Added TaskNameResolver and related implementation

TaskNameResolver allows the ability to customize how a task is named.
During normal use cases, the provided SimpleTaskNameResolver should
suffice.

resolves spring-cloud/spring-cloud-task#54

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

@@ -27,7 +27,9 @@ import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.cloud.task.listener.TaskLifecycleListener;
+import org.springframework.cloud.task.repository.TaskNameResolver;
 import org.springframework.cloud.task.repository.TaskRepository;
+import org.springframework.cloud.task.repository.support.SimpleTaskNameResolver;
 import org.springframework.cloud.task.repository.support.TaskDatabaseInitializer;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
@@ -76,7 +78,7 @@ public class SimpleTaskConfiguration {
 
 	@Bean
 	public TaskLifecycleListener taskLifecycleListener() {
-		return new TaskLifecycleListener(taskRepository());
+		return new TaskLifecycleListener(taskRepository(), taskNameResolver());
 	}
 
 	@Bean
@@ -84,6 +86,11 @@ public class SimpleTaskConfiguration {
 		return this.transactionManager;
 	}
 
+	@Bean
+	public TaskNameResolver taskNameResolver() {
+		return new SimpleTaskNameResolver();
+	}
+
 	/**
 	 * 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.

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

@@ -33,9 +33,9 @@ public interface TaskConfigurer {
 	 *
 	 * @return A TaskRepository
 	 */
-	public TaskRepository getTaskRepository();
+	TaskRepository getTaskRepository();
 
-	public PlatformTransactionManager getTransactionManager();
+	PlatformTransactionManager getTransactionManager();
 
-	public TaskExplorer getTaskExplorer();
+	TaskExplorer getTaskExplorer();
 }

spring-cloud-task-core/src/main/java/org/springframework/cloud/task/listener/TaskLifecycleListener.java

@@ -23,16 +23,15 @@ import java.util.UUID;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import org.springframework.beans.BeansException;
 import org.springframework.boot.context.event.ApplicationFailedEvent;
 import org.springframework.cloud.task.repository.TaskExecution;
+import org.springframework.cloud.task.repository.TaskNameResolver;
 import org.springframework.cloud.task.repository.TaskRepository;
-import org.springframework.context.ApplicationContext;
-import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.event.ContextClosedEvent;
 import org.springframework.context.event.ContextRefreshedEvent;
+import org.springframework.util.Assert;
 
 /**
  * Monitors the lifecycle of a task.  This listener will record both the start and end of
@@ -52,8 +51,7 @@ import org.springframework.context.event.ContextRefreshedEvent;
  *
  * @author Michael Minella
  */
-public class TaskLifecycleListener implements ApplicationListener<ApplicationEvent>,
-		ApplicationContextAware {
+public class TaskLifecycleListener implements ApplicationListener<ApplicationEvent>{
 
 	private final static Logger logger = LoggerFactory.getLogger(TaskLifecycleListener.class);
 
@@ -63,13 +61,18 @@ public class TaskLifecycleListener implements ApplicationListener<ApplicationEve
 
 	private boolean started = false;
 
-	private ApplicationContext applicationContext;
+	private TaskNameResolver taskNameResolver;
 
 	/**
 	 * @param taskRepository The repository to record executions in.
 	 */
-	public TaskLifecycleListener(TaskRepository taskRepository) {
+	public TaskLifecycleListener(TaskRepository taskRepository,
+			TaskNameResolver taskNameResolver) {
+		Assert.notNull(taskRepository, "A taskRepository is required");
+		Assert.notNull(taskNameResolver, "A taskNameResolver is required");
+
 		this.taskRepository = taskRepository;
+		this.taskNameResolver = taskNameResolver;
 	}
 
 	/**
@@ -143,7 +146,7 @@ public class TaskLifecycleListener implements ApplicationListener<ApplicationEve
 			String executionId = UUID.randomUUID().toString();
 			this.taskExecution = new TaskExecution();
 
-			this.taskExecution.setTaskName(applicationContext.getId());
+			this.taskExecution.setTaskName(taskNameResolver.getTaskName());
 			this.taskExecution.setStartTime(new Date());
 			this.taskExecution.setExecutionId(executionId);
 			this.taskRepository.createTaskExecution(this.taskExecution);
@@ -161,10 +164,4 @@ public class TaskLifecycleListener implements ApplicationListener<ApplicationEve
 	TaskExecution getTaskExecution() {
 		return this.taskExecution;
 	}
-
-	@Override
-	public void setApplicationContext(ApplicationContext applicationContext)
-			throws BeansException {
-		this.applicationContext = applicationContext;
-	}
 }

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

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2016 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.repository;
+
+/**
+ * Strategy interface for customizing how the name of a task is determined.
+ *
+ * @author Michael Minella
+ */
+public interface TaskNameResolver {
+
+	/**
+	 * @return the name of the task being executed within this context.
+	 */
+	String getTaskName();
+}

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

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2016 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.repository.support;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.cloud.task.repository.TaskNameResolver;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+import org.springframework.util.StringUtils;
+
+/**
+ * Simple implementation of the {@link TaskNameResolver} interface.  Names the task based
+ * on the following order of precidence:
+ * <ol>
+ *    <li>A configured property <code>spring.cloud.task.name</code></li>
+ *    <li>The {@link ApplicationContext}'s id.</li>
+ * </ol>
+ *
+ * @author Michael Minella
+ * @see org.springframework.boot.context.ContextIdApplicationContextInitializer
+ */
+public class SimpleTaskNameResolver implements TaskNameResolver, ApplicationContextAware {
+
+	private ApplicationContext context;
+
+	private String configuredName;
+
+	@Value("${spring.cloud.task.name:}")
+	public void setConfiguredName(String configuredName) {
+		this.configuredName = configuredName;
+	}
+
+	@Override
+	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
+		this.context = applicationContext;
+	}
+
+	@Override
+	public String getTaskName() {
+		if(StringUtils.hasText(configuredName)) {
+			return configuredName;
+		}
+		else {
+			return context.getId();
+		}
+	}
+}