Thymeleaf - how to add a custom util?

Question

Thymeleaf has a number of useful utilities like #strings.capitalize(...) or #lists.isEmpty(...). I'm trying to add a custom one but have no idea how to register this.

Have made a custom Util class:

public class LabelUtil {

    public String[] splitDoubleWord(String str) {
        return str.split("[A-Z]", 1);
    }
}

Now I'm going to use it like this:

<span th:each="item : ${#labels.splitDoubleWord(name)}" th:text="${item}"></span>

Of course, it won't work because I haven't registered the Util and defined #labels var.

So, the question is how and where to do it?

Answer 1

The API for registering a custom expression object has changed in Thymeleaf 3, for example:

public class MyDialect extends AbstractDialect implements IExpressionObjectDialect {

    MyDialect() {
        super("My Dialect");
    }

    @Override
    public IExpressionObjectFactory getExpressionObjectFactory() {
        return new IExpressionObjectFactory() {

            @Override
            public Set<String> getAllExpressionObjectNames() {
                return Collections.singleton("myutil");
            }

            @Override
            public Object buildObject(IExpressionContext context,
                    String expressionObjectName) {
                return new MyUtil();
            }

            @Override
            public boolean isCacheable(String expressionObjectName) {
                return true;
            }
        };
    }
}