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Posted to users@openjpa.apache.org by Lu Jiang <je...@gmail.com> on 2010/08/20 10:12:41 UTC
NullPointer Exception when using Case Expressions
Hi,all
I am experiencing the JPA 2.0 new features using openjpa 2.0,but
currently I was trapped.
I defined a entity class Student
@Entity
public class Student implements Serializable {
@Id
private Integer id;
...
private double totalScore;
private String rank;
//getters and setters
}
When I tried to simply update the rank,it all works fine.
public void updateRank(Integer id) {
String jpql="UPDATE Student s "
+ "SET s.rank= 'F' "
+ " WHERE s.id = " + id;
Query query = em.createQuery(jpql);
query.executeUpdate();
}
but when I tried to update the rank according to totalScore in the
following method.
public void updateRank(Integer id) {
String jpql = "UPDATE Student s "
+ "SET s.rank= "
+ " CASE WHEN s.totalScore<20 Then 'D' "
+ " WHEN s.totalScore>=20 AND s.totalScore<30 Then 'C' "
+ " WHEN s.totalScore>=30 AND s.totalScore<40 Then 'B' "
+ " WHEN s.totalScore>=40 AND s.totalScore<50 Then 'A' "
+ " Else 'N/A' "
+ " END "
+ " WHERE s.id = " + id;
Query query = em.createQuery(jpql);
query.executeUpdate();
}
Error like below will occur.
Exception in thread "main" <openjpa-2.0.0-r422266:935683 nonfatal user
error> org.apache.openjpa.persistence.ArgumentException: null
at org.apache.openjpa.kernel.QueryImpl.execute(QueryImpl.java:827)
at org.apache.openjpa.kernel.QueryImpl.updateAll(QueryImpl.java:898)
at org.apache.openjpa.kernel.QueryImpl.updateAll(QueryImpl.java:894)
at org.apache.openjpa.kernel.DelegatingQuery.updateAll(DelegatingQuery.java:582)
at org.apache.openjpa.persistence.QueryImpl.executeUpdate(QueryImpl.java:348)
at org.apache.geronimo.sample.jpa20.bean.Facade.updateRank(Facade.java:158)
at org.apahce.geronimo.sample.jpa20.test.updateRank.main(updateRank.java:20)
Caused by: java.lang.NullPointerException
at org.apache.openjpa.jdbc.kernel.exps.AndExpression.appendTo(AndExpression.java:68)
at org.apache.openjpa.jdbc.kernel.exps.WhenCondition.appendTo(WhenCondition.java:70)
at org.apache.openjpa.jdbc.kernel.exps.GeneralCaseExpression.appendTo(GeneralCaseExpression.java:114)
at org.apache.openjpa.jdbc.sql.DBDictionary.appendUpdates(DBDictionary.java:2127)
at org.apache.openjpa.jdbc.sql.DBDictionary.toBulkOperation(DBDictionary.java:2021)
at org.apache.openjpa.jdbc.sql.DBDictionary.toUpdate(DBDictionary.java:1933)
Does anyone have idea of this kind of issue?Or I got something wrong
with the jpql sentence?Hope someone can give me some clue:)Thanks in
advance!
Re: NullPointer Exception when using Case Expressions
Posted by Lu Jiang <je...@gmail.com>.
Hi Catalina
Thanks a lot for your sugguestion.
I tried to changed openjpa from 2.0.0 version to
2.1.0-snapshot.However ,the same exception occured.Actuall I don't
know why this happened..maybe I need more time to dig into it and find
the problem out.Anyway,thanks for your kind reply.
Re: NullPointer Exception when using Case Expressions
Posted by catalina wei <ca...@gmail.com>.
Hi Lu,
The trunk level code works fine, could you try OpenJPA SNAPSHOT version
2.1.0 ?
