th:style isn't working in my project depending on case true:false

My text have to change color depending on true:false case using Thymeleaf, but whatever I did it doesn't work.

    <table th:each="book : ${assignedBooks}">
        <tr th:style="${book.getExpired()? 'color: red;' : 'color: blue;'}" th:text="${book.getName() + ', ' + book.getAuthor() + ', ' + book.getYear()}">'someBook'</tr>
    </table>

I have checked .getExpired == true, but I don't understand why it still doesn't work.

This is a revised version of your codebase and should work.

I will explain the changes I carried out.

<table th:each="book : ${assignedBooks}">
    <tr th:style="${book.expired} ? 'color: red;' : 'color: blue;'"> 
        <td th:text="${book.name + ', ' + book.author + ', ' + book.year}">someBook</td>
    </tr>
</table>

• I've shortened book.getExpired() to book.expired. Thymeleaf can directly interpret boolean properties.
• Removed Quotes: I've removed the quotes around 'someBook'. Thymeleaf treats content within the or as text to be displayed.

Additional Tips:

• Debugging: Add temporary th:text elements within your table row to output the values of book.name, book.author, etc., to ensure the data is being fetched properly.
• Verify book.expired: Double-check that your book.expired property is indeed returning a boolean (true or false) as expected. You can temporarily add a th:text="${book.expired}" somewhere inside the element to check.