Initialize FrameworkServlet property sources eagerly

Prior to this change,
FrameworkServlet#configureAndRefreshWebApplicationContext called
 #postProcessWebApplicationContext(wac) and #applyInitializers(wac)
prior to #refresh, but because servlet-based property source stubs were
not replaced until #refresh, any post-processing or initialization
routines could not benefit from accessing the Environment to retrieve
properties from the ServletContext or ServletConfig.

The workaround to this problem is detailed in SPR-9610 - the user simply
needed to call WebApplicationContextUtils#initServletPropertySources
manually within their ApplicationContextInitializer (or overridden
 #postProcessWebApplicationContext method)

This commit ensures that
FrameworkServlet#configureAndRefreshWebApplicationContext calls
WebApplicationContextUtils#initServletPropertySources eagerly, prior to
invoking #postProcessWebApplicationContext and #applyInitializers.
Related Javadoc has also been updated throughout to clarify the behavior
of #initServletPropertySources, when it can be called and what the
effects are, etc.

Note also that a reproduction issue was added to demonstrate the problem
and verify its resolution [1].

[1]: https://github.com/SpringSource/spring-framework-issues/tree/master/SPR-9610

Issue: SPR-9610

Author: cbeams

spring-web/src/main/java/org/springframework/web/context/ConfigurableWebEnvironment.java

@@ -40,6 +40,8 @@ public interface ConfigurableWebEnvironment extends ConfigurableEnvironment {
 	 * using the given parameters.
 	 * @param servletContext the {@link ServletContext} (may not be {@code null})
 	 * @param servletConfig the {@link ServletConfig} ({@code null} if not available)
+	 * @see org.springframework.web.context.support.WebApplicationContextUtils#initServletPropertySources(
+	 * org.springframework.core.env.MutablePropertySources, ServletContext, ServletConfig)
 	 */
 	void initPropertySources(ServletContext servletContext, ServletConfig servletConfig);
 

spring-web/src/main/java/org/springframework/web/context/support/WebApplicationContextUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -230,22 +230,31 @@ public static void registerEnvironmentBeans(
 	}
 
 	/**
-	 * Replace {@code Servlet}-based stub property sources with actual instances
-	 * populated with the given context object.
-	 * @see org.springframework.core.env.PropertySource.StubPropertySource
-	 * @see org.springframework.core.env.ConfigurableEnvironment#getPropertySources()
-	 * @see org.springframework.web.context.support.WebApplicationContextUtils#initServletPropertySources(MutablePropertySources, ServletContext)
+	 * Convenient variant of {@link #initServletPropertySources(MutablePropertySources,
+	 * ServletContext, ServletConfig)} that always provides {@code null} for the
+	 * {@link ServletConfig} parameter.
+	 * @see #initServletPropertySources(MutablePropertySources, ServletContext, ServletConfig)
 	 */
 	public static void initServletPropertySources(
 			MutablePropertySources propertySources, ServletContext servletContext) {
 		initServletPropertySources(propertySources, servletContext, null);
 	}
 
 	/**
-	 * Replace {@code Servlet}-based stub property sources with actual instances
-	 * populated with the given context and config objects.
+	 * Replace {@code Servlet}-based {@link StubPropertySource stub property sources} with
+	 * actual instances populated with the given {@code servletContext} and
+	 * {@code servletConfig} objects.
+	 * <p>This method is idempotent with respect to the fact it may be called any number
+	 * of times but will perform replacement of stub property sources with their
+	 * corresponding actual property sources once and only once.
+	 * @param propertySources the {@link PropertySources} to initialize (must not be {@code null})
+	 * @param servletContext the current {@link ServletContext} (ignored if {@code null}
+	 * or if the {@link StandardServletEnvironment#SERVLET_CONTEXT_PROPERTY_SOURCE_NAME
+	 * servlet context property source} has already been initialized)
+	 * @param servletConfig the current {@link ServletConfig} (ignored if {@code null}
+	 * or if the {@link StandardServletEnvironment#SERVLET_CONFIG_PROPERTY_SOURCE_NAME
+	 * servlet config property source} has already been initialized)
 	 * @see org.springframework.core.env.PropertySource.StubPropertySource
-	 * @see org.springframework.web.context.support.WebApplicationContextUtils#initServletPropertySources(MutablePropertySources, ServletContext)
 	 * @see org.springframework.core.env.ConfigurableEnvironment#getPropertySources()
 	 */
 	public static void initServletPropertySources(

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/context/PortletApplicationContextUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -188,11 +188,25 @@ static void registerEnvironmentBeans(
 	}
 
 	/**
-	 * Replace {@code Servlet}- and {@code Portlet}-based stub property sources
-	 * with actual instances populated with the given context and config objects.
+	 * Replace {@code Servlet}- and {@code Portlet}-based {@link StubPropertySource stub
+	 * property sources} with actual instances populated with the given {@code servletContext},
+	 * {@code portletContext} and {@code portletConfig} objects.
+	 * <p>This method is idempotent with respect to the fact it may be called any number
+	 * of times but will perform replacement of stub property sources with their
+	 * corresponding actual property sources once and only once.
+	 * @param propertySources the {@link PropertySources} to initialize (must not be {@code null})
+	 * @param servletContext the current {@link ServletContext} (ignored if {@code null}
+	 * or if the {@link StandardServletEnvironment#SERVLET_CONTEXT_PROPERTY_SOURCE_NAME
+	 * servlet context property source} has already been initialized)
+	 * @param portletContext the current {@link PortletContext} (ignored if {@code null}
+	 * or if the {@link StandardPortletEnvironment#PORTLET_CONTEXT_PROPERTY_SOURCE_NAME
+	 * portlet context property source} has already been initialized)
+	 * @param portletConfig the current {@link PortletConfig} (ignored if {@code null}
+	 * or if the {@link StandardPortletEnvironment#PORTLET_CONFIG_PROPERTY_SOURCE_NAME
+	 * portlet config property source} has already been initialized)
 	 * @see org.springframework.core.env.PropertySource.StubPropertySource
-	 * @see org.springframework.core.env.ConfigurableEnvironment#getPropertySources()
 	 * @see org.springframework.web.context.support.WebApplicationContextUtils#initServletPropertySources(MutablePropertySources, ServletContext)
+	 * @see org.springframework.core.env.ConfigurableEnvironment#getPropertySources()
 	 */
 	public static void initPortletPropertySources(MutablePropertySources propertySources, ServletContext servletContext,
 			PortletContext portletContext, PortletConfig portletConfig) {

spring-webmvc/src/main/java/org/springframework/web/servlet/FrameworkServlet.java

@@ -634,6 +634,12 @@ protected void configureAndRefreshWebApplicationContext(ConfigurableWebApplicati
 		wac.setNamespace(getNamespace());
 		wac.addApplicationListener(new SourceFilteringListener(wac, new ContextRefreshListener()));
 
+		// the wac environment's #initPropertySources will be called in any case when
+		// the context is refreshed; do it eagerly here to ensure servlet property sources
+		// are in place for use in any post-processing or initialization that occurs
+		// below prior to #refresh
+		wac.getEnvironment().initPropertySources(getServletContext(), getServletConfig());
+
 		postProcessWebApplicationContext(wac);
 
 		applyInitializers(wac);