Refactor SpringApplication Environment config hooks

Per discussion: fixes gh-467

spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

@@ -269,8 +269,7 @@ public class SpringApplication {
 		try {
 			// Create and configure the environment
 			ConfigurableEnvironment environment = getOrCreateEnvironment();
-			addPropertySources(environment, args);
-			setupProfiles(environment);
+			configureEnvironment(environment, args);
 			for (SpringApplicationRunListener runListener : runListeners) {
 				runListener.environmentPrepared(environment);
 			}
@@ -382,11 +381,28 @@ public class SpringApplication {
 	}
 
 	/**
-	 * Add any {@link PropertySource}s to the environment.
-	 * @param environment the environment
-	 * @param args run arguments
+	 * Template method delegating to
+	 * {@link #configurePropertySources(ConfigurableEnvironment, String[])} and
+	 * {@link #configureProfiles(ConfigurableEnvironment, String[])} in that order. Override
+	 * this method for complete control over Environment customization, or one of the above
+	 * for fine-grained control over property sources or profiles, respectively.
+	 * @param environment this application's environment
+	 * @param args arguments passed to the {@code run} method
+	 * @see #configurePropertySources(ConfigurableEnvironment, String[])
+	 * @see #configureProfiles(ConfigurableEnvironment, String[])
+	 */
+	protected void configureEnvironment(ConfigurableEnvironment environment, String[] args) {
+		configurePropertySources(environment, args);
+		configureProfiles(environment, args);
+	}
+
+	/**
+	 * Add, remove or re-order any {@link PropertySource}s in this application's environment.
+	 * @param environment this application's environment
+	 * @param args arguments passed to the {@code run} method
+	 * @see #configureEnvironment(ConfigurableEnvironment, String[])
 	 */
-	protected void addPropertySources(ConfigurableEnvironment environment, String[] args) {
+	protected void configurePropertySources(ConfigurableEnvironment environment, String[] args) {
 		MutablePropertySources sources = environment.getPropertySources();
 		if (this.defaultProperties != null && !this.defaultProperties.isEmpty()) {
 			sources.addLast(new MapPropertySource("defaultProperties",
@@ -409,10 +425,14 @@ public class SpringApplication {
 	}
 
 	/**
-	 * Setup any active profiles on the environment.
-	 * @param environment the environment to configure
+	 * Configure which profiles are active (or active by default) for this application environment.
+	 * Consider overriding this method to programmatically enforce profile rules and semantics,
+	 * such as ensuring mutual exclusivity of profiles (e.g. 'dev' OR 'prod', but never both).
+	 * @param environment this application's environment
+	 * @param args arguments passed to the {@code run} method
+	 * @see #configureEnvironment(ConfigurableEnvironment, String[])
 	 */
-	protected void setupProfiles(ConfigurableEnvironment environment) {
+	protected void configureProfiles(ConfigurableEnvironment environment, String[] args) {
 		Set<String> profiles = new LinkedHashSet<String>();
 		environment.getActiveProfiles(); // ensure they are initialized
 		// But these ones should go first (last wins in a property key clash)