Support i18n and nested templates in ScriptTemplateView

This commit changes the 3rd parameter passed to the rendering
function from String url to RenderingContext renderingContext.

RenderingContext contains 4 properties:
 - ApplicationContext applicationContext
 - Locale locale
 - Function<String, String> templateLoader
 - String url

Issue: SPR-15064

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

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2002-2017 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.servlet.view.script;
+
+import java.util.Locale;
+import java.util.function.Function;
+
+import org.springframework.context.ApplicationContext;
+
+/**
+ * Context passed to {@link ScriptTemplateView} render function.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+public class RenderingContext {
+
+	private final ApplicationContext applicationContext;
+
+	private final Locale locale;
+
+	private final Function<String, String> templateLoader;
+
+	private final String url;
+
+
+	public RenderingContext(ApplicationContext applicationContext, Locale locale,
+			Function<String, String> templateLoader, String url) {
+		this.applicationContext = applicationContext;
+		this.locale = locale;
+		this.templateLoader = templateLoader;
+		this.url = url;
+	}
+
+
+	public ApplicationContext getApplicationContext() {
+		return applicationContext;
+	}
+
+	public Locale getLocale() {
+		return locale;
+	}
+
+	public Function<String, String> getTemplateLoader() {
+		return templateLoader;
+	}
+
+	public String getUrl() {
+		return url;
+	}
+
+}

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

@@ -24,6 +24,7 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
+import java.util.function.Function;
 import javax.script.Invocable;
 import javax.script.ScriptEngine;
 import javax.script.ScriptEngineManager;
@@ -83,6 +84,8 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
 
 	private String engineName;
 
+	private Locale locale;
+
 	private Boolean sharedEngine;
 
 	private String[] scripts;
@@ -126,6 +129,14 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
 		this.engine = engine;
 	}
 
+	/**
+	 * Set the {@link Locale} to pass to the render function.
+	 * @since 5.0
+	 */
+	public void setLocale(Locale locale) {
+		this.locale = locale;
+	}
+
 	/**
 	 * See {@link ScriptTemplateConfigurer#setEngineName(String)} documentation.
 	 */
@@ -345,14 +356,23 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
 			Invocable invocable = (Invocable) engine;
 			String url = getUrl();
 			String template = getTemplate(url);
+			Function<String, String> templateLoader = path -> {
+				try {
+					return getTemplate(path);
+				}
+				catch (IOException ex) {
+					throw new IllegalStateException(ex);
+				}
+			};
+			RenderingContext context = new RenderingContext(this.getApplicationContext(), this.locale, templateLoader, url);
 
 			Object html;
 			if (this.renderObject != null) {
 				Object thiz = engine.eval(this.renderObject);
-				html = invocable.invokeMethod(thiz, this.renderFunction, template, model, url);
+				html = invocable.invokeMethod(thiz, this.renderFunction, template, model, context);
 			}
 			else {
-				html = invocable.invokeFunction(this.renderFunction, template, model, url);
+				html = invocable.invokeFunction(this.renderFunction, template, model, context);
 			}
 
 			response.getWriter().write(String.valueOf(html));

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

@@ -16,6 +16,9 @@
 
 package org.springframework.web.servlet.view.script;
 
+import java.util.Locale;
+
+import org.springframework.web.servlet.View;
 import org.springframework.web.servlet.view.UrlBasedViewResolver;
 
 /**
@@ -56,6 +59,12 @@ public class ScriptTemplateViewResolver extends UrlBasedViewResolver {
 		setSuffix(suffix);
 	}
 
+	@Override
+	protected View createView(String viewName, Locale locale) throws Exception {
+		ScriptTemplateView view = (ScriptTemplateView)super.createView(viewName, locale);
+		view.setLocale(locale);
+		return view;
+	}
 
 	@Override
 	protected Class<?> requiredViewClass() {