I need to create a "real" dynamic JPA CriteriaBuilder
. I get an Map<String, String>
with the statements. It looks like:
name : John
surname : Smith
email : [email protected]
...more pairs possible
Here is what i implement:
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<User> query = cb.createQuery(User.class);
Root<User> userRoot = query.from(User.class);
query.select(userRoot);
List<Predicate> predicates = new ArrayList<Predicate>();
Iterator<String> column = statements.keySet().iterator();
while (column.hasNext()) {
// get the pairs
String colIndex = column.next();
String colValue = statements.get(colIndex);
// create the statement
Predicate pAnd = cb.conjunction();
pAnd = cb.and(pAnd, cb.equal(userRoot.get(colIndex), colValue));
predicates.add(pAnd);
}
// doesn't work, i don't know how many predicates i have -> can not address them
query.where(predicates.get(0), predicates.get(1), ...);
// doesn't work, because it is a list of predicates
query.where(predicates);
// doesn't work, because the actual predicate overwrites the old predicate
for (Predicate pre : predicates) {
query.where(pre)
}
I tried to build a big Predicate
, which contains all other predicates and add this to the query.where()
, but again the predicates overwrites old values. Looks like there is no possibility to add a Predicate
instead of change a Predicate :-(
The real project is even more complicated, because some pairs requires an equal
and some other a like
. And that is not even enough: There could a extra statement with or
included like type : 1;4;7
. Here the value have to split up and create a statement like:
<rest of statement> AND (type = 1 OR type = 4 OR type = 7)
UPDATE and SOLUTION Got two lists, first List for AND works well. Second list contains OR statements like exspected:
final List<Predicate> andPredicates = new ArrayList<Predicate>();
final List<Predicate> orPredicates = new ArrayList<Predicate>();
for (final Entry<String, String> entry : statements.entrySet()) {
final String colIndex = entry.getKey();
final String colValue = entry.getValue();
if (colIndex != null && colValue != null) {
if (!colValue.contains(";")) {
if (equals) {
andPredicates.add(cb.equal(userRoot.get(colIndex), colValue));
} else {
andPredicates.add(cb.like(userRoot.<String> get(colIndex), "%" + colValue + "%"));
}
} else {
String[] values = colValue.split(";");
for (String value : values) {
orPredicates.add(cb.or(cb.equal(userRoot.get(colIndex), value)));
}
}
}
}
// Here goes the magic to combine both lists
if (andPredicates.size() > 0 && orPredicates.size() == 0) {
// no need to make new predicate, it is already a conjunction
query.where(andPredicates.toArray(new Predicate[andPredicates.size()]));
} else if (andPredicates.size() == 0 && orPredicates.size() > 0) {
// make a disjunction, this part is missing above
Predicate p = cb.disjunction();
p = cb.or(orPredicates.toArray(new Predicate[orPredicates.size()]));
query.where(p);
} else {
// both types of statements combined
Predicate o = cb.and(andPredicates.toArray(new Predicate[andPredicates.size()]));
Predicate p = cb.or(orPredicates.toArray(new Predicate[orPredicates.size()]));
query.where(o, p);
}
query.where(predicates.toArray(new Predicate[predicates.size()]));
users = em.createQuery(query).getResultList();
You can pass an array of predicates to the CriteriaBuilder
, deciding on equal
or like
as you go. For this, build a list and pack the contents of the list into an array in a single and
statement. Like this:
final List<Predicate> predicates = new ArrayList<Predicate>();
for (final Entry<String, String> e : myPredicateMap.entrySet()) {
final String key = e.getKey();
final String value = e.getValue();
if ((key != null) && (value != null)) {
if (value.contains("%")) {
predicates.add(criteriaBuilder.like(root.<String> get(key), value));
} else {
predicates.add(criteriaBuilder.equal(root.get(key), value));
}
}
}
query.where(criteriaBuilder.and(predicates.toArray(new Predicate[predicates.size()])));
query.select(count);
In case you need to distingiush between and
and or
, use two lists.