RESOLVED - issue BATCH-1395: Remove or deprecate old application context creation pattern

Removed it.

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/ApplicationContextJobFactory.java

@@ -54,7 +54,7 @@ public class ApplicationContextJobFactory implements JobFactory {
 	public Job createJob() {
 		ConfigurableApplicationContext context = applicationContextFactory.createApplicationContext();
 		Job job = (Job) context.getBean(jobName, Job.class);
-		return new ContextClosingJob(job, context);
+		return new ContextAwareJob(job);
 	}
 
 	/**
@@ -72,19 +72,15 @@ public class ApplicationContextJobFactory implements JobFactory {
 	 * @author Dave Syer
 	 * 
 	 */
-	private static class ContextClosingJob implements Job {
+	private static class ContextAwareJob implements Job {
 		private Job delegate;
 
-		private ConfigurableApplicationContext context;
-
 		/**
 		 * @param delegate
-		 * @param context
 		 */
-		public ContextClosingJob(Job delegate, ConfigurableApplicationContext context) {
+		public ContextAwareJob(Job delegate) {
 			super();
 			this.delegate = delegate;
-			this.context = context;
 		}
 
 		/**
@@ -92,12 +88,7 @@ public class ApplicationContextJobFactory implements JobFactory {
 		 * @see org.springframework.batch.core.Job#execute(org.springframework.batch.core.JobExecution)
 		 */
 		public void execute(JobExecution execution) {
-			try {
-				delegate.execute(execution);
-			}
-			finally {
-				context.close();
-			}
+			delegate.execute(execution);
 		}
 
 		/**

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/ClassPathXmlApplicationContextFactory.java

@@ -25,10 +25,12 @@ import org.springframework.core.io.Resource;
 import org.springframework.util.Assert;
 
 /**
- * {@link ApplicationContextFactory} implementation that takes a parent context and a path 
- * to the context to create.  Each time the createApplicationContext method is called, a new
- * {@link ApplicationContext} will be returned.  It should be noted that if a path isn't
- * set, the parent will always be returned.
+ * {@link ApplicationContextFactory} implementation that takes a parent context
+ * and a path to the context to create. When createApplicationContext method is
+ * called, the child {@link ApplicationContext} will be returned. The child
+ * context is not re-created every time it is requested, it is lazily
+ * initialized and cached. Clients should ensure that it is closed when it is no
+ * longer needed. If a path is not set, the parent will always be returned.
  * 
  */
 public class ClassPathXmlApplicationContextFactory implements ApplicationContextFactory, ApplicationContextAware {
@@ -37,10 +39,14 @@ public class ClassPathXmlApplicationContextFactory implements ApplicationContext
 
 	private Resource path;
 
+	private ResourceXmlApplicationContext context;
+
+	private final Object lock = new Object();
+
 	/**
 	 * Setter for the path to the xml to load to create an
-	 * {@link ApplicationContext}. Use imports to centralise the configuration in
-	 * one file.
+	 * {@link ApplicationContext}. Use imports to centralise the configuration
+	 * in one file.
 	 * 
 	 * @param path the resource path to the xml to load for the child context.
 	 */
@@ -64,10 +70,21 @@ public class ClassPathXmlApplicationContextFactory implements ApplicationContext
 	 * @see ApplicationContextFactory#createApplicationContext()
 	 */
 	public ConfigurableApplicationContext createApplicationContext() {
+
 		if (path == null) {
 			return parent;
 		}
-		return new ResourceXmlApplicationContext(parent);
+
+		if (context == null) {
+			// Lazy initialization of cached context
+			synchronized (lock) {
+				if (context == null) {
+					context = new ResourceXmlApplicationContext(parent);
+				}
+			}
+		}
+		return context;
+
 	}
 
 	/**
@@ -84,7 +101,7 @@ public class ClassPathXmlApplicationContextFactory implements ApplicationContext
 		}
 
 		protected Resource[] getConfigResources() {
-			return new Resource[] {path};
+			return new Resource[] { path };
 		}
 	}
 

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/ClassPathXmlJobRegistry.java

@@ -18,6 +18,7 @@ package org.springframework.batch.core.configuration.support;
 
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.List;
 
 import org.apache.commons.logging.Log;
@@ -28,20 +29,26 @@ import org.springframework.batch.core.configuration.JobFactory;
 import org.springframework.batch.core.configuration.ListableJobRegistry;
 import org.springframework.batch.core.launch.NoSuchJobException;
 import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.io.Resource;
 
 /**
  * Implementation of the {@link ListableJobRegistry} interface that assumes all
- * Jobs will be loaded from ClassPathXml resources.
+ * Jobs will be loaded from class path xml resources. Each resource provided is
+ * loaded as an application context with the current context as its parent, and
+ * then all the jobs from the child context are registered under their bean
+ * names. Care must be taken to avoid duplicate names.
  * 
  * @author Lucas Ward
  * @author Dave Syer
  * @since 2.0
  */
-public class ClassPathXmlJobRegistry implements ListableJobRegistry, ApplicationContextAware, InitializingBean {
+public class ClassPathXmlJobRegistry implements ListableJobRegistry, ApplicationContextAware, InitializingBean,
+		DisposableBean {
 
 	private static Log logger = LogFactory.getLog(ClassPathXmlJobRegistry.class);
 
@@ -51,25 +58,59 @@ public class ClassPathXmlJobRegistry implements ListableJobRegistry, Application
 
 	private ListableJobRegistry jobRegistry = new MapJobRegistry();
 
