Folks, this isn’t by any means a show of brilliant software engineering, but I didn’t find anything exactly like it in the blogosphere. I have a really basic scenario to solve. I have a JQuery grid in a jsp with filterable columns which are mapped via Stripes MVC and Spring to a JPA Entity.
The ajax call from JQuery gives me name/value pairs to filter. It also gives me the row number to begin the page with and how many rows to retrieve. From this, I can filter the entity list without hard-coding the Predicates or without building a JPQL string. The following method goes in Spring Repository or where ever you are keeping business logic for entities.
Step 1: #44 – Get a CriteriaBuilder from the entity manager
Step 2: #47 – Get a Root of type <YourEntity>
Step 3: #49 – declare a collection of Predicates
Step 4: #60 – For each name/value pair, instantiate a new Like Predicate and add it to the list. Use The % sign around the data for wildcard searching
Step 5: #62 – Add all predicates to the query’s where clause
Step 6: #63 – create TypedQuery from the CriteriaQuery
Step 7: #70 – set the first row for your page
Step 8: #71 – set your max your for your page
Step 9: #72 – retrieve the data
Thanks for reading! If you would like to see what else I’m up to, check out Whiff