#57 Tomcat server: Add basic embedded tomcat server (#58)

* Tomcat server: Add basic embedded tomcat server

* Added ServletInitializer which scan all Controllers and register them in DispatcherServlet, added corresponding annotations

* add logs and javaDocs to all required files

---------

Co-authored-by: mykola.filimonov <[email protected]>

README.md

@@ -9,7 +9,7 @@ Add Maven dependency to your project:
 <dependency>
     <groupId>io.github.bobocode-breskul</groupId>
     <artifactId>bring</artifactId>
-    <version>1.1</version>
+    <version>1.3</version>
 </dependency>
 ```
 
@@ -18,25 +18,40 @@ The reference [documentation](https://github.com/bobocode-breskul/bring/wiki) in
 
 Here is a quick teaser of a complete Bring application in Java:
 
+Add BringContainer.run("org.example") to your main method, where "org.example" is your package name.
+
 ```java
-import com.breskul.bring.*;
+package org.example;
 
-@RestController
-@BringApplication
-public class Example {
+public class Main {
+  public static void main(String[] args) {
+    BringContainer.run("org.example");
+  }
+}
+```
 
-    @RequestMapping("/")
-    String home() {
-        return "Hello World!";
-    }
+Then create a new Controller with following code
 
-    public static void main(String[] args) {
-        BringApplication.run(Example.class, args);
-    }
+```java
+package org.example;
 