+	private Collection<ConfigurableApplicationContext> contexts = new HashSet<ConfigurableApplicationContext>();
+
+	/**
+	 * A set of resources to load. Each resource should be a Spring
+	 * configuration file which is loaded into an application context whose
+	 * parent is the current context. In a configuration file the resources can
+	 * be given as a pattern (e.g.
+	 * <code>classpath*:/config/*-job-context.xml</code>).
+	 * 
+	 * @param jobPaths
+	 */
 	public void setJobPaths(Resource[] jobPaths) {
 		this.jobPaths = Arrays.asList(jobPaths);
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see
+	 * org.springframework.context.ApplicationContextAware#setApplicationContext
+	 * (org.springframework.context.ApplicationContext)
+	 */
 	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
 		parent = applicationContext;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see
+	 * org.springframework.batch.core.configuration.JobLocator#getJob(java.lang
+	 * .String)
+	 */
 	public Job getJob(String name) throws NoSuchJobException {
 		return jobRegistry.getJob(name);
 	}
 
+	/**
+	 * Create all the application contexts required and set up job registry
+	 * entries with all the instances of {@link Job} found therein.
+	 * 
+	 * @see InitializingBean#afterPropertiesSet()
+	 */
 	public void afterPropertiesSet() throws Exception {
 
 		for (Resource resource : jobPaths) {
 			ClassPathXmlApplicationContextFactory applicationContextFactory = new ClassPathXmlApplicationContextFactory();
 			applicationContextFactory.setPath(resource);
-			applicationContextFactory.setApplicationContext(parent);
-			ApplicationContext context = applicationContextFactory.createApplicationContext();
+			if (parent != null) {
+				applicationContextFactory.setApplicationContext(parent);
+			}
+			ConfigurableApplicationContext context = applicationContextFactory.createApplicationContext();
+			contexts.add(context);
 			String[] names = context.getBeanNamesForType(Job.class);
 
 			for (String name : names) {
@@ -86,6 +127,35 @@ public class ClassPathXmlJobRegistry implements ListableJobRegistry, Application
 
 	}
 
+	/**
+	 * Close the contexts that were created in {@link #afterPropertiesSet()}.
+	 * 
+	 * @see DisposableBean#destroy()
+	 */
+	public void destroy() throws Exception {
+
+		try {
+
+			for (ConfigurableApplicationContext context : contexts) {
+
+				String[] names = context.getBeanNamesForType(Job.class);
+
+				try {
+					for (String name : names) {
+						unregister(name);
+					}
+				}
+				finally {
+					context.close();
+				}
+
+			}
+		}
+		finally {
+			contexts.clear();
+		}
+	}
+
 	public Collection<String> getJobNames() {
 		return jobRegistry.getJobNames();
 	}

spring-batch-core/src/test/java/org/springframework/batch/core/configuration/support/ClassPathXmlJobRegistryTests.java

@@ -70,4 +70,18 @@ public class ClassPathXmlJobRegistryTests {
 		registry.afterPropertiesSet();
 		assertEquals(2, registry.getJobNames().size());
 	}
+
+	@Test
+	public void testDestroy() throws Exception {
+
+		Resource[] jobPaths = new Resource[] { new ClassPathResource(
+				"org/springframework/batch/core/launch/support/2jobs.xml") };
+		registry.setJobPaths(jobPaths);
+		registry.afterPropertiesSet();
+		assertEquals(2, registry.getJobNames().size());
+		registry.destroy();
+		assertEquals(0, registry.getJobNames().size());
+
+	}
+
 }

spring-batch-samples/src/main/resources/jobs/skipSampleJob.xml

@@ -88,13 +88,13 @@
 		</property>
 	</bean>
 
-	<bean id="tradeProcessor" class="org.springframework.batch.sample.domain.trade.internal.TradeProcessor" />
+	<bean id="tradeProcessor" class="org.springframework.batch.sample.domain.trade.internal.TradeProcessor" scope="step"/>
 
-	<bean id="tradeProcessorFailure" class="org.springframework.batch.sample.domain.trade.internal.TradeProcessor">
+	<bean id="tradeProcessorFailure" class="org.springframework.batch.sample.domain.trade.internal.TradeProcessor" scope="step">
 		<property name="validationFailure" value="7" />
 	</bean>
 
-	<bean id="tradeWriter" class="org.springframework.batch.sample.domain.trade.internal.TradeWriter">
+	<bean id="tradeWriter" class="org.springframework.batch.sample.domain.trade.internal.TradeWriter" scope="step">
 		<property name="dao">
 			<bean class="org.springframework.batch.sample.domain.trade.internal.JdbcTradeDao">
 				<property name="dataSource" ref="dataSource" />
@@ -112,12 +112,12 @@
 		</property>
 	</bean>
 
-	<bean id="itemTrackingWriter" class="org.springframework.batch.sample.domain.trade.internal.ItemTrackingTradeItemWriter">
+	<bean id="itemTrackingWriter" class="org.springframework.batch.sample.domain.trade.internal.ItemTrackingTradeItemWriter" scope="step">
 		<property name="writeFailureISIN" value="UK21341EAH47" />
 		<property name="dataSource" ref="dataSource" />
 	</bean>
 
-	<bean id="tradeSqlItemReader" class="org.springframework.batch.item.database.JdbcCursorItemReader">
+	<bean id="tradeSqlItemReader" class="org.springframework.batch.item.database.JdbcCursorItemReader" scope="step">
 		<property name="dataSource" ref="dataSource" />
 		<property name="sql" value="SELECT isin, quantity, price, customer, id, version from TRADE" />
 		<property name="rowMapper">
@@ -125,7 +125,7 @@
 		</property>
 	</bean>
 
-	<bean id="errorLogTasklet" class="org.springframework.batch.sample.common.ErrorLogTasklet">
+	<bean id="errorLogTasklet" class="org.springframework.batch.sample.common.ErrorLogTasklet" scope="step">
 		<property name="dataSource" ref="dataSource" />
 	</bean>