Add support for placeholders in @RequestMapping

@RequestMapping annotations now support ${...} placeholders.

Issue: SPR-9935

spring-web/src/main/java/org/springframework/web/bind/annotation/RequestMapping.java

@@ -266,6 +266,7 @@
 	 * Ant-style path patterns are also supported (e.g. "/myPath/*.do").
 	 * At the method level, relative paths (e.g. "edit.do") are supported
 	 * within the primary mapping expressed at the type level.
+	 * Path mapping URIs may contain placeholders (e.g. "/${connect}")
 	 * <p>In a Portlet environment: the mapped portlet modes
 	 * (i.e. "EDIT", "VIEW", "HELP" or any custom modes).
 	 * <p><b>Supported at the type level as well as at the method level!</b>

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -20,9 +20,11 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import org.springframework.context.EmbeddedValueResolverAware;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.stereotype.Controller;
 import org.springframework.util.Assert;
+import org.springframework.util.StringValueResolver;
 import org.springframework.web.accept.ContentNegotiationManager;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.servlet.mvc.condition.AbstractRequestCondition;
@@ -46,7 +48,8 @@
  * @author Rossen Stoyanchev
  * @since 3.1
  */
-public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMapping {
+public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMapping
+		implements EmbeddedValueResolverAware {
 
 	private boolean useSuffixPatternMatch = true;
 
@@ -58,6 +61,8 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 
 	private final List<String> fileExtensions = new ArrayList<String>();
 
+	private StringValueResolver embeddedValueResolver;
+
 
 	/**
 	 * Whether to use suffix pattern match (".*") when matching patterns to
@@ -101,6 +106,11 @@ public void setUseTrailingSlashMatch(boolean useTrailingSlashMatch) {
 		this.useTrailingSlashMatch = useTrailingSlashMatch;
 	}
 
+	@Override
+	public void setEmbeddedValueResolver(StringValueResolver resolver) {
+		this.embeddedValueResolver  = resolver;
+	}
+
 	/**
 	 * Set the {@link ContentNegotiationManager} to use to determine requested media types.
 	 * If not set, the default constructor is used.
@@ -142,7 +152,7 @@ public ContentNegotiationManager getContentNegotiationManager() {
 	 * Return the file extensions to use for suffix pattern matching.
 	 */
 	public List<String> getFileExtensions() {
-		return fileExtensions;
+		return this.fileExtensions;
 	}
 
 	@Override
@@ -227,8 +237,9 @@ protected RequestCondition<?> getCustomMethodCondition(Method method) {
 	 * Created a RequestMappingInfo from a RequestMapping annotation.
 	 */
 	private RequestMappingInfo createRequestMappingInfo(RequestMapping annotation, RequestCondition<?> customCondition) {
+		String[] patterns = resolveEmbeddedValuesInPatterns(annotation.value());
 		return new RequestMappingInfo(
-				new PatternsRequestCondition(annotation.value(), getUrlPathHelper(), getPathMatcher(),
+				new PatternsRequestCondition(patterns, getUrlPathHelper(), getPathMatcher(),
 						this.useSuffixPatternMatch, this.useTrailingSlashMatch, this.fileExtensions),
 				new RequestMethodsRequestCondition(annotation.method()),
 				new ParamsRequestCondition(annotation.params()),
@@ -238,4 +249,21 @@ private RequestMappingInfo createRequestMappingInfo(RequestMapping annotation, R
 				customCondition);
 	}
 
+	/**
+	 * Resolve placeholder values in the given array of patterns.
+	 * @return a new array with updated patterns
+	 */
+	protected String[] resolveEmbeddedValuesInPatterns(String[] patterns) {
+		if (this.embeddedValueResolver == null) {
+			return patterns;
+		}
+		else {
+			String[] resolvedPatterns = new String[patterns.length];
+			for (int i=0; i < patterns.length; i++) {
+				resolvedPatterns[i] = this.embeddedValueResolver.resolveStringValue(patterns[i]);
+			}
+			return resolvedPatterns;
+		}
+	}
+
 }

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMappingTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -24,6 +24,7 @@
 import org.junit.Before;
 import org.junit.Test;
 import org.springframework.http.MediaType;
+import org.springframework.util.StringValueResolver;
 import org.springframework.web.accept.ContentNegotiationManager;
 import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
 import org.springframework.web.context.support.StaticWebApplicationContext;
@@ -78,4 +79,18 @@ public void useSuffixPatternMatch() {
 				this.handlerMapping.useSuffixPatternMatch());
 	}
 
+	@Test
+	public void resolveEmbeddedValuesInPatterns() {
+		this.handlerMapping.setEmbeddedValueResolver(new StringValueResolver() {
+			public String resolveStringValue(String value) {
+				return "/${pattern}/bar".equals(value) ? "/foo/bar" : value;
+			}
+		});
+
+		String[] patterns = new String[] { "/foo", "/${pattern}/bar" };
+		String[] result = this.handlerMapping.resolveEmbeddedValuesInPatterns(patterns);
+
+		assertArrayEquals(new String[] { "/foo", "/foo/bar" }, result);
+	}
+
 }

src/reference/docbook/mvc.xml

@@ -1073,6 +1073,18 @@ public class RelativePathUriTemplateController {
         <filename>/owners/*/pets/{petId}</filename>).</para>
       </section>
 
+      <section xml:id="mvc-ann-requestmapping-placeholders">
+        <title>Patterns with Placeholders</title>
+
+        <para>Patterns in <interfacename>@RequestMapping</interfacename> annotations
+        support ${...} placeholders against local properties and/or system properties
+        and environment variables. This may be useful in cases where the path a
+        controller is mapped to may need to be customized through configuration.
+        For more information on placeholders see the Javadoc for
+        <classname>PropertyPlaceholderConfigurer</classname>.</para>
+
+      </section>
+
       <section xml:id="mvc-ann-matrix-variables">
         <title>Matrix Variables</title>