;
+
+    public static void main(String[] args) {
+        applicationContext = SpringApplication.run(Application.class, args);
+    }
+}

spring-boot-client/src/main/java/org/baeldung/boot/client/Details.java

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+package org.baeldung.boot.client;
+
+public class Details {
+
+    private String name;
+
+    private String login;
+
+    public Details() {
+    }
+
+    public Details(String name, String login) {
+        this.name = name;
+        this.login = login;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getLogin() {
+        return login;
+    }
+
+    public void setLogin(String login) {
+        this.login = login;
+    }
+}

spring-boot-client/src/main/java/org/baeldung/boot/client/DetailsServiceClient.java

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+package org.baeldung.boot.client;
+
+import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.stereotype.Service;
+import org.springframework.web.client.RestTemplate;
+
+@Service
+public class DetailsServiceClient {
+
+    private final RestTemplate restTemplate;
+
+    public DetailsServiceClient(RestTemplateBuilder restTemplateBuilder) {
+        restTemplate = restTemplateBuilder.build();
+    }
+
+    public Details getUserDetails(String name) {
+        return restTemplate.getForObject("/{name}/details", Details.class, name);
+    }
+
+}

spring-boot-client/src/main/java/org/baeldung/websocket/client/Message.java

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+package org.baeldung.websocket.client;
+
+public class Message {
+
+    private String from;
+    private String text;
+
+    public String getText() {
+        return text;
+    }
+
+    public String getFrom() {
+        return from;
+    }
+
+    public void setFrom(String from) {
+        this.from = from;
+    }
+
+    public void setText(String text) {
+        this.text = text;
+    }
+
+}

spring-boot-client/src/main/java/org/baeldung/websocket/client/MyStompSessionHandler.java

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+package org.baeldung.websocket.client;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.springframework.messaging.simp.stomp.StompCommand;
+import org.springframework.messaging.simp.stomp.StompHeaders;
+import org.springframework.messaging.simp.stomp.StompSession;
+import org.springframework.messaging.simp.stomp.StompSessionHandlerAdapter;
+
+import java.lang.reflect.Type;
+
+/**
+ * This class is an implementation for <code>StompSessionHandlerAdapter</code>.
+ * Once a connection is established, We subscribe to /topic/messages and 
+ * send a sample message to server.
+ * 
+ * @author Kalyan
+ *
+ */
+public class MyStompSessionHandler extends StompSessionHandlerAdapter {
+
+    private Logger logger = LogManager.getLogger(MyStompSessionHandler.class);
+
+    @Override
+    public void afterConnected(StompSession session, StompHeaders connectedHeaders) {
+        logger.info("New session established : " + session.getSessionId());
+        session.subscribe("/topic/messages", this);
+        logger.info("Subscribed to /topic/messages");
+        session.send("/app/chat", getSampleMessage());
+        logger.info("Message sent to websocket server");
+    }
+
+    @Override
+    public void handleException(StompSession session, StompCommand command, StompHeaders headers, byte[] payload, Throwable exception) {
+        logger.error("Got an exception", exception);
+    }
+
+    @Override
+    public Type getPayloadType(StompHeaders headers) {
+        return Message.class;
+    }
+
+    @Override
+    public void handleFrame(StompHeaders headers, Object payload) {
+        Message msg = (Message) payload;
+        logger.info("Received : " + msg.getText() + " from : " + msg.getFrom());
+    }
+
+    /**
+     * A sample message instance.
+     * @return instance of <code>Message</code>
+     */
+    private Message getSampleMessage() {
+        Message msg = new Message();
+        msg.setFrom("Nicky");
+        msg.setText("Howdy!!");
+        return msg;
+    }
+}

