java.lang.UnsupportedOperationException: cannot perform look

gxtiger · **Joined:** Mon Mar 21, 2005 7:27 pm **Posts:** 2

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Hibernate version:hibernate-3.0rc1

Mapping documents:"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

Code between sessionFactory.openSession() and session.close():

Full stack trace of any exception that occurs:
java.lang.UnsupportedOperationException: cannot perform lookups on timestamps
at org.hibernate.type.TimestampType.getHashCode(TimestampType.java:99)
at org.hibernate.type.AbstractType.getHashCode(AbstractType.java:119)
at org.hibernate.type.ComponentType.getHashCode(ComponentType.java:162)
at org.hibernate.engine.EntityKey.getHashCode(EntityKey.java:68)
at org.hibernate.engine.EntityKey.<init>(EntityKey.java:41)
at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:136)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:107)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:184)
at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:173)
at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:69)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:429)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:424)
at com.bjrichtime.common.HotelLog.saveLog(HotelLog.java:73)
at com.bjrichtime.common.HotelLog.log(HotelLog.java:62)
at com.bjrichtime.common.HotelLog.log(HotelLog.java:67)
at com.bjrichtime.common.HotelLog.main(HotelLog.java:85)
Exception in thread "main"

Name and version of the database you are using:MySQl 4.018

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:

max · **Posted:** Tue Mar 29, 2005 10:44 am

read the stack trace.

paxsonyang · **Joined:** Fri Apr 22, 2005 4:33 am **Posts:** 9

Yes, I know what the exception is trying to say. The question is whether there is a way to make including a timestamp field in composite-id possible or not.

If it is possible, please tell me how to do it or refer me to the doc which describes it. Otherwise, just tell us that it is not possible to do it in Hibernate3 because I can do it in Hibernate2.

Thanks.

BTW, I know there is the implementation of TimestampType to not support performing lookups on timestamps by the following code segment,

Code:

public int getHashCode(Object x, EntityMode entityMode) {
    throw new UnsupportedOperationException("cannot perform lookups on timestamps");
}

paxsonyang · **Joined:** Fri Apr 22, 2005 4:33 am **Posts:** 9

Actually, it is not possible to include a field with "timestamp" type in your composite-id because the TimestampType did not support it by nature(it did not support the getHashCode method) and it should not support it due to the different timestamp handling mechanisms by database vendors.

However, I resolve this issue by changing the type from "timestamp" to "calendar" in my Hibernate's mapping files which means that I also have to change the type from "java.util.Date" to "java.util.Calendar" in my POJOs.

--------------------------------------- MAPPING FILES

Code:

    <property
        name="approveDate"
        type="date"
        column="APRV_DT"
        not-null="true"
        >
    </property>

to

Code:

    <property
        name="approveDate"
        type="calendar"
        column="APRV_DT"
        not-null="true"
        >
    </property>

--------------------------------------- POJOS

Code:

private Date _approveDate;

to

Code:

private Calendar _approveDate;

I verified it by running my testcases passed. I hope it is helpful to you because I also encountered this issue and took a while to figure it out.

paxsonyang · **Joined:** Fri Apr 22, 2005 4:33 am **Posts:** 9

http://forum.hibernate.org/viewtopic.php?t=940213

mortensi · **Joined:** Thu Apr 21, 2005 12:20 pm **Posts:** 4

Quote:

[I verified it by running my testcases passed. I hope it is helpful to you because I also encountered this issue and took a while to figure it out.

Thanks a lot, it solved my problem.

Morten Simonsen