2.1.4 strange behaviour of a set.

trabajandob · **Posted:** Wed Jun 02, 2004 2:57 pm

I am experiencing some behaviour that to me looks to be a bug, but I just need quick affirmation to know whether I should post the code and mapping files.

I have an exact replica of the Parent/Child example in my code. I am in the *Parent* class attempting to to ascertain if the Parent contains the Child (Here TimeSheetItem is the Child, and TimeSheet is the Parent), before I try to delete it. I cant remember if the Parent/Child example is lazy load, but mine is, so keep that in mind.

Under any circumstances, (barring concurrent modifications; there is only one thread accessing this method, it cannot have anything to do with concurrency (from the perspective of my code at least)) Could the two print statements within the for loop print true, and the print statement which checks if the element is contained print false. This code is in the same method, and nothing is called, in between nor, are any other threads running. It would seem to me that the contains method might have a bug, I have overidden equals in my classes, but it would seem that by virtue of printing true above, the contains method should certainly return true, no _ ?

Code:

for (Iterator ir = getTimeSheetItems().iterator(); ir.hasNext(); ) {
   TimeSheetItem i = (TimeSheetItem) ir.next(); 

   System.out.println(tsi.equals(i)); 
   System.out.println(i.equals(tsi)); 
}
   
System.out.println(getTimeSheetItems().contains(tsi));

christian · **Posted:** Wed Jun 02, 2004 3:02 pm

What?

trabajandob · **Posted:** Wed Jun 02, 2004 3:25 pm

Okay, based on your response - I must not have been entirely clear what I was asking, or the situation I am in.

Code:

public boolean deleteTimeSheetItem(TimeSheetItem tsi)  
{
 boolean retval;
      
 for (Iterator ir = getTimeSheetItems().iterator(); ir.hasNext(); ) {
  TimeSheetItem i = (TimeSheetItem) ir.next(); 
  System.out.println(tsi.equals(i)); 
  System.out.println(i.equals(tsi)); 
 }
      
 try {
  if (getTimeSheetItems().contains(tsi)) {
   getTimeSheetItems().remove(tsi); 
   HibernateUtil.delete(tsi); 
   retval = true; 
 }
 else {
   retval = false; 
 }
}
catch (Exception he) {
 log.error("Unable to delete TimeSheetItem.", he);
   retval = false; 
 }
 return retval; 
}

This method is printing true twice above when it encounters the element that is *in* the list, however it is never returning true, from the call to contains. the getTimeSheetItems method is a simple return of the timeSheetItems Set. Here are the two mapping chunks (just the set parts)

In TimeSheet.hbm.xml

Code:

<set
            name="timeSheetItems"
            lazy="false"
            inverse="true"
            cascade="all"
            sort="unsorted"
        >
        <key
             column="timesheet_id"
         >
         </key>

              <one-to-many
                  class="com.sony.tsr.entities.TimeSheetItem"
              />
</set>

In TimeSheetItem.hbm.xml

Code:

<many-to-one
            name="timeSheet"
            class="com.sony.tsr.entities.TimeSheet"
            cascade="none"
            outer-join="auto"
            update="true"
            insert="true"
            access="property"
            column="timesheet_id"
            not-null="true"
        />

I hope this is clearer, maybe from the nature of your response, what I am witnessing is absurd, but I have stared at it for a while.

trabajandob · **Posted:** Wed Jun 02, 2004 3:49 pm

In looking for the problem I have variously tried different things; If I call:

Code:

try {
   HibernateUtil.currentSession().refresh(this);
} catch (HibernateException e) {
   e.printStackTrace();
}
 

In the method deleteTimeSheetItem(..) before the call to contains then it correctly deletes the TimeSheetItem. According to the semantics of Set, it would seem that by virtue of printing true from within the for loop, it should also return true from the contains call, but unless I call refresh before the call to contains, it does not return true. Is my logic flawed ?

jim

VampBoy · **Posted:** Mon Jul 12, 2004 1:43 pm

Don't know if you're still tracking this thread but I ran into the same exact problem.

I suspect your hashcode for the objects within the set is being modified in some way after the object is added.

The HashSet will key off of the hashcode of the object at the moment it is added to the Set. If you change the hashcode after this fact you will break the contains and remove.

intenter · **Joined:** Fri Aug 27, 2004 8:27 am **Posts:** 4

Hi.
I'm using Hibernate 2.1.4 and i have trouble with Set.
This is method, whitch calculates total price of an order:

Code:

    public double getTotal(){
        double total=0;
        Collection orderLines = this.getOrderLines();
        Iterator iter = orderLines.iterator();
        while (iter.hasNext()){
            double lineTotal = ((OrderLine)iter.next()).getTotal();
            total+=lineTotal;
        }
        return total;
    }

Some orders have several order lines, but orderLines.size() returns 1. Iterator finds only one element and this method returns price of one element only.
Here is mapping for Order object:

Code:

<hibernate-mapping>
    <class name="com.exshop.Order" table="exshop.ORDERS">

        <id name="id" type="integer" unsaved-value="0" >
            <column name="ID" sql-type="INTEGER" not-null="true"/>
            <generator class="increment"/>
        </id>

        <property name="date">
            <column name="Date" sql-type="DATE" not-null="true"/>
        </property>

        <many-to-one name="user" class="com.exshop.User" column="UserName" unique="true"/>

        <set name="orderLines" lazy="false">
            <key column="ORDER_ID"/>
            <one-to-many class="com.exshop.OrderLine"/>
        </set>

    </class>
</hibernate-mapping>

I have a queston:"Where are other order lines?". I am just a "new user", so, please, tell me what's wrong.
Thank you.