BATCH-1474: Added reload() feature to JobLoader.

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

@@ -53,14 +53,27 @@ public class ClassPathXmlApplicationContextFactory implements ApplicationContext
 	private Resource resource;
 
 	private ConfigurableApplicationContext parent;
-	
+
 	private boolean copyConfiguration = true;
 
 	private Collection<Class<? extends BeanFactoryPostProcessor>> beanFactoryPostProcessorClasses;
 
 	private Collection<Class<?>> beanPostProcessorExcludeClasses;
 
+	/**
+	 * Convenient constructor for configuration purposes.
+	 */
 	public ClassPathXmlApplicationContextFactory() {
+		this(null);
+	}
+
+	/**
+	 * Create a factory instance with the resource specified. The resource is a
+	 * Spring XML configuration file.
+	 */
+	public ClassPathXmlApplicationContextFactory(Resource resource) {
+
+		this.resource = resource;
 		beanFactoryPostProcessorClasses = new ArrayList<Class<? extends BeanFactoryPostProcessor>>();
 		beanFactoryPostProcessorClasses.add(PropertyPlaceholderConfigurer.class);
 		beanFactoryPostProcessorClasses.add(CustomEditorConfigurer.class);
@@ -80,7 +93,8 @@ public class ClassPathXmlApplicationContextFactory implements ApplicationContext
 	 * {@link ApplicationContext}. Use imports to centralise the configuration
 	 * in one file.
 	 * 
-	 * @param resource the resource path to the xml to load for the child context.
+	 * @param resource the resource path to the xml to load for the child
+	 * context.
 	 */
 	public void setResource(Resource resource) {
 		this.resource = resource;
@@ -156,7 +170,7 @@ public class ClassPathXmlApplicationContextFactory implements ApplicationContext
 	 * @see org.springframework.context.ApplicationContextAware#setApplicationContext(org.springframework.context.ApplicationContext)
 	 */
 	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
-		if (applicationContext==null) {
+		if (applicationContext == null) {
 			return;
 		}
 		Assert.isInstanceOf(ConfigurableApplicationContext.class, applicationContext);
@@ -270,4 +284,24 @@ public class ClassPathXmlApplicationContextFactory implements ApplicationContext
 			}
 		}
 	}
+
+	@Override
+	public String toString() {
+		return "ClassPathXmlApplicationContextFactory [resource=" + resource + "]";
+	}
+
+	@Override
+	public int hashCode() {
+		return toString().hashCode();
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		return toString().equals(obj.toString());
+	}
+
 }

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

@@ -18,6 +18,8 @@ package org.springframework.batch.core.configuration.support;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -29,6 +31,9 @@ import org.springframework.batch.core.launch.NoSuchJobException;
 import org.springframework.context.ConfigurableApplicationContext;
 
 /**
+ * Default implementation of {@link JobLoader}. Uses a {@link JobRegistry} to
+ * manage a population of loaded jobs and clears them up when asked.
+ * 
  * @author Dave Syer
  * 
  */
@@ -38,10 +43,12 @@ public class DefaultJobLoader implements JobLoader {
 
 	private JobRegistry jobRegistry;
 
-	private Collection<ConfigurableApplicationContext> contexts = new HashSet<ConfigurableApplicationContext>();
-	
+	private Map<ApplicationContextFactory, ConfigurableApplicationContext> contexts = new ConcurrentHashMap<ApplicationContextFactory, ConfigurableApplicationContext>();
+
+	private Map<ConfigurableApplicationContext, Collection<String>> contextToJobNames = new ConcurrentHashMap<ConfigurableApplicationContext, Collection<String>>();
+
 	/**
-	 * Default constructor useful for declarative configuration. 
+	 * Default constructor useful for declarative configuration.
 	 */
 	public DefaultJobLoader() {
 		this(null);
@@ -71,7 +78,7 @@ public class DefaultJobLoader implements JobLoader {
 	 * @see JobLoader#clear()
 	 */
 	public void clear() {
-		for (ConfigurableApplicationContext context : contexts) {
+		for (ConfigurableApplicationContext context : contexts.values()) {
 			if (context.isActive()) {
 				context.close();
 			}
@@ -82,22 +89,68 @@ public class DefaultJobLoader implements JobLoader {
 		contexts.clear();
 	}
 
+	public Collection<Job> reload(ApplicationContextFactory factory) {
+
+		// If the same factory is loaded twice the context can be closed
+		if (contexts.containsKey(factory)) {
+			ConfigurableApplicationContext context = contexts.get(factory);
+			for (String name : contextToJobNames.get(context)) {
+				logger.debug("Unregistering job: " + name + " from context: " + context.getDisplayName());
+				jobRegistry.unregister(name);
+			}
+			context.close();
+		}
+
+		try {
+			return doLoad(factory, true);
+		}
+		catch (DuplicateJobException e) {
+			throw new IllegalStateException("Found duplicte job in reload (it should have been unregistered "
+					+ "if it was previously registered in this loader)", e);
+		}
+	}
+
 	public Collection<Job> load(ApplicationContextFactory factory) throws DuplicateJobException {
+		return doLoad(factory, false);
+	}
+
+	private Collection<Job> doLoad(ApplicationContextFactory factory, boolean unregister) throws DuplicateJobException {
 
