Some inheritable Spring containers for experimenting

InheritableAbstractRefreshableWebApplicationContext.java

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.AbstractRefreshableConfigApplicationContext;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.ui.context.Theme;
import org.springframework.ui.context.ThemeSource;
import org.springframework.ui.context.support.UiApplicationContextUtils;
import org.springframework.web.context.ConfigurableWebApplicationContext;
import org.springframework.web.context.ConfigurableWebEnvironment;
import org.springframework.web.context.ServletConfigAware;
import org.springframework.web.context.ServletContextAware;
import org.springframework.web.context.support.ServletContextAwareProcessor;
import org.springframework.web.context.support.ServletContextResource;
import org.springframework.web.context.support.ServletContextResourcePatternResolver;
import org.springframework.web.context.support.StandardServletEnvironment;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.web.context.support.XmlWebApplicationContext;

/**
 * {@link org.springframework.context.support.AbstractRefreshableApplicationContext}
 * subclass which implements the
 * {@link org.springframework.web.context.ConfigurableWebApplicationContext}
 * interface for web environments. Provides a "configLocations" property,
 * to be populated through the ConfigurableWebApplicationContext interface
 * on web application startup.
 *
 * <p>This class is as easy to subclass as AbstractRefreshableApplicationContext:
 * All you need to implements is the {@link #loadBeanDefinitions} method;
 * see the superclass javadoc for details. Note that implementations are supposed
 * to load bean definitions from the files specified by the locations returned
 * by the {@link #getConfigLocations} method.
 *
 * <p>Interprets resource paths as servlet context resources, i.e. as paths beneath
 * the web application root. Absolute paths, e.g. for files outside the web app root,
 * can be accessed via "file:" URLs, as implemented by
 * {@link org.springframework.core.io.DefaultResourceLoader}.
 *
 * <p>In addition to the special beans detected by
 * {@link org.springframework.context.support.AbstractApplicationContext},
 * this class detects a bean of type {@link org.springframework.ui.context.ThemeSource}
 * in the context, under the special bean name "themeSource".
 *
 * <p><b>This is the web context to be subclassed for a different bean definition format.</b>
 * Such a context implementation can be specified as "contextClass" context-param
 * for {@link org.springframework.web.context.ContextLoader} or as "contextClass"
 * init-param for {@link org.springframework.web.servlet.FrameworkServlet},
 * replacing the default {@link XmlWebApplicationContext}. It will then automatically
 * receive the "contextConfigLocation" context-param or init-param, respectively.
 *
 * <p>Note that WebApplicationContext implementations are generally supposed
 * to configure themselves based on the configuration received through the
 * {@link ConfigurableWebApplicationContext} interface. In contrast, a standalone
 * application context might allow for configuration in custom startup code
 * (for example, {@link org.springframework.context.support.GenericApplicationContext}).
 *
 * @author Juergen Hoeller
 * @since 1.1.3
 * @see #loadBeanDefinitions
 * @see org.springframework.web.context.ConfigurableWebApplicationContext#setConfigLocations
 * @see org.springframework.ui.context.ThemeSource
 * @see XmlWebApplicationContext
 */
public abstract class InheritableAbstractRefreshableWebApplicationContext extends AbstractRefreshableConfigApplicationContext
  	implements ConfigurableWebApplicationContext, ThemeSource {

	/** Servlet context that this context runs in */
	private ServletContext servletContext;

	/** Servlet config that this context runs in, if any */
	private ServletConfig servletConfig;

	/** Namespace of this context, or {@code null} if root */
	private String namespace;

	/** the ThemeSource for this ApplicationContext */
	private ThemeSource themeSource;


	public InheritableAbstractRefreshableWebApplicationContext() {
		setDisplayName("Root WebApplicationContext");
	}
	
	public InheritableAbstractRefreshableWebApplicationContext(ApplicationContext parentCtx) {
		super(parentCtx);
		setDisplayName("Root WebApplicationContext");
	}
	
