Use separately defined Key as composite key in StaticMessageSource

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -36,21 +36,20 @@
  */
 public class StaticMessageSource extends AbstractMessageSource {
 
-	/** Map from 'code + locale' keys to message Strings. */
-	private final Map<String, String> messages = new HashMap<>();
+	private final Map<Key, String> messages = new HashMap<>();
 
-	private final Map<String, MessageFormat> cachedMessageFormats = new HashMap<>();
+	private final Map<Key, MessageFormat> cachedMessageFormats = new HashMap<>();
 
 
 	@Override
 	protected String resolveCodeWithoutArguments(String code, Locale locale) {
-		return this.messages.get(code + '_' + locale.toString());
+		return this.messages.get(new Key(code, locale));
 	}
 
 	@Override
 	@Nullable
 	protected MessageFormat resolveCode(String code, Locale locale) {
-		String key = code + '_' + locale.toString();
+		Key key = new Key(code, locale);
 		String msg = this.messages.get(key);
 		if (msg == null) {
 			return null;
@@ -75,7 +74,7 @@ public void addMessage(String code, Locale locale, String msg) {
 		Assert.notNull(code, "Code must not be null");
 		Assert.notNull(locale, "Locale must not be null");
 		Assert.notNull(msg, "Message must not be null");
-		this.messages.put(code + '_' + locale.toString(), msg);
+		this.messages.put(new Key(code, locale), msg);
 		if (logger.isDebugEnabled()) {
 			logger.debug("Added message [" + msg + "] for code [" + code + "] and Locale [" + locale + "]");
 		}
@@ -98,4 +97,27 @@ public String toString() {
 		return getClass().getName() + ": " + this.messages;
 	}
 
+	private static final class Key {
+		private final String code;
+		private final Locale locale;
+
+		private Key(String code, Locale locale) {
+			this.code = code;
+			this.locale = locale;
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (this == o) return true;
+			if (o == null || getClass() != o.getClass()) return false;
+			Key key = (Key) o;
+			return code.equals(key.code) && locale.equals(key.locale);
+		}
+
+		@Override
+		public int hashCode() {
+			return 31 * code.hashCode() + locale.hashCode();
+		}
+	}
+
 }