package lambdausage;

public interface Writer {
    Writer w(String text);
}

package lambdausage;

public class Writers {

    public static Writer writerOf_sugared(StringBuilder sb) {
        return text -> {
            sb.append(text);
            return что-то-вроде-Writer.this;
        };
    }

    public static Writer writerOf(StringBuilder sb) {
        return new Writer() {
            @Override public Writer w(String text) {
                sb.append(text);
                return this;
            }
        };
    }
}