ResourceBundleThemeSource exposes fallbackToSystemLocale and defaultEncoding

Issue: SPR-13209

spring-context/src/main/java/org/springframework/ui/context/support/ResourceBundleThemeSource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -16,12 +16,13 @@
 
 package org.springframework.ui.context.support;
 
-import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.context.HierarchicalMessageSource;
 import org.springframework.context.MessageSource;
 import org.springframework.context.support.ResourceBundleMessageSource;
@@ -41,7 +42,7 @@ import org.springframework.ui.context.ThemeSource;
  * @see java.util.ResourceBundle
  * @see org.springframework.context.support.ResourceBundleMessageSource
  */
-public class ResourceBundleThemeSource implements HierarchicalThemeSource {
+public class ResourceBundleThemeSource implements HierarchicalThemeSource, BeanClassLoaderAware {
 
 	protected final Log logger = LogFactory.getLog(getClass());
 
@@ -49,8 +50,14 @@ public class ResourceBundleThemeSource implements HierarchicalThemeSource {
 
 	private String basenamePrefix = "";
 
+	private String defaultEncoding;
+
+	private Boolean fallbackToSystemLocale;
+
+	private ClassLoader beanClassLoader;
+
 	/** Map from theme name to Theme instance */
-	private final Map<String, Theme> themeCache = new HashMap<String, Theme>();
+	private final Map<String, Theme> themeCache = new ConcurrentHashMap<String, Theme>();
 
 
 	@Override
@@ -85,6 +92,33 @@ public class ResourceBundleThemeSource implements HierarchicalThemeSource {
 		this.basenamePrefix = (basenamePrefix != null ? basenamePrefix : "");
 	}
 
+	/**
+	 * Set the default charset to use for parsing resource bundle files.
+	 * <p>{@link ResourceBundleMessageSource}'s default is the
+	 * {@code java.util.ResourceBundle} default encoding: ISO-8859-1.
+	 * @since 4.2
+	 * @see ResourceBundleMessageSource#setDefaultEncoding
+	 */
+	public void setDefaultEncoding(String defaultEncoding) {
+		this.defaultEncoding = defaultEncoding;
+	}
+
+	/**
+	 * Set whether to fall back to the system Locale if no files for a
+	 * specific Locale have been found.
+	 * <p>{@link ResourceBundleMessageSource}'s default is "true".
+	 * @since 4.2
+	 * @see ResourceBundleMessageSource#setFallbackToSystemLocale
+	 */
+	public void setFallbackToSystemLocale(boolean fallbackToSystemLocale) {
+		this.fallbackToSystemLocale = fallbackToSystemLocale;
+	}
+
+	@Override
+	public void setBeanClassLoader(ClassLoader beanClassLoader) {
+		this.beanClassLoader = beanClassLoader;
+	}
+
 
 	/**
 	 * This implementation returns a SimpleTheme instance, holding a
@@ -100,8 +134,10 @@ public class ResourceBundleThemeSource implements HierarchicalThemeSource {
 		if (themeName == null) {
 			return null;
 		}
-		synchronized (this.themeCache) {
 		Theme theme = this.themeCache.get(themeName);
+		if (theme == null) {
+			synchronized (this.themeCache) {
+				theme = this.themeCache.get(themeName);
 				if (theme == null) {
 					String basename = this.basenamePrefix + themeName;
 					MessageSource messageSource = createMessageSource(basename);
@@ -112,9 +148,10 @@ public class ResourceBundleThemeSource implements HierarchicalThemeSource {
 						logger.debug("Theme created: name '" + themeName + "', basename [" + basename + "]");
 					}
 				}
-			return theme;
 			}
 		}
+		return theme;
+	}
 
 	/**
 	 * Create a MessageSource for the given basename,
@@ -130,6 +167,15 @@ public class ResourceBundleThemeSource implements HierarchicalThemeSource {
 	protected MessageSource createMessageSource(String basename) {
 		ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
 		messageSource.setBasename(basename);
+		if (this.defaultEncoding != null) {
+			messageSource.setDefaultEncoding(this.defaultEncoding);
+		}
+		if (this.fallbackToSystemLocale != null) {
+			messageSource.setFallbackToSystemLocale(this.fallbackToSystemLocale);
+		}
+		if (this.beanClassLoader != null) {
+			messageSource.setBeanClassLoader(this.beanClassLoader);
+		}
 		return messageSource;
 	}