	


	public void setServletContext(ServletContext servletContext) {
		this.servletContext = servletContext;
	}

	public ServletContext getServletContext() {
		return this.servletContext;
	}

	public void setServletConfig(ServletConfig servletConfig) {
		this.servletConfig = servletConfig;
		if (servletConfig != null && this.servletContext == null) {
			setServletContext(servletConfig.getServletContext());
		}
	}

	public ServletConfig getServletConfig() {
		return this.servletConfig;
	}

	public void setNamespace(String namespace) {
		this.namespace = namespace;
		if (namespace != null) {
			setDisplayName("WebApplicationContext for namespace '" + namespace + "'");
		}
	}

	public String getNamespace() {
		return this.namespace;
	}

	@Override
	public String[] getConfigLocations() {
		return super.getConfigLocations();
	}

	@Override
	public String getApplicationName() {
		if (this.servletContext == null) {
			return "";
		}
		if (this.servletContext.getMajorVersion() == 2 && this.servletContext.getMinorVersion() < 5) {
			String name = this.servletContext.getServletContextName();
			return (name != null ? name : "");
		}
		else {
			// Servlet 2.5 available
			return this.servletContext.getContextPath();
		}
	}

	/**
	 * Create and return a new {@link StandardServletEnvironment}. Subclasses may override
	 * in order to configure the environment or specialize the environment type returned.
	 */
	@Override
	protected ConfigurableEnvironment createEnvironment() {
		return new StandardServletEnvironment();
	}

	/**
	 * Register request/session scopes, a {@link ServletContextAwareProcessor}, etc.
	 */
	@Override
	protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
		beanFactory.addBeanPostProcessor(new ServletContextAwareProcessor(this.servletContext, this.servletConfig));
		beanFactory.ignoreDependencyInterface(ServletContextAware.class);
		beanFactory.ignoreDependencyInterface(ServletConfigAware.class);

		WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext);
		WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext, this.servletConfig);
	}

	/**
	 * This implementation supports file paths beneath the root of the ServletContext.
	 * @see ServletContextResource
	 */
	@Override
	protected Resource getResourceByPath(String path) {
		return new ServletContextResource(this.servletContext, path);
	}

	/**
	 * This implementation supports pattern matching in unexpanded WARs too.
	 * @see ServletContextResourcePatternResolver
	 */
	@Override
	protected ResourcePatternResolver getResourcePatternResolver() {
		return new ServletContextResourcePatternResolver(this);
	}

	/**
	 * Initialize the theme capability.
	 */
	@Override
	protected void onRefresh() {
		this.themeSource = UiApplicationContextUtils.initThemeSource(this);
	}

	/**
	 * {@inheritDoc}
	 * <p>Replace {@code Servlet}-related property sources.
	 */
	@Override
	protected void initPropertySources() {
		super.initPropertySources();
		ConfigurableEnvironment env = this.getEnvironment();
		if (env instanceof ConfigurableWebEnvironment) {
			((ConfigurableWebEnvironment)env).initPropertySources(
					this.servletContext, this.servletConfig);
		}
	}

	public Theme getTheme(String themeName) {
		return this.themeSource.getTheme(themeName);
	}

}

InheritableAnnotationConfigWebApplicationContext.java

import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotatedBeanDefinitionReader;
import org.springframework.context.annotation.AnnotationConfigUtils;
import org.springframework.context.annotation.ClassPathBeanDefinitionScanner;
import org.springframework.context.annotation.ScopeMetadataResolver;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.support.XmlWebApplicationContext;

