Check template availability in ScriptTemplateView

This commit overrides the `checkResource` implementation in
`ScriptTemplateView` in order to check if the template file resource is
available and if the resolver can then proceed with rendering the
template.

Issue: SPR-14729
Cherry-picked from: 66b370e

Author: bclozel

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

@@ -16,12 +16,14 @@
 
 package org.springframework.web.servlet.view.script;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import javax.script.Invocable;
 import javax.script.ScriptEngine;
@@ -192,6 +194,19 @@ public void setResourceLoaderPath(String resourceLoaderPath) {
 		}
 	}
 
+	@Override
+	public boolean checkResource(Locale locale) throws Exception {
+		try {
+			getTemplate(getUrl());
+			return true;
+		}
+		catch (IllegalStateException exc) {
+			if (logger.isDebugEnabled()) {
+				logger.debug("No ScriptTemplate view found for URL: " + getUrl());
+			}
+			return false;
+		}
+	}
 
 	@Override
 	protected void initApplicationContext(ApplicationContext context) {

spring-webmvc/src/test/java/org/springframework/web/servlet/view/script/ScriptTemplateViewTests.java

@@ -20,6 +20,7 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -28,7 +29,9 @@
 import javax.script.ScriptEngine;
 
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 
 import org.springframework.beans.DirectFieldAccessor;
 import org.springframework.context.ApplicationContextException;
@@ -58,6 +61,8 @@ public class ScriptTemplateViewTests {
 
 	private StaticWebApplicationContext wac;
 
+	@Rule
+	public ExpectedException expectedException = ExpectedException.none();
 
 	@Before
 	public void setup() {
@@ -68,15 +73,24 @@ public void setup() {
 	}
 
 
+	@Test
+	public void missingTemplate() throws Exception {
+		MockServletContext servletContext = new MockServletContext();
+		this.wac.setServletContext(servletContext);
+		this.wac.refresh();
+		this.view.setResourceLoaderPath("classpath:org/springframework/web/servlet/view/script/");
+		this.view.setUrl("missing.txt");
+		this.view.setEngine(mock(InvocableScriptEngine.class));
+		this.configurer.setRenderFunction("render");
+		this.view.setApplicationContext(this.wac);
+		assertFalse(this.view.checkResource(Locale.ENGLISH));
+	}
+
 	@Test
 	public void missingScriptTemplateConfig() throws Exception {
-		try {
-			this.view.setApplicationContext(new StaticApplicationContext());
-			fail("Should have thrown ApplicationContextException");
-		}
-		catch (ApplicationContextException ex) {
-			assertTrue(ex.getMessage().contains("ScriptTemplateConfig"));
-		}
+		this.expectedException.expect(ApplicationContextException.class);
+		this.view.setApplicationContext(new StaticApplicationContext());
+		this.expectedException.expectMessage(contains("ScriptTemplateConfig"));
 	}
 
 	@Test
@@ -152,53 +166,37 @@ public void nonSharedEngine() throws Exception {
 
 	@Test
 	public void nonInvocableScriptEngine() throws Exception {
-		try {
-			this.view.setEngine(mock(ScriptEngine.class));
-			fail("Should have thrown IllegalArgumentException");
-		}
-		catch (IllegalArgumentException ex) {
-			assertThat(ex.getMessage(), containsString("instance"));
-		}
+		this.expectedException.expect(IllegalArgumentException.class);
+		this.view.setEngine(mock(ScriptEngine.class));
+		this.expectedException.expectMessage(contains("instance"));
 	}
 
 	@Test
 	public void noRenderFunctionDefined() {
 		this.view.setEngine(mock(InvocableScriptEngine.class));
-		try {
-			this.view.setApplicationContext(this.wac);
-			fail("Should have thrown IllegalArgumentException");
-		}
-		catch (IllegalArgumentException ex) {
-			assertThat(ex.getMessage(), containsString("renderFunction"));
-		}
+		this.expectedException.expect(IllegalArgumentException.class);
+		this.view.setApplicationContext(this.wac);
+		this.expectedException.expectMessage(contains("renderFunction"));
 	}
 
 	@Test
 	public void engineAndEngineNameBothDefined() {
 		this.view.setEngine(mock(InvocableScriptEngine.class));
 		this.view.setEngineName("test");
 		this.view.setRenderFunction("render");
-		try {
-			this.view.setApplicationContext(this.wac);
-			fail("Should have thrown IllegalArgumentException");
-		}
-		catch (IllegalArgumentException ex) {
-			assertThat(ex.getMessage(), containsString("'engine' or 'engineName'"));
-		}
+		this.expectedException.expect(IllegalArgumentException.class);
+		this.view.setApplicationContext(this.wac);
+		this.expectedException.expectMessage(contains("'engine' or 'engineName'"));
 	}
 
 	@Test
 	public void engineSetterAndNonSharedEngine() {
 		this.view.setEngine(mock(InvocableScriptEngine.class));
 		this.view.setRenderFunction("render");
 		this.view.setSharedEngine(false);
-		try {
-			this.view.setApplicationContext(this.wac);
-			fail("Should have thrown IllegalArgumentException");
-		}
-		catch (IllegalArgumentException ex) {
-			assertThat(ex.getMessage(), containsString("sharedEngine"));
-		}
+		this.expectedException.expect(IllegalArgumentException.class);
+		this.view.setApplicationContext(this.wac);
+		this.expectedException.expectMessage(contains("sharedEngine"));
 	}
 
 	@Test // SPR-14210