Polish MessageHeaderAccessor

Issue: SPR-12431

spring-messaging/src/main/java/org/springframework/messaging/support/MessageHeaderAccessor.java

@@ -22,7 +22,6 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import java.util.UUID;
 
 import org.apache.commons.logging.Log;
@@ -373,9 +372,9 @@ public class MessageHeaderAccessor {
 	private List<String> getMatchingHeaderNames(String pattern, Map<String, Object> headers) {
 		List<String> matchingHeaderNames = new ArrayList<String>();
 		if (headers != null) {
-			for (Map.Entry<String, Object> header: headers.entrySet()) {
+			for (String key : headers.keySet()) {
-				if (PatternMatchUtils.simpleMatch(pattern,  header.getKey())) {
+				if (PatternMatchUtils.simpleMatch(pattern, key)) {
-					matchingHeaderNames.add(header.getKey());
+					matchingHeaderNames.add(key);
 				}
 			}
 		}
@@ -389,10 +388,9 @@ public class MessageHeaderAccessor {
 	 */
 	public void copyHeaders(Map<String, ?> headersToCopy) {
 		if (headersToCopy != null) {
-			Set<String> keys = headersToCopy.keySet();
+			for (Map.Entry<String, ?> entry : headersToCopy.entrySet()) {
-			for (String key : keys) {
+				if (!isReadOnly(entry.getKey())) {
-				if (!isReadOnly(key)) {
+					setHeader(entry.getKey(), entry.getValue());
-					setHeader(key, headersToCopy.get(key));
 				}
 			}
 		}
@@ -404,10 +402,9 @@ public class MessageHeaderAccessor {
 	 */
 	public void copyHeadersIfAbsent(Map<String, ?> headersToCopy) {
 		if (headersToCopy != null) {
-			Set<String> keys = headersToCopy.keySet();
+			for (Map.Entry<String, ?> entry : headersToCopy.entrySet()) {
-			for (String key : keys) {
+				if (!isReadOnly(entry.getKey())) {
-				if (!isReadOnly(key)) {
+					setHeaderIfAbsent(entry.getKey(), entry.getValue());
-					setHeaderIfAbsent(key, headersToCopy.get(key));
 				}
 			}
 		}

spring-messaging/src/test/java/org/springframework/messaging/support/MessageHeaderAccessorTests.java

@@ -39,6 +39,7 @@ import static org.junit.Assert.*;
  * Test fixture for {@link MessageHeaderAccessor}.
  *
  * @author Rossen Stoyanchev
+ * @author Sebastien Deleuze
  */
 public class MessageHeaderAccessorTests {
 
@@ -88,6 +89,58 @@ public class MessageHeaderAccessorTests {
 		assertEquals("baz", actual.get("bar"));
 	}
 
+	@Test
+	public void removeHeaders() {
+		Map<String, Object> map = new HashMap<>();
+		map.put("foo", "bar");
+		map.put("bar", "baz");
+		GenericMessage<String> message = new GenericMessage<>("payload", map);
+		MessageHeaderAccessor accessor = new MessageHeaderAccessor(message);
+
+		accessor.removeHeaders("fo*");
+
+		MessageHeaders actual = accessor.getMessageHeaders();
+		assertEquals(2, actual.size());
+		assertNull(actual.get("foo"));
+		assertEquals("baz", actual.get("bar"));
+	}
+
+	@Test
+	public void copyHeaders() {
+		Map<String, Object> map1 = new HashMap<>();
+		map1.put("foo", "bar");
+		GenericMessage<String> message = new GenericMessage<>("payload", map1);
+		MessageHeaderAccessor accessor = new MessageHeaderAccessor(message);
+
+		Map<String, Object> map2 = new HashMap<>();
+		map2.put("foo", "BAR");
+		map2.put("bar", "baz");
+		accessor.copyHeaders(map2);
+
+		MessageHeaders actual = accessor.getMessageHeaders();
+		assertEquals(3, actual.size());
+		assertEquals("BAR", actual.get("foo"));
+		assertEquals("baz", actual.get("bar"));
+	}
+
+	@Test
+	public void copyHeadersIfAbsent() {
+		Map<String, Object> map1 = new HashMap<>();
+		map1.put("foo", "bar");
+		GenericMessage<String> message = new GenericMessage<>("payload", map1);
+		MessageHeaderAccessor accessor = new MessageHeaderAccessor(message);
+
+		Map<String, Object> map2 = new HashMap<>();
+		map2.put("foo", "BAR");
+		map2.put("bar", "baz");
+		accessor.copyHeadersIfAbsent(map2);
+
+		MessageHeaders actual = accessor.getMessageHeaders();
+		assertEquals(3, actual.size());
+		assertEquals("bar", actual.get("foo"));
+		assertEquals("baz", actual.get("bar"));
+	}
+
 	@Test
 	public void copyHeadersFromNullMap() {
 		MessageHeaderAccessor headers = new MessageHeaderAccessor();