I would like to create a list of up to three items using a template fragment. Three spaces for items will always be displayed regardless of whether or not there is an item, so it looks something like this.
<div>
<div th:if="${#lists.size(block.children) > 0}"
th:insert="code-block :: block(${block.children[0]})"
th:remove="tag">
</div>
</div>;
<div>
<div th:if="${#lists.size(block.children) > 1}"
th:insert="code-block :: block(${block.children[1]})"
th:remove="tag">
</div>
</div>;
<div>
<div th:if="${#lists.size(block.children) > 2}"
th:insert="code-block :: block(${block.children[2]})"
th:remove="tag">
</div>
</div>
However, even though the th:if statement evaluates as false with an empty list, it still attempts to execute the `th:include statement, giving me the following error:
Caused by: org.springframework.expression.spel.SpelEvaluationException:
EL1025E:(pos 14): The collection has '0' elements, index '0' is invalid
How can I get the if statement to take precedence over the fragment execution?
Yeah, unfortunately since include has precedence over if, you're going to have to move the if higher up. The simplest way would be to put it in a th:block, like this:
<div>
<th:block th:if="${#lists.size(block.children) > 0}">
<div th:insert="code-block :: block(${block.children[0]})" th:remove="tag" />
</th:block>
</div>;
<div>
<th:block th:if="${#lists.size(block.children) > 1}">
<div th:insert="code-block :: block(${block.children[1]})" th:remove="tag" />
</th:block>
</div>;
<div>
<th:block th:if="${#lists.size(block.children) > 2}">
<div th:insert="code-block :: block(${block.children[2]})" th:remove="tag" />
</th:block>
</div>
You could also probably simplify your code to look something more like this:
<th:block th:each="i: ${#numbers.sequence(0, 2)}">
<th:block th:if="${#lists.size(block.children) > i}">
<div th:insert="code-block :: block(${block.children[i]})" th:remove="tag" />
</th:block>
<th:block th:unless="${i == 2}">;</th:block>
</th:block>