SCT-4 Added SimpleTaskConfiguration

* Added unit tests
* Introduced @EnableTask
* Readme updated to include @EnableTask
* Removed warnings from build
* Cleanup

spring-cloud-task-core/src/main/java/org/springframework/cloud/task/annotation/EnableTask.java

@@ -0,0 +1,68 @@
+
+/*
+ * Copyright 2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.task.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.cloud.task.configuration.DefaultTaskConfigurer;
+import org.springframework.cloud.task.configuration.SimpleTaskConfiguration;
+import org.springframework.cloud.task.configuration.TaskConfigurer;
+import org.springframework.cloud.task.repository.TaskRepository;
+import org.springframework.context.annotation.Import;
+
+/**
+ * <p>
+ * Enable Spring Task features and provide a base configuration for setting up
+ * {@link Task} objects in an &#064;Configuration class.
+ *
+ * <pre class="code">
+ * &#064;Configuration
+ * &#064;EnableTask
+ * public class AppConfig {
+ *
+ * 	&#064;Bean
+ * 	public MyCommandLineRunner myCommandLineRunner() {
+ * 		return new MyCommandLineRunner()
+ * 	}
+ * }
+ * </pre>
+ *
+ * Note that only one of your configuration classes needs to have the <code>&#064;EnableTask</code>
+ * annotation. Once you have an <code>&#064;EnableTask</code> class in your configuration
+ * you will have an instance of {@link TaskConfigurer}.  If one is not specified then the
+ * {@link DefaultTaskConfigurer} will be used.
+ * You will also be able to <code>&#064;Autowired</code> some useful stuff into your context:
+ *
+ * <ul>
+ * <li>a {@link TaskRepository} (bean name "taskRepository").</li>
+ * </ul>
+ *
+ * @author Glenn Renfro
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Inherited
+@Import(SimpleTaskConfiguration.class)
+public @interface EnableTask {
+}

spring-cloud-task-core/src/main/java/org/springframework/cloud/task/annotation/Task.java

@@ -23,10 +23,6 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.springframework.cloud.task.configuration.DefaultTaskConfigurer;
-import org.springframework.context.annotation.Import;
-import org.springframework.stereotype.Component;
-
 /**
  * Annotation that identifies a class as a task.   This annotation will serve as the
  * main “hook” to activate the various Spring Cloud Task features.
@@ -37,12 +33,11 @@ import org.springframework.stereotype.Component;
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Inherited
-@Component
-@Import({ DefaultTaskConfigurer.class })
 public @interface Task {
 
 	/**
 	 * Establishes the name associated with the task.  The default is empty.
+	 * @return returns name associated with the task or an empty string.
 	 */
 	public String value() default "";
 

spring-cloud-task-core/src/main/java/org/springframework/cloud/task/configuration/DefaultTaskConfigurer.java

@@ -16,28 +16,26 @@
 
 package org.springframework.cloud.task.configuration;
 
-import org.springframework.cloud.task.repository.support.LoggerTaskRepository;
 import org.springframework.cloud.task.repository.TaskRepository;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.context.annotation.Scope;
+import org.springframework.cloud.task.repository.support.LoggerTaskRepository;
 
 /**
- * If no TaskConfigurer is present this configuration will be used.
+ * If no {@link TaskConfigurer} is present, then this configuration will be used.
+ * The following defaults will be used:
+ *
+ * <ul>
+ * <li>{@link LoggerTaskRepository} will be the default {@link TaskRepository}.</li>
+ * </ul>
+ *
+ *
  * @author Glenn Renfro
  */
-@Configuration
-public class DefaultTaskConfigurer {
+public class DefaultTaskConfigurer implements TaskConfigurer{
 
-	@Bean
-	@Scope("prototype")
-	public TaskHandler taskHandler() {
-		return new TaskHandler();
+	public DefaultTaskConfigurer(){
 	}
 
-
-	@Bean
-	public TaskRepository taskRepository() {
+	public TaskRepository getTaskRepository() {
 		return new LoggerTaskRepository();
 	}
 

spring-cloud-task-core/src/main/java/org/springframework/cloud/task/configuration/SimpleTaskConfiguration.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.task.configuration;
+
+import java.util.Collection;
+
+import javax.annotation.PostConstruct;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.cloud.task.repository.TaskRepository;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Scope;
+
+/**
+ * Base {@code Configuration} class providing common structure for enabling and using
+ * Spring Task. Customization is
+ * available by implementing the {@link TaskConfigurer} interface.
+ *
+ * @author Glenn Renfro
+ */
+@Configuration
+public class SimpleTaskConfiguration {
+
+	@Autowired
+	private ApplicationContext context;
+
+	private boolean initialized = false;
+
+	private TaskRepository taskRepository;
+
+	private TaskConfigurer configurer;
+
+	@Bean
+	@Scope("prototype")
+	public TaskHandler taskHandler() {
+		return new TaskHandler();
+	}
+
+	@Bean
+	public TaskRepository taskRepository(){
+		return taskRepository;
+	}
+	
+	/**
+	 * Sets up the basic components by extracting them from the {@link TaskConfigurer}, defaulting to some
+	 * sensible values as long as a unique DataSource is available.
+	 */
+	@PostConstruct
+	private void initialize()  {
+		if (initialized) {
+			return;
+		}
+		TaskConfigurer configurer = getConfigurer(context.getBeansOfType(TaskConfigurer.class).values());
+		taskRepository = configurer.getTaskRepository();
+		initialized = true;
+	}
+
+	private TaskConfigurer getConfigurer(Collection<TaskConfigurer> configurers) {
+		if (this.configurer != null) {
+			return this.configurer;
+		}
+		if (configurers == null || configurers.isEmpty()) {
+			DefaultTaskConfigurer configurer = new DefaultTaskConfigurer();
+			this.configurer = configurer;
+			return configurer;
+		}
+		if (configurers.size() > 1) {
+			throw new IllegalStateException(
+					"To use a custom TaskConfigurer the context must contain precisely one, found "
+							+ configurers.size());
+		}
+		this.configurer = configurers.iterator().next();
+		return this.configurer;
+	}
+}

spring-cloud-task-core/src/main/java/org/springframework/cloud/task/configuration/TaskConfigurer.java

