AbstractApplicationContext registers default embedded value resolver

Issue: SPR-14140

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/factory/config/ConfigurableBeanFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -209,6 +209,13 @@ public interface ConfigurableBeanFactory extends HierarchicalBeanFactory, Single
 	 */
 	void addEmbeddedValueResolver(StringValueResolver valueResolver);
 
+	/**
+	 * Determine whether an embedded value resolver has been registered with this
+	 * bean factory, to be applied through {@link #resolveEmbeddedValue(String)}.
+	 * @since 4.3
+	 */
+	boolean hasEmbeddedValueResolver();
+
 	/**
 	 * Resolve the given embedded value, e.g. an annotation attribute.
 	 * @param value the value to resolve

spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -798,6 +798,11 @@ public void addEmbeddedValueResolver(StringValueResolver valueResolver) {
 		this.embeddedValueResolvers.add(valueResolver);
 	}
 
+	@Override
+	public boolean hasEmbeddedValueResolver() {
+		return !this.embeddedValueResolvers.isEmpty();
+	}
+
 	@Override
 	public String resolveEmbeddedValue(String value) {
 		String result = value;

spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java

@@ -78,6 +78,7 @@
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.ReflectionUtils;
+import org.springframework.util.StringValueResolver;
 
 /**
  * Abstract implementation of the {@link org.springframework.context.ApplicationContext}
@@ -825,6 +826,18 @@ protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory b
 					beanFactory.getBean(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class));
 		}
 
+		// Register a default embedded value resolver if no bean post-processor
+		// (such as a PropertyPlaceholderConfigurer bean) registered any before:
+		// at this point, primarily for resolution in annotation attribute values.
+		if (!beanFactory.hasEmbeddedValueResolver()) {
+			beanFactory.addEmbeddedValueResolver(new StringValueResolver() {
+				@Override
+				public String resolveStringValue(String strVal) {
+					return getEnvironment().resolvePlaceholders(strVal);
+				}
+			});
+		}
+
 		// Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early.
 		String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);
 		for (String weaverAwareName : weaverAwareNames) {

spring-web/src/test/java/org/springframework/web/method/annotation/RequestHeaderMethodArgumentResolverTests.java

@@ -51,7 +51,8 @@ public class RequestHeaderMethodArgumentResolverTests {
 	private MethodParameter paramNamedValueStringArray;
 	private MethodParameter paramSystemProperty;
 	private MethodParameter paramContextPath;
-	private MethodParameter paramResolvedName;
+	private MethodParameter paramResolvedNameWithExpression;
+	private MethodParameter paramResolvedNameWithPlaceholder;
 	private MethodParameter paramNamedValueMap;
 
 	private MockHttpServletRequest servletRequest;
@@ -71,8 +72,9 @@ public void setUp() throws Exception {
 		paramNamedValueStringArray = new SynthesizingMethodParameter(method, 1);
 		paramSystemProperty = new SynthesizingMethodParameter(method, 2);
 		paramContextPath = new SynthesizingMethodParameter(method, 3);
-		paramResolvedName = new SynthesizingMethodParameter(method, 4);
-		paramNamedValueMap = new SynthesizingMethodParameter(method, 5);
+		paramResolvedNameWithExpression = new SynthesizingMethodParameter(method, 4);
+		paramResolvedNameWithPlaceholder = new SynthesizingMethodParameter(method, 5);
+		paramNamedValueMap = new SynthesizingMethodParameter(method, 6);
 
 		servletRequest = new MockHttpServletRequest();
 		webRequest = new ServletWebRequest(servletRequest, new MockHttpServletResponse());
@@ -135,13 +137,29 @@ public void resolveDefaultValueFromSystemProperty() throws Exception {
 	}
 
 	@Test
-	public void resolveNameFromSystemProperty() throws Exception {
+	public void resolveNameFromSystemPropertyThroughExpression() throws Exception {
 		String expected = "foo";
 		servletRequest.addHeader("bar", expected);
 
 		System.setProperty("systemProperty", "bar");
 		try {
-			Object result = resolver.resolveArgument(paramResolvedName, null, webRequest, null);
+			Object result = resolver.resolveArgument(paramResolvedNameWithExpression, null, webRequest, null);
+			assertTrue(result instanceof String);
+			assertEquals("Invalid result", expected, result);
+		}
+		finally {
+			System.clearProperty("systemProperty");
+		}
+	}
+
+	@Test
+	public void resolveNameFromSystemPropertyThroughPlaceholder() throws Exception {
+		String expected = "foo";
+		servletRequest.addHeader("bar", expected);
+
+		System.setProperty("systemProperty", "bar");
+		try {
+			Object result = resolver.resolveArgument(paramResolvedNameWithPlaceholder, null, webRequest, null);
 			assertTrue(result instanceof String);
 			assertEquals("Invalid result", expected, result);
 		}
@@ -171,6 +189,7 @@ public void params(
 			@RequestHeader(name = "name", defaultValue="#{systemProperties.systemProperty}") String param3,
 			@RequestHeader(name = "name", defaultValue="#{request.contextPath}") String param4,
 			@RequestHeader("#{systemProperties.systemProperty}") String param5,
+			@RequestHeader("${systemProperty}") String param6,
 			@RequestHeader("name") Map<?, ?> unsupported) {
 	}