spring-boot-client/src/main/java/org/baeldung/websocket/client/StompClient.java

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+package org.baeldung.websocket.client;
+
+import java.util.Scanner;
+
+import org.springframework.messaging.converter.MappingJackson2MessageConverter;
+import org.springframework.messaging.simp.stomp.StompSessionHandler;
+import org.springframework.web.socket.client.WebSocketClient;
+import org.springframework.web.socket.client.standard.StandardWebSocketClient;
+import org.springframework.web.socket.messaging.WebSocketStompClient;
+
+/**
+ * Stand alone WebSocketStompClient.
+ *
+ */
+public class StompClient {
+
+    private static String URL = "ws://localhost:8080/spring-mvc-java/chat";
+
+    public static void main(String[] args) {
+        WebSocketClient client = new StandardWebSocketClient();
+        WebSocketStompClient stompClient = new WebSocketStompClient(client);
+
+        stompClient.setMessageConverter(new MappingJackson2MessageConverter());
+
+        StompSessionHandler sessionHandler = new MyStompSessionHandler();
+        stompClient.connect(URL, sessionHandler);
+
+        new Scanner(System.in).nextLine(); // Don't close immediately.
+    }
+}

spring-boot-client/src/main/resources/logback.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

spring-boot-client/src/test/java/com/baeldung/websocket/client/MyStompSessionHandlerIntegrationTest.java

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+package com.baeldung.websocket.client;
+
+import org.baeldung.websocket.client.MyStompSessionHandler;
+import org.junit.Test;
+import org.mockito.Mockito;
+import org.springframework.messaging.simp.stomp.StompHeaders;
+import org.springframework.messaging.simp.stomp.StompSession;
+
+public class MyStompSessionHandlerIntegrationTest {
+
+    @Test
+    public void givenValidSession_whenConnected_SendsMessage() {
+        StompSession mockSession = Mockito.mock(StompSession.class);
+        StompHeaders mockHeader = Mockito.mock(StompHeaders.class);
+        MyStompSessionHandler sessionHandler = new MyStompSessionHandler();
+        sessionHandler.afterConnected(mockSession, mockHeader);
+        Mockito.verify(mockSession).subscribe("/topic/messages", sessionHandler);
+        Mockito.verify(mockSession).send(Mockito.anyString(), Mockito.anyObject());
+    }
+}

spring-boot-client/src/test/java/org/baeldung/SpringContextIntegrationTest.java

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+package org.baeldung;
+
+import org.baeldung.boot.Application;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = Application.class)
+public class SpringContextIntegrationTest {
+
+    @Test
+    public void whenSpringContextIsBootstrapped_thenNoExceptions() {
+    }
+}

spring-boot-client/src/test/java/org/baeldung/SpringContextTest.java

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+package org.baeldung;
+
+import org.baeldung.boot.Application;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = Application.class)
+public class SpringContextTest {
+
+    @Test
+    public void whenSpringContextIsBootstrapped_thenNoExceptions() {
+    }
+}

spring-boot-client/src/test/java/org/baeldung/boot/client/DetailsServiceClientIntegrationTest.java

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+package org.baeldung.boot.client;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.test.web.client.match.MockRestRequestMatchers.requestTo;
+import static org.springframework.test.web.client.response.MockRestResponseCreators.withSuccess;
+
+import org.baeldung.boot.Application;
+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.autoconfigure.web.client.RestClientTest;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.client.MockRestServiceServer;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+@RunWith(SpringRunner.class)
+@RestClientTest({ DetailsServiceClient.class, Application.class })
+public class DetailsServiceClientIntegrationTest {
+
+    @Autowired
+    private DetailsServiceClient client;
+
+    @Autowired
+    private MockRestServiceServer server;
+
+    @Autowired
+    private ObjectMapper objectMapper;
+
+    @Before
+    public void setUp() throws Exception {
+        String detailsString = objectMapper.writeValueAsString(new Details("John Smith", "john"));
+        this.server.expect(requestTo("/john/details"))
+            .andRespond(withSuccess(detailsString, MediaType.APPLICATION_JSON));
+    }
+
+    @Test
+    public void whenCallingGetUserDetails_thenClientExecutesCorrectCall() throws Exception {
+
+        Details details = this.client.getUserDetails("john");
+
+        assertThat(details.getLogin()).isEqualTo("john");
+        assertThat(details.getName()).isEqualTo("John Smith");
+
+    }
+
+}