@@ -31,6 +31,6 @@ public interface TaskConfigurer {
 	 *
 	 * @return A TaskRepository
 	 */
-	public TaskRepository taskRepository();
+	public TaskRepository getTaskRepository();
 
 }

spring-cloud-task-core/src/main/java/org/springframework/cloud/task/configuration/TaskHandler.java

@@ -26,6 +26,8 @@ import org.aspectj.lang.annotation.AfterThrowing;
 import org.aspectj.lang.annotation.Aspect;
 import org.aspectj.lang.annotation.Before;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.ApplicationRunner;
+import org.springframework.boot.CommandLineRunner;
 import org.springframework.boot.ExitCodeGenerator;
 import org.springframework.cloud.task.annotation.Task;
 import org.springframework.cloud.task.repository.TaskExecution;
@@ -33,8 +35,9 @@ import org.springframework.cloud.task.repository.TaskRepository;
 import org.springframework.context.ApplicationContext;
 
 /**
- * Offers the advice on how to record tasks to the repository for both applicationrunner
- * and commandlinerunner spring boot applications.
+ * Offers the advice on how to record tasks to the repository for both
+ * {@link org.springframework.boot.ApplicationRunner} and
+ * {@link org.springframework.boot.CommandLineRunner} spring boot applications.
  *
  * @author Glenn Renfro
  */
@@ -54,11 +57,12 @@ public class TaskHandler {
 	private TaskExecution taskExecution;
 
 	/**
-	 * Looks for any CommandLineRunner.run method with its class annotated with @Task
+	 * Looks for any {@link CommandLineRunner}.run method with its class annotated with @Task
 	 * and calls the repository implementation to store the start of the task in the repo
 	 * before the run starts.
 	 *
-	 * @param joinPoint
+	 * @param joinPoint the point where the run method in a {@link CommandLineRunner} or
+	 *                     {@link ApplicationRunner} is executed
 	 */
 	@Before("within( @org.springframework.cloud.task.annotation.Task *) && (execution(* org.springframework.boot.CommandLineRunner.run(..)) || execution(* org.springframework.boot.ApplicationRunner.run(..)))")
 	public void beforeCommandLineRunner(JoinPoint joinPoint) {
@@ -78,11 +82,12 @@ public class TaskHandler {
 	}
 
 	/**
-	 * Looks for any CommandLineRunner.run method with its class annotated with @Task
+	 * Looks for any {@link CommandLineRunner}.run method with its class annotated with @Task
 	 * and calls repository implementation to store the exit of the task in the repo after
 	 * run returns result.
 	 *
-	 * @param joinPoint
+	 * @param joinPoint the point where the run method in a {@link CommandLineRunner} or
+	 *                     {@link ApplicationRunner} is executed
 	 */
 	@AfterReturning("within( @org.springframework.cloud.task.annotation.Task *) && (execution(* org.springframework.boot.CommandLineRunner.run(..)) || execution(* org.springframework.boot.ApplicationRunner.run(..)))")
 	public void afterReturnCommandLineRunner(JoinPoint joinPoint) {
@@ -99,11 +104,12 @@ public class TaskHandler {
 	}
 
 	/**
-	 * Looks for any CommandLineRunner. run method with its class annotated with @Task
+	 * Looks for any {@link CommandLineRunner}.run method with its class annotated with @Task
 	 * and calls the repository implementation to store the exitCode of 1
 	 * for the task in the repo in the case of an exception.
 	 *
-	 * @param joinPoint
+	 * @param joinPoint the point where the run method in a {@link CommandLineRunner} or
+	 *                     {@link ApplicationRunner} is executed
 	 */
 	@AfterThrowing("within( @org.springframework.cloud.task.annotation.Task *) && (execution(* org.springframework.boot.CommandLineRunner.run(..)) || execution(* org.springframework.boot.ApplicationRunner.run(..)))")
 	public void logExceptionCommandLineRunner(JoinPoint joinPoint) {
@@ -112,4 +118,7 @@ public class TaskHandler {
 		repository.update(taskExecution);
 	}
 
+	public TaskExecution getTaskExecution() {
+		return taskExecution;
+	}
 }

spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/TaskRepository.java

@@ -18,7 +18,7 @@ package org.springframework.cloud.task.repository;
 
 /**
  * TaskRepository interface offers methods that create and update task execution
- * information.  The interface will support the following methods:
+ * information.
  *
  * @author Glenn Renfro
  */

spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/support/LoggerTaskRepository.java

@@ -24,6 +24,8 @@ import org.springframework.cloud.task.repository.TaskExecution;
 import org.springframework.cloud.task.repository.TaskRepository;
 
 /**
+ * {@link TaskRepository} implementation that will log the task execution information.
+ *
  * @author Glenn Renfro
  */
 public class LoggerTaskRepository implements TaskRepository {