M1 cut of environment, profiles and property work (SPR-7508)

Decomposed Environment interface into PropertySources, PropertyResolver
objects

    Environment interface and implementations are still present, but
    simpler.

    PropertySources container aggregates PropertySource objects;
    PropertyResolver provides search, conversion, placeholder
    replacement. Single implementation for now is
    PropertySourcesPlaceholderResolver

Renamed EnvironmentAwarePropertyPlaceholderConfigurer to
PropertySourcesPlaceholderConfigurer

    <context:property-placeholder/> now registers PSPC by default, else
    PPC if systemPropertiesMode* settings are involved

Refined configuration and behavior of default profiles

    See Environment interface Javadoc for details

Added Portlet implementations of relevant interfaces:

    * DefaultPortletEnvironment
    * PortletConfigPropertySource, PortletContextPropertySource
    * Integrated each appropriately throughout Portlet app contexts

Added protected 'createEnvironment()' method to AbstractApplicationContext

    Subclasses can override at will to supply a custom Environment
    implementation.  In practice throughout the framework, this is how
    Web- and Portlet-related ApplicationContexts override use of the
    DefaultEnvironment and swap in DefaultWebEnvironment or
    DefaultPortletEnvironment as appropriate.

Introduced "stub-and-replace" behavior for Servlet- and Portlet-based
PropertySource implementations

    Allows for early registration and ordering of the stub, then
    replacement with actual backing object at refresh() time.

    Added AbstractApplicationContext.initPropertySources() method to
    support stub-and-replace behavior. Called from within existing
    prepareRefresh() method so as to avoid impact with
    ApplicationContext implementations that copy and modify AAC's
    refresh() method (e.g.: Spring DM).

    Added methods to WebApplicationContextUtils and
    PortletApplicationContextUtils to support stub-and-replace behavior

Added comprehensive Javadoc for all new or modified types and members

Added XSD documentation for all new or modified elements and attributes

    Including nested <beans>, <beans profile="..."/>, and changes for
    certain attributes type from xsd:IDREF to xsd:string

Improved fix for detecting non-file based Resources in
PropertiesLoaderSupport (SPR-7547, SPR-7552)

    Technically unrelated to environment work, but grouped in with
    this changeset for convenience.

Deprecated (removed) context:property-placeholder
'system-properties-mode' attribute from spring-context-3.1.xsd

    Functionality is preserved for those using schemas up to and including
    spring-context-3.0.  For 3.1, system-properties-mode is no longer
    supported as it conflicts with the idea of managing a set of property
    sources within the context's Environment object. See Javadoc in
    PropertyPlaceholderConfigurer, AbstractPropertyPlaceholderConfigurer
    and PropertySourcesPlaceholderConfigurer for details.

Introduced CollectionUtils.toArray(Enumeration<E>, A[])

Work items remaining for 3.1 M2:

    Consider repackaging PropertySource* types; eliminate internal use
    of SystemPropertyUtils and deprecate

    Further work on composition of Environment interface; consider
    repurposing existing PlaceholderResolver interface to obviate need
    for resolve[Required]Placeholder() methods currently in Environment.

    Ensure configurability of placeholder prefix, suffix, and value
    separator when working against an AbstractPropertyResolver

    Add JNDI-based Environment / PropertySource implementatinos

    Consider support for @Profile at the @Bean level

    Provide consistent logging for the entire property resolution
    lifecycle; consider issuing all such messages against a dedicated
    logger with a single category.

    Add reference documentation to cover the featureset.

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/HttpServletBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2008 the original author or authors.
+ * Copyright 2002-2011 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.
@@ -35,12 +35,12 @@ import org.springframework.beans.PropertyAccessorFactory;
 import org.springframework.beans.PropertyValue;
 import org.springframework.beans.PropertyValues;
 import org.springframework.context.EnvironmentAware;
-import org.springframework.core.env.DefaultWebEnvironment;
 import org.springframework.core.env.Environment;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceEditor;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.util.StringUtils;
+import org.springframework.web.context.support.DefaultWebEnvironment;
 import org.springframework.web.context.support.ServletContextResourceLoader;
 
 /**
@@ -75,7 +75,8 @@ import org.springframework.web.context.support.ServletContextResourceLoader;
  * @see #doGet
  * @see #doPost
  */
-public abstract class HttpServletBean extends HttpServlet {
+@SuppressWarnings("serial")
+public abstract class HttpServletBean extends HttpServlet implements EnvironmentAware {
 
 	/** Logger available to subclasses */
 	protected final Log logger = LogFactory.getLog(getClass());
@@ -86,9 +87,6 @@ public abstract class HttpServletBean extends HttpServlet {
 	 */
 	private final Set<String> requiredProperties = new HashSet<String>();
 
-	/**
-	 * TODO SPR-7508: think about making this overridable {@link EnvironmentAware}?
-	 */
 	private Environment environment = new DefaultWebEnvironment();
 
 
@@ -182,6 +180,15 @@ public abstract class HttpServletBean extends HttpServlet {
 	protected void initServletBean() throws ServletException {
 	}
 
+	/**
+	 * {@inheritDoc}
+	 * <p>Any environment set here overrides the {@link DefaultWebEnvironment}
+	 * provided by default.
+	 */
+	public void setEnvironment(Environment environment) {
+		this.environment = environment;
+	}
+
 
 	/**
 	 * PropertyValues implementation created from ServletConfig init parameters.

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java

@@ -35,9 +35,9 @@ import org.springframework.web.servlet.support.WebContentGenerator;
 /**
  * {@link HttpRequestHandler} that serves static resources optimized for superior browser performance 
  * (according to the guidelines of Page Speed, YSlow, etc.) by allowing for flexible cache settings
- * ({@link #setCacheSeconds "cacheSeconds" property}, last-modified support).
+ * ({@linkplain #setCacheSeconds "cacheSeconds" property}, last-modified support).
  *
- * <p>The {@link #setLocations "locations" property takes a list of Spring {@link Resource} locations
+ * <p>The {@linkplain #setLocations "locations" property} takes a list of Spring {@link Resource} locations
  * from which static resources are allowed  to be served by this handler. For a given request, the
  * list of locations will be consulted in order for the presence of the requested resource, and the
  * first found match will be written to the response, with {@code Expires} and {@code Cache-Control}
@@ -54,7 +54,7 @@ import org.springframework.web.servlet.support.WebContentGenerator;
  * using Spring EL. See the reference manual for further examples of this approach.
  *
  * <p>Rather than being directly configured as a bean, this handler will typically be configured
- * through use of the <code>&lt;mvc:resources/&gt;</code> XML configuration element.
+ * through use of the {@code <mvc:resources/>} XML configuration element.
  *
  * @author Keith Donald
  * @author Jeremy Grelle