Name attributes in method argument annotations allow for placeholders and expressions

Issue: SPR-13952

Author: jhoeller

spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/AbstractNamedValueMethodArgumentResolver.java

@@ -87,18 +87,24 @@ public Object resolveArgument(MethodParameter parameter, Message<?> message) thr
 		NamedValueInfo namedValueInfo = getNamedValueInfo(parameter);
 		MethodParameter nestedParameter = parameter.nestedIfOptional();
 
-		Object arg = resolveArgumentInternal(nestedParameter, message, namedValueInfo.name);
+		Object resolvedName = resolveStringValue(namedValueInfo.name);
+		if (resolvedName == null) {
+			throw new IllegalArgumentException(
+					"Specified name must not resolve to null: [" + namedValueInfo.name + "]");
+		}
+
+		Object arg = resolveArgumentInternal(nestedParameter, message, resolvedName.toString());
 		if (arg == null) {
 			if (namedValueInfo.defaultValue != null) {
-				arg = resolveDefaultValue(namedValueInfo.defaultValue);
+				arg = resolveStringValue(namedValueInfo.defaultValue);
 			}
 			else if (namedValueInfo.required && !nestedParameter.isOptional()) {
 				handleMissingValue(namedValueInfo.name, nestedParameter, message);
 			}
 			arg = handleNullValue(namedValueInfo.name, arg, nestedParameter.getNestedParameterType());
 		}
 		else if ("".equals(arg) && namedValueInfo.defaultValue != null) {
-			arg = resolveDefaultValue(namedValueInfo.defaultValue);
+			arg = resolveStringValue(namedValueInfo.defaultValue);
 		}
 
 		if (!ClassUtils.isAssignableValue(parameter.getParameterType(), arg)) {
@@ -148,6 +154,22 @@ private NamedValueInfo updateNamedValueInfo(MethodParameter parameter, NamedValu
 		return new NamedValueInfo(name, info.required, defaultValue);
 	}
 
+	/**
+	 * Resolve the given annotation-specified value,
+	 * potentially containing placeholders and expressions.
+	 */
+	private Object resolveStringValue(String value) {
+		if (this.configurableBeanFactory == null) {
+			return value;
+		}
+		String placeholdersResolved = this.configurableBeanFactory.resolveEmbeddedValue(value);
+		BeanExpressionResolver exprResolver = this.configurableBeanFactory.getBeanExpressionResolver();
+		if (exprResolver == null) {
+			return value;
+		}
+		return exprResolver.evaluate(placeholdersResolved, this.expressionContext);
+	}
+
 	/**
 	 * Resolves the given parameter type and value name into an argument value.
 	 * @param parameter the method parameter to resolve to an argument value
@@ -159,21 +181,6 @@ private NamedValueInfo updateNamedValueInfo(MethodParameter parameter, NamedValu
 	protected abstract Object resolveArgumentInternal(MethodParameter parameter, Message<?> message, String name)
 			throws Exception;
 
-	/**
-	 * Resolves the given default value into an argument value.
-	 */
-	private Object resolveDefaultValue(String defaultValue) {
-		if (this.configurableBeanFactory == null) {
-			return defaultValue;
-		}
-		String placeholdersResolved = this.configurableBeanFactory.resolveEmbeddedValue(defaultValue);
-		BeanExpressionResolver exprResolver = this.configurableBeanFactory.getBeanExpressionResolver();
-		if (exprResolver == null) {
-			return defaultValue;
-		}
-		return exprResolver.evaluate(placeholdersResolved, this.expressionContext);
-	}
-
 	/**
 	 * Invoked when a named value is required, but
 	 * {@link #resolveArgumentInternal(MethodParameter, Message, String)} returned {@code null} and

spring-messaging/src/test/java/org/springframework/messaging/handler/annotation/support/HeaderMethodArgumentResolverTests.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.
@@ -34,6 +34,7 @@
 import org.springframework.messaging.handler.annotation.Header;
 import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.messaging.support.NativeMessageHeaderAccessor;
+import org.springframework.util.ReflectionUtils;
 
 import static org.junit.Assert.*;
 
@@ -49,7 +50,8 @@ public class HeaderMethodArgumentResolverTests {
 
 	private MethodParameter paramRequired;
 	private MethodParameter paramNamedDefaultValueStringHeader;
-	private MethodParameter paramSystemProperty;
+	private MethodParameter paramSystemPropertyDefaultValue;
+	private MethodParameter paramSystemPropertyName;
 	private MethodParameter paramNotAnnotated;
 	private MethodParameter paramNativeHeader;
 
