What is the alternative for String.format() in GWT?

Question

While GWT is not emulate all java's core, what can be used as alternative for:

String.format("The answer is - %d", 42)? 

What is the ellegant and efficient pattern to inject arguments to message in GWT?

Answer 1

One elegant solution is using SafeHtml templates. You can define multiple such templates in an interface like:

public interface MyTemplates extends SafeHtmlTemplates {   @Template("The answer is - {0}")   SafeHtml answer(int value);    @Template("...")   ... } 

And then use them:

public static final MyTemplates TEMPLATES = GWT.create(MyTemplates.class);  ... Label label = new Label(TEMPLATES.answer(42)); 

While this is a little bit more work to set up, it has the enormous advantage that arguments are automatically HTML-escaped. For more info, see https://developers.google.com/web-toolkit/doc/latest/DevGuideSecuritySafeHtml

If you want to go one step further, and internationalize your messages, then see also https://developers.google.com/web-toolkit/doc/latest/DevGuideI18nMessages#SafeHtmlMessages

Answer 2

You can simply write your own format function instead of doing brain storm.

public static String format(final String format, final String... args,String delimiter) {     String[] split = format.split(delimiter);//in your case "%d" as delimeter     final StringBuffer buffer= new StringBuffer();     for (int i= 0; i< split.length - 1; i+= 1) {         buffer.append(split[i]);         buffer.append(args[i]);     }     buffer.append(split[split.length - 1]);     return buffer.toString();  }