/**
 * {@link org.springframework.web.context.WebApplicationContext WebApplicationContext}
 * implementation which accepts annotated classes as input - in particular
 * {@link org.springframework.context.annotation.Configuration @Configuration}-annotated
 * classes, but also plain {@link org.springframework.stereotype.Component @Component}
 * classes and JSR-330 compliant classes using {@code javax.inject} annotations. Allows
 * for registering classes one by one (specifying class names as config location) as well
 * as for classpath scanning (specifying base packages as config location).
 *
 * <p>This is essentially the equivalent of
 * {@link org.springframework.context.annotation.AnnotationConfigApplicationContext
 * AnnotationConfigApplicationContext} for a web environment.
 *
 * <p>To make use of this application context, the
 * {@linkplain ContextLoader#CONTEXT_CLASS_PARAM "contextClass"} context-param for
 * ContextLoader and/or "contextClass" init-param for FrameworkServlet must be set to
 * the fully-qualified name of this class.
 *
 * <p>As of Spring 3.1, this class may also be directly instantiated and injected into
 * Spring's {@code DispatcherServlet} or {@code ContextLoaderListener} when using the
 * new {@link org.springframework.web.WebApplicationInitializer WebApplicationInitializer}
 * code-based alternative to {@code web.xml}. See its Javadoc for details and usage examples.
 *
 * <p>Unlike {@link XmlWebApplicationContext}, no default configuration class locations
 * are assumed. Rather, it is a requirement to set the
 * {@linkplain ContextLoader#CONFIG_LOCATION_PARAM "contextConfigLocation"}
 * context-param for {@link ContextLoader} and/or "contextConfigLocation" init-param for
 * FrameworkServlet.  The param-value may contain both fully-qualified
 * class names and base packages to scan for components. See {@link #loadBeanDefinitions}
 * for exact details on how these locations are processed.
 *
 * <p>As an alternative to setting the "contextConfigLocation" parameter, users may
 * implement an {@link org.springframework.context.ApplicationContextInitializer
 * ApplicationContextInitializer} and set the
 * {@linkplain ContextLoader#CONTEXT_INITIALIZER_CLASSES_PARAM "contextInitializerClasses"}
 * context-param / init-param. In such cases, users should favor the {@link #refresh()}
 * and {@link #scan(String...)} methods over the {@link #setConfigLocation(String)}
 * method, which is primarily for use by {@code ContextLoader}
 *
 * <p>Note: In case of multiple {@code @Configuration} classes, later {@code @Bean}
 * definitions will override ones defined in earlier loaded files. This can be leveraged
 * to deliberately override certain bean definitions via an extra Configuration class.
 *
 * @author Chris Beams
 * @author Juergen Hoeller
 * @since 3.0
 * @see org.springframework.context.annotation.AnnotationConfigApplicationContext
 */
public class InheritableAnnotationConfigWebApplicationContext extends InheritableAbstractRefreshableWebApplicationContext {

  private Class<?>[] annotatedClasses;

	private String[] basePackages;

	private BeanNameGenerator beanNameGenerator;

	private ScopeMetadataResolver scopeMetadataResolver;
	
	public InheritableAnnotationConfigWebApplicationContext() {
		super();
	}
	
	public InheritableAnnotationConfigWebApplicationContext(ApplicationContext parent) {
		super(parent);
	}
	

	/**
	 * {@inheritDoc}
	 * <p>This implementation accepts delimited values in the form of fully-qualified
	 * class names, (typically of {@code Configuration} classes) or fully-qualified
	 * packages to scan for annotated classes. During {@link #loadBeanDefinitions}, these
	 * locations will be processed in their given order, first attempting to load each
	 * value as a class. If class loading fails (i.e. a {@code ClassNotFoundException}
	 * occurs), the value is assumed to be a package and scanning is attempted.
	 * <p>Note that this method exists primarily for compatibility with Spring's
	 * {@link org.springframework.web.context.ContextLoader} and that if this application
	 * context is being configured through an
	 * {@link org.springframework.context.ApplicationContextInitializer}, use of the
	 * {@link #register} and {@link #scan} methods are preferred.
	 * @see #register(Class...)
	 * @see #scan(String...)
	 * @see #setConfigLocations(String[])
	 * @see #loadBeanDefinitions(DefaultListableBeanFactory)
	 */
	@Override
	public void setConfigLocation(String location) {
		super.setConfigLocation(location);
	}