+import io.github.bobocodebreskul.context.annotations.BringComponent;
+import io.github.bobocodebreskul.context.annotations.RestController;
+import io.github.bobocodebreskul.context.annotations.Get;
+
+@RestController("/hello")
+@BringComponent
+public class MyController {
+
+  @Get
+  public String getHello() {
+    return "Hello, world!";
+  }
 }
 ```
 
+Now run the application and open http://localhost:8080/hello in your browser.
+
 ## Features
 
 ### HTTP Server

pom.xml

@@ -67,9 +67,18 @@
     <assertj.version>3.24.2</assertj.version>
     <apache.version>3.13.0</apache.version>
     <mockito.version>5.6.0</mockito.version>
+    <tomcat.version>10.1.16</tomcat.version>
+    <jakarta.version>6.0.0</jakarta.version>
+    <jackson.version>2.16.0</jackson.version>
   </properties>
 
   <dependencies>
+    <dependency>
+      <groupId>jakarta.servlet</groupId>
+      <artifactId>jakarta.servlet-api</artifactId>
+      <version>${jakarta.version}</version>
+      <scope>provided</scope>
+    </dependency>
     <dependency>
       <groupId>ch.qos.logback</groupId>
       <artifactId>logback-classic</artifactId>
@@ -121,6 +130,22 @@
       <artifactId>commons-lang3</artifactId>
       <version>${apache.version}</version>
     </dependency>
+    <dependency>
+      <groupId>org.apache.tomcat.embed</groupId>
+      <artifactId>tomcat-embed-core</artifactId>
+      <version>${tomcat.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.tomcat.embed</groupId>
+      <artifactId>tomcat-embed-jasper</artifactId>
+      <version>${tomcat.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+      <version>${jackson.version}</version>
+    </dependency>
+
 
   </dependencies>
 

src/main/java/io/github/bobocodebreskul/MyController.java

@@ -0,0 +1,15 @@
+package io.github.bobocodebreskul;
+
+import io.github.bobocodebreskul.context.annotations.BringComponent;
+import io.github.bobocodebreskul.context.annotations.RestController;
+import io.github.bobocodebreskul.context.annotations.Get;
+
+@RestController("/hello")
+@BringComponent
+public class MyController {
+
+  @Get
+  public String getHello() {
+    return "Hello, world!";
+  }
+}

src/main/java/io/github/bobocodebreskul/context/annotations/Get.java

@@ -0,0 +1,31 @@
+package io.github.bobocodebreskul.context.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates that the annotated method serves as a GET request handler within a corresponding Controller.
+ * This annotation is intended for use in combination with the {@link RestController @RestController} annotation.
+ *
+ * <p>Usage:</p>
+ * <pre>
+ * {@code
+ * @RestController("/sample")
+ * public class SampleController {
+ *
+ *   @Get
+ *   public YourClass doGet() {
+ *     return new YourClass();
+ *   }
+ * }}
+ * </pre>
+ *
+ * @see RestController
+ */
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Get {
+
+}

src/main/java/io/github/bobocodebreskul/context/annotations/Post.java

@@ -0,0 +1,31 @@
+package io.github.bobocodebreskul.context.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates that the annotated method serves as a POST request handler within a corresponding Controller.
+ * This annotation is designed for use in conjunction with the {@link RestController @RestController} annotation.
+ *
+ * <p>Usage:</p>
+ * <pre>
+ * {@code
+ * @RestController("/sample")
+ * public class SampleController {
+ *
+ *   @Post
+ *   public YourClass doPost() {
+ *     return new YourClass();
+ *   }
+ * }}
+ * </pre>
+ *
+ * @see RestController
+ */
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Post {
+
+}

src/main/java/io/github/bobocodebreskul/context/annotations/RestController.java

@@ -0,0 +1,38 @@
+package io.github.bobocodebreskul.context.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates that the annotated class is a RestController, allowing it to be scanned by the ApplicationContext.
+ * A required request mapping value must be specified. Additionally, HTTP Request Method annotations such as
+ * {@link Get} or {@link Post} should be added to the methods within the controller. The response from these
+ * methods will be automatically converted to JSON and sent as the client's response.
+ *
+ * <p>Usage:</p>
+ * <pre>
+ * {@code
+ * @RestController("/sample")
+ * public class SampleController {
+ *
+ *   @Get
+ *   public YourClass doGet() {
+ *     return new YourClass();
+ *   }
+ * }}
+ * </pre>
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface RestController {
+
+  /**
+   * Represents path to the resource.
+   *
+   * @return the filled controller path
+   */
+  String value();
+}
+

src/main/java/io/github/bobocodebreskul/context/registry/BringContainer.java

@@ -5,19 +5,21 @@
 import io.github.bobocodebreskul.context.exception.FeatureNotImplementedException;
 import io.github.bobocodebreskul.context.exception.InstanceCreationException;
 import io.github.bobocodebreskul.context.exception.NoSuchBeanDefinitionException;
-import io.github.bobocodebreskul.context.exception.NotFoundDeclaredConstructorException;
 import io.github.bobocodebreskul.context.scan.RecursiveClassPathAnnotatedBeanScanner;
 import io.github.bobocodebreskul.context.scan.utils.ScanUtilsImpl;
+import io.github.bobocodebreskul.server.TomcatServer;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import lombok.extern.slf4j.Slf4j;
 
 /**
- * Implementation of the {@link ObjectFactory} as Bring beans container. Creates and holds
- * all found and registered beans.
+ * Implementation of the {@link ObjectFactory} as Bring beans container. Creates and holds all found
+ * and registered beans.
  *
  * @author Ruslan Hladchenko
  * @author Roman Pryshchepa
@@ -36,18 +38,29 @@ public BringContainer(BeanDefinitionRegistry definitionRegistry) {
   }
 
   /**
-   * Collect all bean definitions by specified scan packages and build container to create and hold all found beans.
+   * Collect all bean definitions by specified scan packages and build container to create and hold
+   * all found beans.
    *
    * @param scanPackages packages where to search beans
    * @return created beans container
    */
   public static BringContainer run(String... scanPackages) {
     BeanDefinitionRegistry definitionRegistry = new SimpleBeanDefinitionRegistry();
-    AnnotatedBeanDefinitionReader beanDefinitionReader = new AnnotatedBeanDefinitionReader(definitionRegistry);
-    RecursiveClassPathAnnotatedBeanScanner scanner = new RecursiveClassPathAnnotatedBeanScanner(new ScanUtilsImpl(), beanDefinitionReader);
+    AnnotatedBeanDefinitionReader beanDefinitionReader = new AnnotatedBeanDefinitionReader(
+        definitionRegistry);
+    RecursiveClassPathAnnotatedBeanScanner scanner = new RecursiveClassPathAnnotatedBeanScanner(
+        new ScanUtilsImpl(), beanDefinitionReader);
     scanner.scan(scanPackages);
 
-    return new BringContainer(definitionRegistry);
+    BringContainer container = new BringContainer(definitionRegistry);
+
+    definitionRegistry.getBeanDefinitions()
+        .forEach(beanDefinition -> container.getBean(beanDefinition.getName()));
+
+    ExecutorService executor = Executors.newFixedThreadPool(1);
+    executor.submit(() -> TomcatServer.run(container));
+
+    return container;
   }
 
   // TODO: 1. add dependency injection by @Autowired field
@@ -60,7 +73,9 @@ public Object getBean(String name) {
 
     BeanDefinition beanDefinition = definitionRegistry.getBeanDefinition(name);
     if (beanDefinition == null) {
-      throw new NoSuchBeanDefinitionException("BeanDefinition for bean with name %s is not found! Check configuration and register this bean".formatted(name));
+      throw new NoSuchBeanDefinitionException(
+          "BeanDefinition for bean with name %s is not found! Check configuration and register this bean".formatted(
+              name));
     }
     Class<?> beanClass = beanDefinition.getBeanClass();
     try {
@@ -90,4 +105,8 @@ public Object getBean(String name) {
   public Object getBean(Class<?> clazz) {
     throw new UnsupportedOperationException();
   }
+
+  public List<Object> getAllBeans() {
+    return storageByName.values().stream().toList();
+  }
 }