This can be leveraged to check the last modification timestamp and to load - * properties from alternative sources. For example an XML blob in a database, or - * properties serialized in a custom format like JSON... - *
The default implementation first checks for an existing file Resource with the - * {@code .properties} extension, and otherwise returns a file Resource with the - * {@code .xml} extension. - *
When overriding this method, {@link #loadProperties(Resource, String)} MUST be - * capable of loading properties from any of the {@link Resource} this method can return. - * As a consequence, implementors are strongly encouraged to also override - * {@link #loadProperties(Resource, String)}. - *
As an alternative, one could set the {@link #setPropertiesPersister(PropertiesPersister)} - * with an instance capable of dealing with all resources returned by this method. - * Please note however that the default {@code loadProperties} detects XML resource - * filenames and uses {@link PropertiesPersister#loadFromXml(Properties, InputStream)}, - * and the two {@link PropertiesPersister#load(Properties, InputStream) load} methods - * otherwise. + * Resolve the specified bundle {@code filename} into a concrete {@link Resource}, + * potentially checking multiple sources or file extensions. + *
If no suitable concrete {@code Resource} can be resolved, this method + * returns a {@code Resource} for which {@link Resource#exists()} returns + * {@code false}, which gets subsequently ignored. + *
This can be leveraged to check the last modification timestamp or to load + * properties from alternative sources — for example, from an XML BLOB + * in a database, or from properties serialized using a custom format such as + * JSON. + *
The default implementation delegates to the configured + * {@link #setResourceLoader(ResourceLoader) ResourceLoader} to resolve + * resources, first checking for an existing {@code Resource} with a + * {@code .properties} extension, and otherwise returning a {@code Resource} + * with a {@code .xml} extension. + *
When overriding this method, {@link #loadProperties(Resource, String)} + * must be capable of loading properties from any type of + * {@code Resource} returned by this method. As a consequence, implementors + * are strongly encouraged to also override {@code loadProperties()}. + *
As an alternative to overriding this method, you can configure a + * {@link #setPropertiesPersister(PropertiesPersister) PropertiesPersister} + * that is capable of dealing with all resources returned by this method. + * Please note, however, that the default {@code loadProperties()} implementation + * uses {@link PropertiesPersister#loadFromXml(Properties, InputStream) loadFromXml} + * for XML resources and otherwise uses the two + * {@link PropertiesPersister#load(Properties, InputStream) load} methods + * for other types of resources. + * @param filename the bundle filename (basename + Locale) * @return the {@code Resource} to use - * @since 6.1.0 + * @since 6.1 */ protected Resource determineResource(String filename) { Resource propertiesResource = this.resourceLoader.getResource(filename + PROPERTIES_SUFFIX); @@ -432,10 +439,11 @@ public class ReloadableResourceBundleMessageSource extends AbstractResourceBased /** * Refresh the PropertiesHolder for the given bundle filename. - * The holder can be {@code null} if not cached before, or a timed-out cache entry + *
The holder can be {@code null} if not cached before, or a timed-out cache entry * (potentially getting re-validated against the current last-modified timestamp). * @param filename the bundle filename (basename + Locale) * @param propHolder the current PropertiesHolder for the bundle + * @see #determineResource(String) */ protected PropertiesHolder refreshProperties(String filename, @Nullable PropertiesHolder propHolder) { long refreshTimestamp = (getCacheMillis() < 0 ? -1 : System.currentTimeMillis());