	/**
	 * {@inheritDoc}
	 * <p>This implementation accepts individual location values as fully-qualified class
	 * names (typically {@code @Configuration} classes) or fully-qualified packages to
	 * scan. During {@link #loadBeanDefinitions}, these locations will be processed in
	 * order, first attempting to load values as a class, and upon class loading failure
	 * the value is assumed to be a package to be scanned.
	 * <p>Note that this method exists primarily for compatibility with Spring's
	 * {@link org.springframework.web.context.ContextLoader} and that if this application
	 * context is being configured through an
	 * {@link org.springframework.context.ApplicationContextInitializer}, use of the
	 * {@link #register} and {@link #scan} methods are preferred.
	 * @see #scan(String...)
	 * @see #register(Class...)
	 * @see #setConfigLocation(String)
	 * @see #loadBeanDefinitions(DefaultListableBeanFactory)
	 */
	@Override
	public void setConfigLocations(String[] locations) {
		super.setConfigLocations(locations);
	}

	/**
	 * Register one or more annotated classes to be processed.
	 * Note that {@link #refresh()} must be called in order for the context to fully
	 * process the new class.
	 * <p>Calls to {@link #register} are idempotent; adding the same
	 * annotated class more than once has no additional effect.
	 * @param annotatedClasses one or more annotated classes,
	 * e.g. {@link org.springframework.context.annotation.Configuration @Configuration} classes
	 * @see #scan(String...)
	 * @see #loadBeanDefinitions(DefaultListableBeanFactory)
	 * @see #setConfigLocation(String)
	 * @see #refresh()
	 */
	public void register(Class<?>... annotatedClasses) {
		Assert.notEmpty(annotatedClasses, "At least one annotated class must be specified");
		this.annotatedClasses = annotatedClasses;
	}

	/**
	 * Perform a scan within the specified base packages.
	 * Note that {@link #refresh()} must be called in order for the context to
	 * fully process the new class.
	 * @param basePackages the packages to check for annotated classes
	 * @see #loadBeanDefinitions(DefaultListableBeanFactory)
	 * @see #register(Class...)
	 * @see #setConfigLocation(String)
	 * @see #refresh()
	 */
	public void scan(String... basePackages) {
		Assert.notEmpty(basePackages, "At least one base package must be specified");
		this.basePackages = basePackages;
	}

	/**
	 * Register a {@link org.springframework.beans.factory.config.BeanDefinition} for
	 * any classes specified by {@link #register(Class...)} and scan any packages
	 * specified by {@link #scan(String...)}.
	 * <p>For any values specified by {@link #setConfigLocation(String)} or
	 * {@link #setConfigLocations(String[])}, attempt first to load each location as a
	 * class, registering a {@code BeanDefinition} if class loading is successful,
	 * and if class loading fails (i.e. a {@code ClassNotFoundException} is raised),
	 * assume the value is a package and attempt to scan it for annotated classes.
	 * <p>Enables the default set of annotation configuration post processors, such that
	 * {@code @Autowired}, {@code @Required}, and associated annotations can be used.
	 * <p>Configuration class bean definitions are registered with generated bean
	 * definition names unless the {@code value} attribute is provided to the stereotype
	 * annotation.
	 * @see #register(Class...)
	 * @see #scan(String...)
	 * @see #setConfigLocation(String)
	 * @see #setConfigLocations(String[])
	 * @see AnnotatedBeanDefinitionReader
	 * @see ClassPathBeanDefinitionScanner
	 */
	@Override
	protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) {
		AnnotatedBeanDefinitionReader reader = new AnnotatedBeanDefinitionReader(beanFactory);
		reader.setEnvironment(this.getEnvironment());

		ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(beanFactory);
		scanner.setEnvironment(this.getEnvironment());

