Code completion with CompletionContributor

I am developing a plugin for PhpStorm, and I want to provide code completion when the user, for example, calls a method on a class like User::find(""). I want to suggest words which a define to the user when the cursor is between the double quotes.

This is my code. It works for all double quotes, but I want it to work only when the user is inside the "" of a method
public class ModelFieldCompletion extends CompletionContributor {
    public ModelFieldCompletion() {
        extend(CompletionType.BASIC, PlatformPatterns.psiElement(PhpTokenTypes.STRING_LITERAL),
                new CompletionProvider<>() {
                    public void addCompletions(@NotNull CompletionParameters parameters,
                                               @NotNull ProcessingContext context,
                                               @NotNull CompletionResultSet resultSet) {
                        String[] suggestions = {"hello", "world", "example", "suggestion"};

                        // Iterate over the array and add each string as a suggestion
                        for (String suggestion : suggestions) {

Does anyone know what I need to add or what I still have to do to achieve this?