Spring PlaceholderResolver

	@FunctionalInterface
	public interface PlaceholderResolver {

		/**
		 * Resolve the supplied placeholder name to the replacement value.
		 * @param placeholderName the name of the placeholder to resolve
		 * @return the replacement value, or {@code null} if no replacement is to be made
		 */
		@Nullable
		String resolvePlaceholder(String placeholderName);
	}