Revisit Assert to avoid single-arg assert methods (with refined messages)

Issue: SPR-15196
(cherry picked from commit 1b2dc36)

spring-web/src/main/java/org/springframework/http/client/SimpleClientHttpRequestFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -177,7 +177,9 @@ public class SimpleClientHttpRequestFactory implements ClientHttpRequestFactory,
 	 */
 	protected HttpURLConnection openConnection(URL url, Proxy proxy) throws IOException {
 		URLConnection urlConnection = (proxy != null ? url.openConnection(proxy) : url.openConnection());
-		Assert.isInstanceOf(HttpURLConnection.class, urlConnection);
+		if (!HttpURLConnection.class.isInstance(urlConnection)) {
+			throw new IllegalStateException("HttpURLConnection required for [" + url + "] but got: " + urlConnection);
+		}
 		return (HttpURLConnection) urlConnection;
 	}
 

spring-web/src/main/java/org/springframework/http/converter/xml/MappingJackson2XmlHttpMessageConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -60,16 +60,17 @@ public class MappingJackson2XmlHttpMessageConverter extends AbstractJackson2Http
 		super(objectMapper, new MediaType("application", "xml"),
 				new MediaType("text", "xml"),
 				new MediaType("application", "*+xml"));
-		Assert.isAssignable(XmlMapper.class, objectMapper.getClass());
+		Assert.isInstanceOf(XmlMapper.class, objectMapper, "XmlMapper required");
 	}
 
+
 	/**
 	 * {@inheritDoc}
-	 * The {@code objectMapper} parameter must be a {@link XmlMapper} instance.
+	 * The {@code ObjectMapper} parameter must be a {@link XmlMapper} instance.
 	 */
 	@Override
 	public void setObjectMapper(ObjectMapper objectMapper) {
-		Assert.isAssignable(XmlMapper.class, objectMapper.getClass());
+		Assert.isInstanceOf(XmlMapper.class, objectMapper, "XmlMapper required");
 		super.setObjectMapper(objectMapper);
 	}
 

spring-web/src/main/java/org/springframework/http/server/ServletServerHttpRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -180,7 +180,9 @@ public class ServletServerHttpRequest implements ServerHttpRequest {
 	@Override
 	public ServerHttpAsyncRequestControl getAsyncRequestControl(ServerHttpResponse response) {
 		if (this.asyncRequestControl == null) {
-			Assert.isInstanceOf(ServletServerHttpResponse.class, response);
+			if (!ServletServerHttpResponse.class.isInstance(response)) {
+				throw new IllegalArgumentException("Response must be a ServletServerHttpResponse: " + response.getClass());
+			}
 			ServletServerHttpResponse servletServerResponse = (ServletServerHttpResponse) response;
 			this.asyncRequestControl = new ServletServerHttpAsyncRequestControl(this, servletServerResponse);
 		}

spring-web/src/main/java/org/springframework/web/accept/PathExtensionContentNegotiationStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -140,15 +140,15 @@ public class PathExtensionContentNegotiationStrategy extends AbstractMappingCont
 
 	/**
 	 * A public method exposing the knowledge of the path extension strategy to
-	 * resolve file extensions to a MediaType in this case for a given
+	 * resolve file extensions to a {@link MediaType} in this case for a given
 	 * {@link Resource}. The method first looks up any explicitly registered
 	 * file extensions first and then falls back on JAF if available.
 	 * @param resource the resource to look up
-	 * @return the MediaType for the extension or {@code null}.
+	 * @return the MediaType for the extension, or {@code null} if none found
 	 * @since 4.3
 	 */
 	public MediaType getMediaTypeForResource(Resource resource) {
-		Assert.notNull(resource);
+		Assert.notNull(resource, "Resource must not be null");
 		MediaType mediaType = null;
 		String filename = resource.getFilename();
 		String extension = StringUtils.getFilenameExtension(filename);

spring-web/src/main/java/org/springframework/web/bind/UnsatisfiedServletRequestParameterException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * 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.
@@ -64,7 +64,7 @@ public class UnsatisfiedServletRequestParameterException extends ServletRequestB
 			Map<String, String[]> actualParams) {
 
 		super("");
-		Assert.isTrue(!CollectionUtils.isEmpty(paramConditions));
+		Assert.notEmpty(paramConditions, "Parameter conditions must not be empty");
 		this.paramConditions = paramConditions;
 		this.actualParams = actualParams;
 	}

spring-web/src/main/java/org/springframework/web/context/ContextLoader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -40,7 +40,6 @@ import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.support.PropertiesLoaderUtils;
-import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
@@ -517,7 +516,10 @@ public class ContextLoader {
 	private Class<ApplicationContextInitializer<ConfigurableApplicationContext>> loadInitializerClass(String className) {
 		try {
 			Class<?> clazz = ClassUtils.forName(className, ClassUtils.getDefaultClassLoader());
-			Assert.isAssignable(ApplicationContextInitializer.class, clazz);
+			if (!ApplicationContextInitializer.class.isAssignableFrom(clazz)) {
+				throw new ApplicationContextException(
+						"Initializer class does not implement ApplicationContextInitializer interface: " + clazz);
+			}
 			return (Class<ApplicationContextInitializer<ConfigurableApplicationContext>>) clazz;
 		}
 		catch (ClassNotFoundException ex) {

spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java

@@ -793,7 +793,7 @@ final class HierarchicalUriComponents extends UriComponents {
 		private final List<PathComponent> pathComponents;
 
 		public PathComponentComposite(List<PathComponent> pathComponents) {
-			Assert.notNull(pathComponents);
+			Assert.notNull(pathComponents, "PathComponent List must not be null");
 			this.pathComponents = pathComponents;
 		}