@@ -61,13 +63,13 @@ public void setup() throws Exception {
 		cxt.refresh();
 		this.resolver = new HeaderMethodArgumentResolver(new DefaultConversionService(), cxt.getBeanFactory());
 
-		Method method = getClass().getDeclaredMethod("handleMessage",
-				String.class, String.class, String.class, String.class, String.class);
+		Method method = ReflectionUtils.findMethod(getClass(), "handleMessage", (Class<?>[]) null);
 		this.paramRequired = new SynthesizingMethodParameter(method, 0);
 		this.paramNamedDefaultValueStringHeader = new SynthesizingMethodParameter(method, 1);
-		this.paramSystemProperty = new SynthesizingMethodParameter(method, 2);
-		this.paramNotAnnotated = new SynthesizingMethodParameter(method, 3);
-		this.paramNativeHeader = new SynthesizingMethodParameter(method, 4);
+		this.paramSystemPropertyDefaultValue = new SynthesizingMethodParameter(method, 2);
+		this.paramSystemPropertyName = new SynthesizingMethodParameter(method, 3);
+		this.paramNotAnnotated = new SynthesizingMethodParameter(method, 4);
+		this.paramNativeHeader = new SynthesizingMethodParameter(method, 5);
 
 		this.paramRequired.initParameterNameDiscovery(new DefaultParameterNameDiscoverer());
 		GenericTypeResolver.resolveParameterType(this.paramRequired, HeaderMethodArgumentResolver.class);
@@ -84,18 +86,14 @@ public void supportsParameter() {
 	public void resolveArgument() throws Exception {
 		Message<byte[]> message = MessageBuilder.withPayload(new byte[0]).setHeader("param1", "foo").build();
 		Object result = this.resolver.resolveArgument(this.paramRequired, message);
-
 		assertEquals("foo", result);
 	}
 
-	// SPR-11326
-
-	@Test
+	@Test  // SPR-11326
 	public void resolveArgumentNativeHeader() throws Exception {
 		TestMessageHeaderAccessor headers = new TestMessageHeaderAccessor();
 		headers.setNativeHeader("param1", "foo");
 		Message<byte[]> message = MessageBuilder.withPayload(new byte[0]).setHeaders(headers).build();
-
 		assertEquals("foo", this.resolver.resolveArgument(this.paramRequired, message));
 	}
 
@@ -120,7 +118,6 @@ public void resolveArgumentNotFound() throws Exception {
 	public void resolveArgumentDefaultValue() throws Exception {
 		Message<byte[]> message = MessageBuilder.withPayload(new byte[0]).build();
 		Object result = this.resolver.resolveArgument(this.paramNamedDefaultValueStringHeader, message);
-
 		assertEquals("bar", result);
 	}
 
@@ -129,21 +126,34 @@ public void resolveDefaultValueSystemProperty() throws Exception {
 		System.setProperty("systemProperty", "sysbar");
 		try {
 			Message<byte[]> message = MessageBuilder.withPayload(new byte[0]).build();
-			Object result = resolver.resolveArgument(paramSystemProperty, message);
+			Object result = resolver.resolveArgument(paramSystemPropertyDefaultValue, message);
 			assertEquals("sysbar", result);
 		}
 		finally {
 			System.clearProperty("systemProperty");
 		}
 	}
 
+	@Test
+	public void resolveNameFromSystemProperty() throws Exception {
+		System.setProperty("systemProperty", "sysbar");
+		try {
+			Message<byte[]> message = MessageBuilder.withPayload(new byte[0]).setHeader("sysbar", "foo").build();
+			Object result = resolver.resolveArgument(paramSystemPropertyName, message);
+			assertEquals("foo", result);
+		}
+		finally {
+			System.clearProperty("systemProperty");
+		}
+	}
+
 
-	@SuppressWarnings("unused")
-	private void handleMessage(
+	public void handleMessage(
 			@Header String param1,
 			@Header(name = "name", defaultValue = "bar") String param2,
 			@Header(name = "name", defaultValue = "#{systemProperties.systemProperty}") String param3,
-			String param4,
+			@Header(name = "#{systemProperties.systemProperty}") String param4,
+			String param5,
 			@Header("nativeHeaders.param1") String nativeHeaderParam1) {
 	}
 

spring-web/src/main/java/org/springframework/web/method/annotation/AbstractNamedValueMethodArgumentResolver.java

@@ -89,18 +89,24 @@ public final Object resolveArgument(MethodParameter parameter, ModelAndViewConta
 		NamedValueInfo namedValueInfo = getNamedValueInfo(parameter);
 		MethodParameter nestedParameter = parameter.nestedIfOptional();
 
