Use Regular Expressions in JPA CriteriaBuilder

Question

I\'m using the JPA CriteriaBuilder to select entities of type MyEntity from a MySQL db as follows:

String regExp = \"(abc|def)\"
CriteriaBuilder         


        

Answer 1

Maybe this snippet will help. We had to exclude characters in a search, and we using Oracle. CriteriaBuilder (at least as of 2.1) will let you call a function.

private static final Pattern UNDESIRABLES = Pattern.compile("[(){},.;!?<>%_-]");
private static final String UNDESIRABLE_REPLACEMENT = "";
...

In the search method, create a Predicate to use in your where clause:

Expression undesirables = cb.literal(UNDESIRABLES.toString());
Expression replaceWith = cb.literal(UNDESIRABLE_REPLACEMENT);
Expression regExp = cb.function("REGEXP_REPLACE", String.class, client.get(Client_.companyName),
    undesirables, replaceWith);
Predicate companyNameMatch = cb.equal(cb.trim(cb.lower(regExp)), removeUndesireables(name).trim());
...

And create a method for the right hand comapare that uses the same values as the left:

private String removeUndesireables(String name) {
    return UNDESIRABLES.matcher(name).replaceAll(UNDESIRABLE_REPLACEMENT).toLowerCase();
}