[OPENJPA-2501] MapJoin key() throws NullPointerException

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.2.3
• Component/s: criteria, kernel
• Environment: openjpa-2.2.3-SNAPSHOT-r422266; used in IBM Websphere Liberty profile build 8.5.5.1-cl50120131011-1639; openjdk-1.7.0.45.x86_64; Eclipse Kepler Java EE Release 1 build 20130919-0819
• Assignee: Unassigned
• Reporter: Dominik Jall
• Created: 09/May/14 09:41
• Updated: 09/May/14 09:41

Description

I am trying to do a search on a localized string. The strings are mapped by an ElementCollection of type Map. Key is a string interpreted as locale.

Here is the entity:

@Entity
@Table(name="category", schema="myschema")
@Access(AccessType.FIELD)
public class Category {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
Long id;

@ElementCollection(fetch=FetchType.EAGER)
Map<String, String> test = new HashMap<String, String>();

...
}

Here is the query:
String search = "%test%";
Locale locale = Locale.ENGLISH;
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<Category> criteria = cb.createQuery(Category.class);
Root<Category> category = criteria.from(Category.class);
criteria.select(category);
MapJoin<Category, String, String> tests = category.join(Category_.test);

Predicate searchClause = cb.and(
cb.equal(tests.key(), locale.toString()),
cb.like(tests.value(), search)
);

criteria.where(searchClause);
entityManager.createQuery(criteria).getResultList();

When the query is executed, I get this stack trace:

[err] java.lang.NullPointerException
[err] at org.apache.openjpa.jdbc.kernel.exps.PCPath.<init>(PCPath.java:105)
[err] at org.apache.openjpa.jdbc.kernel.exps.JDBCExpressionFactory.newPath(JDBCExpressionFactory.java:302)
[err] at org.apache.openjpa.persistence.criteria.Joins$MapKey.toValue(Joins.java:625)
[err] at org.apache.openjpa.persistence.criteria.Expressions.toValue(Expressions.java:66)
[err] at org.apache.openjpa.persistence.criteria.Expressions$Equal.toKernelExpression(Expressions.java:851)
[err] at org.apache.openjpa.persistence.criteria.PredicateImpl.toKernelExpression(PredicateImpl.java:171)
[err] at org.apache.openjpa.persistence.criteria.CriteriaExpressionBuilder.evalFilter(CriteriaExpressionBuilder.java:216)
[err] at org.apache.openjpa.persistence.criteria.CriteriaExpressionBuilder.getQueryExpressions(CriteriaExpressionBuilder.java:75)
[err] at org.apache.openjpa.persistence.criteria.CriteriaQueryImpl.getQueryExpressions(CriteriaQueryImpl.java:418)
[err] at org.apache.openjpa.persistence.criteria.CriteriaBuilderImpl.eval(CriteriaBuilderImpl.java:83)
[err] at org.apache.openjpa.kernel.ExpressionStoreQuery$DataStoreExecutor.<init>(ExpressionStoreQuery.java:763)
[err] at org.apache.openjpa.kernel.ExpressionStoreQuery.newDataStoreExecutor(ExpressionStoreQuery.java:179)
[err] at org.apache.openjpa.kernel.QueryImpl.createExecutor(QueryImpl.java:749)

I assume the key() function returns an invalid or non-existing path.
When I remove the key() part the query works.