-		Object arg = resolveName(namedValueInfo.name, nestedParameter, webRequest);
+		Object resolvedName = resolveStringValue(namedValueInfo.name);
+		if (resolvedName == null) {
+			throw new IllegalArgumentException(
+					"Specified name must not resolve to null: [" + namedValueInfo.name + "]");
+		}
+
+		Object arg = resolveName(resolvedName.toString(), nestedParameter, webRequest);
 		if (arg == null) {
 			if (namedValueInfo.defaultValue != null) {
-				arg = resolveDefaultValue(namedValueInfo.defaultValue);
+				arg = resolveStringValue(namedValueInfo.defaultValue);
 			}
 			else if (namedValueInfo.required && !nestedParameter.isOptional()) {
 				handleMissingValue(namedValueInfo.name, nestedParameter, webRequest);
 			}
 			arg = handleNullValue(namedValueInfo.name, arg, nestedParameter.getNestedParameterType());
 		}
 		else if ("".equals(arg) && namedValueInfo.defaultValue != null) {
-			arg = resolveDefaultValue(namedValueInfo.defaultValue);
+			arg = resolveStringValue(namedValueInfo.defaultValue);
 		}
 
 		if (binderFactory != null) {
@@ -162,6 +168,22 @@ private NamedValueInfo updateNamedValueInfo(MethodParameter parameter, NamedValu
 		return new NamedValueInfo(name, info.required, defaultValue);
 	}
 
+	/**
+	 * Resolve the given annotation-specified value,
+	 * potentially containing placeholders and expressions.
+	 */
+	private Object resolveStringValue(String value) {
+		if (this.configurableBeanFactory == null) {
+			return value;
+		}
+		String placeholdersResolved = this.configurableBeanFactory.resolveEmbeddedValue(value);
+		BeanExpressionResolver exprResolver = this.configurableBeanFactory.getBeanExpressionResolver();
+		if (exprResolver == null) {
+			return value;
+		}
+		return exprResolver.evaluate(placeholdersResolved, this.expressionContext);
+	}
+
 	/**
 	 * Resolve the given parameter type and value name into an argument value.
 	 * @param name the name of the value being resolved
@@ -174,21 +196,6 @@ private NamedValueInfo updateNamedValueInfo(MethodParameter parameter, NamedValu
 	protected abstract Object resolveName(String name, MethodParameter parameter, NativeWebRequest request)
 			throws Exception;
 
-	/**
-	 * Resolve the given default value into an argument value.
-	 */
-	private Object resolveDefaultValue(String defaultValue) {
-		if (this.configurableBeanFactory == null) {
-			return defaultValue;
-		}
-		String placeholdersResolved = this.configurableBeanFactory.resolveEmbeddedValue(defaultValue);
-		BeanExpressionResolver exprResolver = this.configurableBeanFactory.getBeanExpressionResolver();
-		if (exprResolver == null) {
-			return defaultValue;
-		}
-		return exprResolver.evaluate(placeholdersResolved, this.expressionContext);
-	}
-
 	/**
 	 * Invoked when a named value is required, but {@link #resolveName(String, MethodParameter, NativeWebRequest)}
 	 * returned {@code null} and there is no default value. Subclasses typically throw an exception in this case.

spring-web/src/test/java/org/springframework/web/method/annotation/RequestHeaderMethodArgumentResolverTests.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.
@@ -27,6 +27,7 @@
 import org.springframework.core.annotation.SynthesizingMethodParameter;
 import org.springframework.mock.web.test.MockHttpServletRequest;
 import org.springframework.mock.web.test.MockHttpServletResponse;
+import org.springframework.util.ReflectionUtils;
 import org.springframework.web.bind.ServletRequestBindingException;
 import org.springframework.web.bind.annotation.RequestHeader;
 import org.springframework.web.context.request.NativeWebRequest;
@@ -50,6 +51,7 @@ public class RequestHeaderMethodArgumentResolverTests {
 	private MethodParameter paramNamedValueStringArray;
 	private MethodParameter paramSystemProperty;
 	private MethodParameter paramContextPath;
+	private MethodParameter paramResolvedName;
 	private MethodParameter paramNamedValueMap;
 
 	private MockHttpServletRequest servletRequest;
@@ -64,12 +66,13 @@ public void setUp() throws Exception {
 		context.refresh();
 		resolver = new RequestHeaderMethodArgumentResolver(context.getBeanFactory());
 
