FragmentsRendering exposes its fragments

Closes gh-35775

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

@@ -19,6 +19,7 @@ package org.springframework.web.servlet.view;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Locale;
 import java.util.Map;
 
@@ -58,7 +59,7 @@ final class DefaultFragmentsRendering implements FragmentsRendering {
 
 		this.status = status;
 		this.headers = headers;
-		this.modelAndViews = new ArrayList<>(fragments);
+		this.modelAndViews = Collections.unmodifiableCollection(new ArrayList<>(fragments));
 	}
 
 
@@ -77,6 +78,12 @@ final class DefaultFragmentsRendering implements FragmentsRendering {
 		return false;
 	}
 
+	@Override
+	public Collection<ModelAndView> fragments() {
+		return this.modelAndViews;
+	}
+
+
 	@Override
 	public void resolveNestedViews(ViewResolver resolver, Locale locale) throws Exception {
 		for (ModelAndView mv : this.modelAndViews) {

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

@@ -53,6 +53,12 @@ public interface FragmentsRendering extends SmartView {
 	 */
 	HttpHeaders headers();
 
+	/**
+	 * Return the {@code ModelAndView} for each fragment.
+	 * @since 6.2.15
+	 */
+	Collection<ModelAndView> fragments();
+
 
 	/**
 	 * Create a builder with one HTML fragment, also inheriting attributes from