 		Collection<String> jobNamesBefore = jobRegistry.getJobNames();
 		ConfigurableApplicationContext context = factory.createApplicationContext();
+		Collection<String> jobNamesAfter = jobRegistry.getJobNames();
 		// Try to detect auto-registration (e.g. through a bean post processor)
-		boolean autoRegistrationDetected = jobRegistry.getJobNames().size() > jobNamesBefore.size();
+		boolean autoRegistrationDetected = jobNamesAfter.size() > jobNamesBefore.size();
 
-		contexts.add(context);
+		Collection<String> jobsRegistered = new HashSet<String>();
+		if (autoRegistrationDetected) {
+			for (String name : jobNamesAfter) {
+				if (!jobNamesBefore.contains(name)) {
+					jobsRegistered.add(name);
+				}
+			}
+		}
+
+		contexts.put(factory, context);
 		String[] names = context.getBeanNamesForType(Job.class);
+
 		Collection<Job> result = new ArrayList<Job>();
 
 		for (String name : names) {
+
 			if (!autoRegistrationDetected) {
+
+				// On reload try to unregister first
+				if (unregister) {
+					logger.debug("Unregistering job: " + name + " from context: " + context.getDisplayName());
+					jobRegistry.unregister(name);
+				}
+
 				logger.debug("Registering job: " + name + " from context: " + context.getDisplayName());
 				JobFactory jobFactory = new ReferenceJobFactory((Job) context.getBean(name));
 				jobRegistry.register(jobFactory);
+				jobsRegistered.add(name);
+
 			}
 			try {
 				result.add(jobRegistry.getJob(name));
@@ -106,8 +159,11 @@ public class DefaultJobLoader implements JobLoader {
 				// should not happen;
 				throw new IllegalStateException("Could not retrieve job that was should have been registered", e);
 			}
+
 		}
 
+		contextToJobNames.put(context, jobsRegistered);
+
 		return result;
 
 	}

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

@@ -20,25 +20,42 @@ import java.util.Collection;
 import org.springframework.batch.core.Job;
 import org.springframework.batch.core.configuration.DuplicateJobException;
 
-
 /**
  * @author Dave Syer
  * 
  * @since 2.1
  */
 public interface JobLoader {
-	
+
 	/**
+	 * Load an application context and register all the jobs.
+	 * 
 	 * @param factory a factory for an application context (containing jobs)
 	 * @return a collection of the jobs created
 	 * 
-	 * @throws DuplicateJobException if a job with the same name was already registered
+	 * @throws DuplicateJobException if a job with the same name was already
+	 * registered
 	 */
 	Collection<Job> load(ApplicationContextFactory factory) throws DuplicateJobException;
-	
+
 	/**
-	 * Unregister all the jobs and close all the contexts created by this loader.
+	 * Load an application context and register all the jobs, having first
+	 * unregistered them if already registered. Implementations should also take
+	 * care to close and clean up the application context previously created if
+	 * possible (either from this factory or from one with the same jobs).
+	 * 
+	 * @param factory a factory for an application context (containing jobs)
+	 * @return a collection of the jobs created
+	 * 
+	 * @throws DuplicateJobException if a job with the same name was already
+	 * registered
+	 */
+	Collection<Job> reload(ApplicationContextFactory factory);
+
+	/**
+	 * Unregister all the jobs and close all the contexts created by this
+	 * loader.
 	 */
 	void clear();
-	
+
 }

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

@@ -18,6 +18,8 @@ package org.springframework.batch.core.configuration.support;
 import java.util.Collection;
 import java.util.HashSet;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.springframework.batch.core.Job;
 import org.springframework.batch.core.configuration.DuplicateJobException;
 import org.springframework.batch.core.configuration.JobLocator;
@@ -45,6 +47,8 @@ import org.springframework.util.Assert;
 public class JobRegistryBeanPostProcessor implements BeanPostProcessor, BeanFactoryAware, InitializingBean,
 		DisposableBean {
 
+	private static Log logger = LogFactory.getLog(JobRegistryBeanPostProcessor.class);
+
 	// It doesn't make sense for this to have a default value...
 	private JobRegistry jobRegistry = null;
 
@@ -106,6 +110,7 @@ public class JobRegistryBeanPostProcessor implements BeanPostProcessor, BeanFact
 	 */
 	public void destroy() throws Exception {
 		for (String name : jobNames) {
+			logger.debug("Unregistering job: " + name);
 			jobRegistry.unregister(name);
 		}
 		jobNames.clear();
@@ -128,8 +133,10 @@ public class JobRegistryBeanPostProcessor implements BeanPostProcessor, BeanFact
 				}
 				job = groupName==null ? job : new GroupAwareJob(groupName, job);
 				ReferenceJobFactory jobFactory = new ReferenceJobFactory(job);
+				String name = jobFactory.getJobName();
+				logger.debug("Registering job: " + name);
 				jobRegistry.register(jobFactory);
-				jobNames.add(jobFactory.getJobName());
+				jobNames.add(name);
 			}
 			catch (DuplicateJobException e) {
 				throw new FatalBeanException("Cannot register job configuration", e);

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

@@ -91,4 +91,25 @@ public class OsgiBundleXmlApplicationContextFactory implements BundleContextAwar
 		return context;
 	}
 
+	@Override
+	public String toString() {
+		String bundleId = bundleContext == null ? null : (bundleContext.getBundle() == null ? bundleContext.toString()
+				: "" + bundleContext.getBundle().getBundleId());
+		return "OsgiBundleXmlApplicationContext [path=" + path + ", bundle=" + bundleId + "]";
+	}
+
+	@Override
+	public int hashCode() {
+		return toString().hashCode();
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		return toString().equals(obj.toString());
+	}
+
 }