Here is SQL trace from running on DB2 using openjpa-2.1.0.SNAPSHOT:
10890 TRACE [main] openjpa.Query - Executing query: UPDATE Student2 s SET
s.rank= CASE WHEN s.totalScore<20 Then 'D' WHEN s.totalScore>=20 AND
s.totalScore<30 Then 'C' WHEN s.totalScore>=30 AND s.totalScore<40 Then
'B' WHEN s.totalScore>=40 AND s.totalScore<50 Then 'A' Else 'N/A' END
WHERE s.id = 10
10906 TRACE [main] openjpa.jdbc.SQL - <t 26780509, conn 12252334>
executing prepstmnt 31090792 UPDATE Student2 t0 SET t0.rank = CASE WHEN
t0.totalScore < CAST(? AS DOUBLE) THEN 'D' WHEN t0.totalScore >= CAST(? AS
DOUBLE) AND t0.totalScore < CAST(? AS DOUBLE) THEN 'C' WHEN t0.totalScore >=
CAST(? AS DOUBLE) AND t0.totalScore < CAST(? AS DOUBLE) THEN 'B' WHEN
t0.totalScore >= CAST(? AS DOUBLE) AND t0.totalScore < CAST(? AS DOUBLE)
THEN 'A' ELSE 'N/A' END WHERE (t0.id = CAST(? AS BIGINT)) [params=?, ?, ?,
?, ?, ?, ?, ?]
10906 TRACE [main] openjpa.jdbc.SQL - <t 26780509, conn 12252334> [0 ms]
spent
Catlaina
On Fri, Aug 20, 2010 at 1:12 AM, Lu Jiang <je...@gmail.com> wrote:
> Hi,all
> I am experiencing the JPA 2.0 new features using openjpa 2.0,but
> currently I was trapped.
> I defined a entity class Student
> @Entity
> public class Student implements Serializable {
> @Id
> private Integer id;
> ...
> private double totalScore;
> private String rank;
> //getters and setters
> }
> When I tried to simply update the rank,it all works fine.
> public void updateRank(Integer id) {
> String jpql="UPDATE Student s "
> + "SET s.rank= 'F' "
> + " WHERE s.id = " + id;
> Query query = em.createQuery(jpql);
> query.executeUpdate();
> }
>
> but when I tried to update the rank according to totalScore in the
> following method.
>
> public void updateRank(Integer id) {
> String jpql = "UPDATE Student s "
> + "SET s.rank= "
> + " CASE WHEN s.totalScore<20 Then 'D' "
> + " WHEN s.totalScore>=20 AND s.totalScore<30 Then 'C' "
> + " WHEN s.totalScore>=30 AND s.totalScore<40 Then 'B' "
> + " WHEN s.totalScore>=40 AND s.totalScore<50 Then 'A' "
> + " Else 'N/A' "
> + " END "
> + " WHERE s.id = " + id;
> Query query = em.createQuery(jpql);
> query.executeUpdate();
> }
>
> Error like below will occur.
> Exception in thread "main" <openjpa-2.0.0-r422266:935683 nonfatal user
> error> org.apache.openjpa.persistence.ArgumentException: null
> at org.apache.openjpa.kernel.QueryImpl.execute(QueryImpl.java:827)
> at org.apache.openjpa.kernel.QueryImpl.updateAll(QueryImpl.java:898)
> at org.apache.openjpa.kernel.QueryImpl.updateAll(QueryImpl.java:894)
> at
> org.apache.openjpa.kernel.DelegatingQuery.updateAll(DelegatingQuery.java:582)
> at
> org.apache.openjpa.persistence.QueryImpl.executeUpdate(QueryImpl.java:348)
> at
> org.apache.geronimo.sample.jpa20.bean.Facade.updateRank(Facade.java:158)
> at
> org.apahce.geronimo.sample.jpa20.test.updateRank.main(updateRank.java:20)
> Caused by: java.lang.NullPointerException
> at
> org.apache.openjpa.jdbc.kernel.exps.AndExpression.appendTo(AndExpression.java:68)
> at
> org.apache.openjpa.jdbc.kernel.exps.WhenCondition.appendTo(WhenCondition.java:70)
> at
> org.apache.openjpa.jdbc.kernel.exps.GeneralCaseExpression.appendTo(GeneralCaseExpression.java:114)
> at
> org.apache.openjpa.jdbc.sql.DBDictionary.appendUpdates(DBDictionary.java:2127)
> at
> org.apache.openjpa.jdbc.sql.DBDictionary.toBulkOperation(DBDictionary.java:2021)
> at
> org.apache.openjpa.jdbc.sql.DBDictionary.toUpdate(DBDictionary.java:1933)
>
> Does anyone have idea of this kind of issue?Or I got something wrong
> with the jpql sentence?Hope someone can give me some clue:)Thanks in
> advance!
>