		BeanNameGenerator beanNameGenerator = getBeanNameGenerator();
		ScopeMetadataResolver scopeMetadataResolver = getScopeMetadataResolver();
		if (beanNameGenerator != null) {
			reader.setBeanNameGenerator(beanNameGenerator);
			scanner.setBeanNameGenerator(beanNameGenerator);
			beanFactory.registerSingleton(
					AnnotationConfigUtils.CONFIGURATION_BEAN_NAME_GENERATOR, beanNameGenerator);
		}
		if (scopeMetadataResolver != null) {
			reader.setScopeMetadataResolver(scopeMetadataResolver);
			scanner.setScopeMetadataResolver(scopeMetadataResolver);
		}

		if (!ObjectUtils.isEmpty(this.annotatedClasses)) {
			if (logger.isInfoEnabled()) {
				logger.info("Registering annotated classes: [" +
						StringUtils.arrayToCommaDelimitedString(this.annotatedClasses) + "]");
			}
			reader.register(this.annotatedClasses);
		}

		if (!ObjectUtils.isEmpty(this.basePackages)) {
			if (logger.isInfoEnabled()) {
				logger.info("Scanning base packages: [" +
						StringUtils.arrayToCommaDelimitedString(this.basePackages) + "]");
			}
			scanner.scan(this.basePackages);
		}

		String[] configLocations = getConfigLocations();
		if (configLocations != null) {
			for (String configLocation : configLocations) {
				try {
					Class<?> clazz = getClassLoader().loadClass(configLocation);
					if (logger.isInfoEnabled()) {
						logger.info("Successfully resolved class for [" + configLocation + "]");
					}
					reader.register(clazz);
				}
				catch (ClassNotFoundException ex) {
					if (logger.isDebugEnabled()) {
						logger.debug("Could not load class for config location [" + configLocation +
								"] - trying package scan. " + ex);
					}
					int count = scanner.scan(configLocation);
					if (logger.isInfoEnabled()) {
						if (count == 0) {
							logger.info("No annotated classes found for specified class/package [" + configLocation + "]");
						}
						else {
							logger.info("Found " + count + " annotated classes in package [" + configLocation + "]");
						}
					}
				}
			}
		}
	}

	public void setBeanNameGenerator(BeanNameGenerator beanNameGenerator) {
		this.beanNameGenerator = beanNameGenerator;
	}

	/**
	 * Provide a custom {@link BeanNameGenerator} for use with {@link AnnotatedBeanDefinitionReader}
	 * and/or {@link ClassPathBeanDefinitionScanner}, if any.
	 * <p>Default is {@link org.springframework.context.annotation.AnnotationBeanNameGenerator}.
	 * @see AnnotatedBeanDefinitionReader#setBeanNameGenerator
	 * @see ClassPathBeanDefinitionScanner#setBeanNameGenerator
	 */
	protected BeanNameGenerator getBeanNameGenerator() {
		return this.beanNameGenerator;
	}

	/**
	 * Set the {@link ScopeMetadataResolver} to use for detected bean classes.
	 * <p>The default is an {@link org.springframework.context.annotation.AnnotationScopeMetadataResolver}.
	 */
	public void setScopeMetadataResolver(ScopeMetadataResolver scopeMetadataResolver) {
		this.scopeMetadataResolver = scopeMetadataResolver;
	}

	/**
	 * Provide a custom {@link ScopeMetadataResolver} for use with {@link AnnotatedBeanDefinitionReader}
	 * and/or {@link ClassPathBeanDefinitionScanner}, if any.
	 * <p>Default is {@link org.springframework.context.annotation.AnnotationScopeMetadataResolver}.
	 * @see AnnotatedBeanDefinitionReader#setScopeMetadataResolver
	 * @see ClassPathBeanDefinitionScanner#setScopeMetadataResolver
	 */
	protected ScopeMetadataResolver getScopeMetadataResolver() {
		return this.scopeMetadataResolver;
	}
}