-		Method method = getClass().getMethod("params", String.class, String[].class, String.class, String.class, Map.class);
+		Method method = ReflectionUtils.findMethod(getClass(), "params", (Class<?>[]) null);
 		paramNamedDefaultValueStringHeader = new SynthesizingMethodParameter(method, 0);
 		paramNamedValueStringArray = new SynthesizingMethodParameter(method, 1);
 		paramSystemProperty = new SynthesizingMethodParameter(method, 2);
 		paramContextPath = new SynthesizingMethodParameter(method, 3);
-		paramNamedValueMap = new SynthesizingMethodParameter(method, 4);
+		paramResolvedName = new SynthesizingMethodParameter(method, 4);
+		paramNamedValueMap = new SynthesizingMethodParameter(method, 5);
 
 		servletRequest = new MockHttpServletRequest();
 		webRequest = new ServletWebRequest(servletRequest, new MockHttpServletResponse());
@@ -97,45 +100,61 @@ public void resolveStringArgument() throws Exception {
 		servletRequest.addHeader("name", expected);
 
 		Object result = resolver.resolveArgument(paramNamedDefaultValueStringHeader, null, webRequest, null);
-
 		assertTrue(result instanceof String);
 		assertEquals("Invalid result", expected, result);
 	}
 
 	@Test
 	public void resolveStringArrayArgument() throws Exception {
-		String[] expected = new String[]{"foo", "bar"};
+		String[] expected = new String[] {"foo", "bar"};
 		servletRequest.addHeader("name", expected);
 
 		Object result = resolver.resolveArgument(paramNamedValueStringArray, null, webRequest, null);
-
 		assertTrue(result instanceof String[]);
 		assertArrayEquals("Invalid result", expected, (String[]) result);
 	}
 
 	@Test
 	public void resolveDefaultValue() throws Exception {
 		Object result = resolver.resolveArgument(paramNamedDefaultValueStringHeader, null, webRequest, null);
-
 		assertTrue(result instanceof String);
 		assertEquals("Invalid result", "bar", result);
 	}
 
 	@Test
 	public void resolveDefaultValueFromSystemProperty() throws Exception {
 		System.setProperty("systemProperty", "bar");
-		Object result = resolver.resolveArgument(paramSystemProperty, null, webRequest, null);
-		System.clearProperty("systemProperty");
+		try {
+			Object result = resolver.resolveArgument(paramSystemProperty, null, webRequest, null);
+			assertTrue(result instanceof String);
+			assertEquals("bar", result);
+		}
+		finally {
+			System.clearProperty("systemProperty");
+		}
+	}
 
-		assertTrue(result instanceof String);
-		assertEquals("bar", result);
+	@Test
+	public void resolveNameFromSystemProperty() throws Exception {
+		String expected = "foo";
+		servletRequest.addHeader("bar", expected);
+
+		System.setProperty("systemProperty", "bar");
+		try {
+			Object result = resolver.resolveArgument(paramResolvedName, null, webRequest, null);
+			assertTrue(result instanceof String);
+			assertEquals("Invalid result", expected, result);
+		}
+		finally {
+			System.clearProperty("systemProperty");
+		}
 	}
 
 	@Test
 	public void resolveDefaultValueFromRequest() throws Exception {
 		servletRequest.setContextPath("/bar");
-		Object result = resolver.resolveArgument(paramContextPath, null, webRequest, null);
 
+		Object result = resolver.resolveArgument(paramContextPath, null, webRequest, null);
 		assertTrue(result instanceof String);
 		assertEquals("/bar", result);
 	}
@@ -146,11 +165,13 @@ public void notFound() throws Exception {
 	}
 
 
-	public void params(@RequestHeader(name = "name", defaultValue = "bar") String param1,
-					   @RequestHeader("name") String[] param2,
-					   @RequestHeader(name = "name", defaultValue="#{systemProperties.systemProperty}") String param3,
-					   @RequestHeader(name = "name", defaultValue="#{request.contextPath}") String param4,
-					   @RequestHeader("name") Map<?, ?> unsupported) {
+	public void params(
+			@RequestHeader(name = "name", defaultValue = "bar") String param1,
+			@RequestHeader("name") String[] param2,
+			@RequestHeader(name = "name", defaultValue="#{systemProperties.systemProperty}") String param3,
+			@RequestHeader(name = "name", defaultValue="#{request.contextPath}") String param4,
+			@RequestHeader("#{systemProperties.systemProperty}") String param5,
+			@RequestHeader("name") Map<?, ?> unsupported) {
 	}
 
 }