Merge pull request #6651 from vpavic:improve-batch-autoconfig

* pr/6651:
  Polish contribution
  Validate Spring Batch database initializer configuration

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/batch/BatchProperties.java

 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 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.
@@ -23,6 +23,7 @@ import org.springframework.boot.context.properties.ConfigurationProperties;
  *
  * @author Stephane Nicoll
  * @author Eddú Meléndez
+ * @author Vedran Pavic
  * @since 1.2.0
  */
 @ConfigurationProperties("spring.batch")
@@ -69,15 +70,23 @@ public class BatchProperties {
 		return this.tablePrefix;
 	}
 
-	public static class Initializer {
+	public class Initializer {
 
 		/**
-		 * Create the required batch tables on startup if necessary.
+		 * Create the required batch tables on startup if necessary. Enabled
+		 * automatically if no custom table prefix is set or if a custom schema is
+		 * configured.
 		 */
-		private boolean enabled = true;
+		private Boolean enabled;
 
 		public boolean isEnabled() {
-			return this.enabled;
+			if (this.enabled != null) {
+				return this.enabled;
+			}
+			boolean defaultTablePrefix = BatchProperties.this.getTablePrefix() == null;
+			boolean customSchema = !DEFAULT_SCHEMA_LOCATION.equals(
+					BatchProperties.this.getSchema());
+			return (defaultTablePrefix || customSchema);
 		}
 
 		public void setEnabled(boolean enabled) {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/batch/BatchAutoConfigurationTests.java

@@ -67,6 +67,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Dave Syer
  * @author Stephane Nicoll
+ * @author Vedran Pavic
  */
 public class BatchAutoConfigurationTests {
 
@@ -91,6 +92,8 @@ public class BatchAutoConfigurationTests {
 		this.context.refresh();
 		assertThat(this.context.getBean(JobLauncher.class)).isNotNull();
 		assertThat(this.context.getBean(JobExplorer.class)).isNotNull();
+		assertThat(this.context.getBean(BatchProperties.class)
+				.getInitializer().isEnabled()).isTrue();
 		assertThat(new JdbcTemplate(this.context.getBean(DataSource.class))
 				.queryForList("select * from BATCH_JOB_EXECUTION")).isEmpty();
 	}
@@ -190,6 +193,8 @@ public class BatchAutoConfigurationTests {
 				PropertyPlaceholderAutoConfiguration.class);
 		this.context.refresh();
 		assertThat(this.context.getBean(JobLauncher.class)).isNotNull();
+		assertThat(this.context.getBean(BatchProperties.class)
+				.getInitializer().isEnabled()).isFalse();
 		this.expected.expect(BadSqlGrammarException.class);
 		new JdbcTemplate(this.context.getBean(DataSource.class))
 				.queryForList("select * from BATCH_JOB_EXECUTION");
@@ -228,6 +233,8 @@ public class BatchAutoConfigurationTests {
 				PropertyPlaceholderAutoConfiguration.class);
 		this.context.refresh();
 		assertThat(this.context.getBean(JobLauncher.class)).isNotNull();
+		assertThat(this.context.getBean(BatchProperties.class)
+				.getInitializer().isEnabled()).isTrue();
 		assertThat(new JdbcTemplate(this.context.getBean(DataSource.class))
 				.queryForList("select * from PREFIX_JOB_EXECUTION")).isEmpty();
 		JobExplorer jobExplorer = this.context.getBean(JobExplorer.class);
@@ -237,6 +244,25 @@ public class BatchAutoConfigurationTests {
 				.isNull();
 	}
 
+	@Test
+	public void testCustomTablePrefixWithDefaultSchemaDisablesInitializer() throws Exception {
+		this.context = new AnnotationConfigApplicationContext();
+		EnvironmentTestUtils.addEnvironment(this.context,
+				"spring.datasource.name:batchtest",
+				"spring.batch.tablePrefix:PREFIX_");
+		this.context.register(TestConfiguration.class,
+				EmbeddedDataSourceConfiguration.class,
+				HibernateJpaAutoConfiguration.class, BatchAutoConfiguration.class,
+				PropertyPlaceholderAutoConfiguration.class);
+		this.context.refresh();
+		assertThat(this.context.getBean(JobLauncher.class)).isNotNull();
+		assertThat(this.context.getBean(BatchProperties.class)
+				.getInitializer().isEnabled()).isFalse();
+		this.expected.expect(BadSqlGrammarException.class);
+		new JdbcTemplate(this.context.getBean(DataSource.class))
+				.queryForList("select * from BATCH_JOB_EXECUTION");
+	}
+
 	@Configuration
 	protected static class EmptyConfiguration {
 	}

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -847,7 +847,7 @@ content into your application; rather pick only the properties that you need.
 	spring.artemis.user= # Login user of the broker.
 
 	# SPRING BATCH ({sc-spring-boot-autoconfigure}/batch/BatchProperties.{sc-ext}[BatchProperties])
-	spring.batch.initializer.enabled=true # Create the required batch tables on startup if necessary.
+	spring.batch.initializer.enabled= # Create the required batch tables on startup if necessary. Enabled automatically if no custom table prefix is set or if a custom schema is configured.
 	spring.batch.job.enabled=true # Execute all Spring Batch jobs in the context on startup.
 	spring.batch.job.names= # Comma-separated list of job names to execute on startup (For instance `job1,job2`). By default, all Jobs found in the context are executed.
 	spring.batch.schema=classpath:org/springframework/batch/core/schema-@@platform@@.sql # Path to the SQL file to use to initialize the database schema.