Refactored database initialization

This commit introduces the `TaskRepositoryInitializer` component.  This
component will initialize the `DataSource` when appropriate and silently do
nothing otherwise.  It can be customized to initialize a specific
`DataSource` as required.

Resolves spring-cloud/spring-cloud-task#84

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2016 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.
@@ -25,26 +25,25 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.ApplicationArguments;
 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.cloud.task.repository.support.TaskRepositoryInitializer;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.core.io.ResourceLoader;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.transaction.annotation.EnableTransactionManagement;
 
 /**
  * Base {@code Configuration} class providing common structure for enabling and using
- * Spring Task. Customization is
- * available by implementing the {@link TaskConfigurer} interface.
+ * Spring Task. Customization is available by implementing the {@link TaskConfigurer}
+ * interface.
  *
  * @author Glenn Renfro
+ * @author Michael Minella
  */
 @Configuration
 @EnableTransactionManagement
@@ -58,15 +57,9 @@ public class SimpleTaskConfiguration {
 	@Autowired(required = false)
 	private Collection<DataSource> dataSources;
 
-	@Autowired
-	private ResourceLoader resourceLoader;
-
 	@Autowired(required = false)
 	private ApplicationArguments applicationArguments;
 
-	@Value("${spring.class.initialize.enable:true}")
-	private boolean taskInitializationEnable;
-
 	private boolean initialized = false;
 
 	private TaskRepository taskRepository;
@@ -95,6 +88,17 @@ public class SimpleTaskConfiguration {
 		return new SimpleTaskNameResolver();
 	}
 
+	@Bean
+	public TaskRepositoryInitializer taskRepositoryInitializer() {
+		TaskRepositoryInitializer taskRepositoryInitializer = new TaskRepositoryInitializer();
+
+		if(this.dataSources != null && this.dataSources.size() == 1) {
+			taskRepositoryInitializer.setDataSource(this.dataSources.iterator().next());
+		}
+
+		return taskRepositoryInitializer;
+	}
+
 	/**
 	 * 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.
@@ -116,7 +120,7 @@ public class SimpleTaskConfiguration {
 	}
 
 	private TaskConfigurer getDefaultConfigurer(Collection<TaskConfigurer> configurers) {
-		boolean isDataSourceConfigured = (dataSources != null && !dataSources.isEmpty());
+		boolean isDataSourceConfigured = (dataSources != null && dataSources.size() == 1);
 		verifyEnvironment(configurers);
 		if (configurers == null || configurers.isEmpty()) {
 			if (!isDataSourceConfigured) {
@@ -124,12 +128,7 @@ public class SimpleTaskConfiguration {
 				return this.configurer;
 			}
 			else {
-				DataSource dataSource = dataSources.iterator().next();
-				if(taskInitializationEnable) {
-					logger.debug("Initializing Task Schema");
-					TaskDatabaseInitializer.initializeDatabase(dataSource, resourceLoader);
-				}
-				this.configurer = new DefaultTaskConfigurer(dataSource);
+				this.configurer = new DefaultTaskConfigurer(this.dataSources.iterator().next());
 				return this.configurer;
 			}
 		}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2016 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.
@@ -20,18 +20,32 @@ import javax.sql.DataSource;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.jdbc.datasource.init.DatabasePopulatorUtils;
 import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;
 import org.springframework.jdbc.support.MetaDataAccessException;
 
 /**
+ * Utility for initializing the Task Repository's datasource.  If a single
+ * {@link DataSource} is available in the current context, and functionality is enabled
+ * (as it is by default), this will initialize the database.  If more than one DataSource
+ * is available in the current context, custom configuration of this is required
+ * (if desired).
+ *
+ * By default, initialization of the database can be disabled by configuring the property
+ * <code>spring.cloud.task.initialize.enable</code> to false.
+ *
  * @author Glenn Renfro
+ * @author Michael Minella
  */
 
-public final class TaskDatabaseInitializer {
+public final class TaskRepositoryInitializer implements InitializingBean {
 
-	private static final Log logger = LogFactory.getLog(TaskDatabaseInitializer.class);
+	private static final Log logger = LogFactory.getLog(TaskRepositoryInitializer.class);
 
 	private static final String DEFAULT_SCHEMA_LOCATION = "classpath:org/springframework/"
 			+ "cloud/task/schema-@@platform@@.sql";
@@ -41,12 +55,37 @@ public final class TaskDatabaseInitializer {
 	 */
 	private static String schema = DEFAULT_SCHEMA_LOCATION;
 
-	private TaskDatabaseInitializer(){
+	private DataSource dataSource;
 
+	private ResourceLoader resourceLoader;
+
+	@Value("${spring.cloud.task.initialize.enable:true}")
+	private boolean taskInitializationEnable;
+
+	public TaskRepositoryInitializer(){
 	}
 
-	public static void initializeDatabase(DataSource dataSource, ResourceLoader resourceLoader) {
-		if (dataSource != null) {
+	public void setDataSource(DataSource dataSource) {
+		this.dataSource = dataSource;
+	}
+
+	@Autowired(required = false)
+	public void setResourceLoader(ResourceLoader resourceLoader) {
+		this.resourceLoader = resourceLoader;
+	}
+
+	private String getDatabaseType(DataSource dataSource) {
+		try {
+			return DatabaseType.fromMetaData(dataSource).toString().toLowerCase();
+		}
+		catch (MetaDataAccessException ex) {
+			throw new IllegalStateException("Unable to detect database type", ex);
+		}
+	}
+
+	@Override
+	public void afterPropertiesSet() throws Exception {
+		if (dataSource != null && taskInitializationEnable) {
 			String platform = getDatabaseType(dataSource);
 			if ("hsql".equals(platform)) {
 				platform = "hsqldb";
@@ -70,14 +109,4 @@ public final class TaskDatabaseInitializer {
 			DatabasePopulatorUtils.execute(populator, dataSource);
 		}
 	}
-
-	private static String getDatabaseType(DataSource dataSource) {
-		try {
-			return DatabaseType.fromMetaData(dataSource).toString().toLowerCase();
-		}
-		catch (MetaDataAccessException ex) {
-			throw new IllegalStateException("Unable to detect database type", ex);
-		}
-	}
-
 }