PrimeFaces p:autoComplete over List of Objects, failed Conversion

Question

I'm having some trouble using p:autoComplete properly, I am trying to let a user search based on a text field of an object. Currently I have the following:

<p:autoComplete forceSelection="true" value="#{answer.destinationQuestion}"
                completeMethod="#{editorView.completeText}"
                var="destinationQuestion" itemLabel="#{destinationQuestion.questionText}"
                itemValue="#{destinationQuestion}"/>

public List<Question> completeText(String query) {
        List<Question> ret = new ArrayList<Question>();
        
        for(Section section : this.survey.getSections()) {
            for(Question question : section.getQuestion()) {
                if(question.getQuestionText() != null && question.getQuestionText().contains(query)) {
                    ret.add(question);
                }
            }
        }
        
        return ret;
    }

My expectation with this code is that the autoComplete would let a user select a single Question instance, but once a value is selected from the autoComplete and an update event is triggered, I receive the following exception:

java.lang.IllegalArgumentException: Cannot convert Question@228bb9f7 of type class java.lang.String to class Question

It has been suggested that I use a converter, but I am confused why the value selected is being treated as a String rather than my Question object, since itemValue is defined to be a Question object.

Edit: This is on PrimeFaces 6.2

Answer 1

Based on your code, what I can tell you is, you are missing a custom converter class. You should use it like converter="#{questionConverter}".

For further reference you can see this