Controller for autocomplete page

AutocompleteController.java

public class AutoCompleteController {

    //String property to pass JSON data to page
    public String toEmailJSON{get;set;} 
    //String property to save the values selected by user
    public String selectedEmails{get;set;} 
    
    //Constructor of the class where email addresses are obtained from custom setting and converted to JSON
    public autocompleteController(){
        Set<String> autocompleteEmailSet = AutocompleteEmails__c.getAll().keyset();
        toEmailJSON = JSON.serialize(autocompleteEmailSet);
    }
    
    //Method to demonstrate that values are coming to controller on button click
    public PageReference receiveValues() {
        //Debugging the value passed from page
        System.debug(selectedEmails);
        return null;
    }
}