ClassCastException: java.math.BigDecimal

By: Yong Wang - wymz
ClassCastException: java.math.BigDecimal
2002-11-19 14:48
Hi I am getting this cast exception at runtime:

Caught exception: Error evaluating expression estimated value : variable_StatusGroup_TOTAL
java.lang.ClassCastException: java.math.BigDecimal at jsinventory2grp.evaluateEstimated(jsinventory2grp.java:552) at dori.jasper.engine.fill.JRCalculator.evaluateEstimated(JRCalculator.java:633) at dori.jasper.engine.fill.JRCalculator.estimateVariables(JRCalculator.java
...
here is the related portion of my jasper XML:
...
<field name="wholesale_price" class="java.lang.Double"/>
...
<variable name="StatusGroup_TOTAL" resetType="Group" resetGroup="StatusGroup" c
lass="java.lang.Double" calculation="Sum">
<variableExpression>$F{wholesale_price}</variableExpression>
</variable>
...

I would appreciate if someone can tell me what I am doing wrong. thanks.



By: Yong Wang - wymz
RE: ClassCastException: java.math.BigDecimal
2002-11-20 07:21
Thanks steve. You are right on the target. I didn't realize MySQL's decimal(10,2) gets translated into BigDecimal.


By: Steven Blough - stevenblough
RE: ClassCastException: java.math.BigDecimal
2002-11-20 04:23
Confirm that the field type coming from the database is a Double. By the error you are receiving I would guess that the database field is being returned as a BigDecimal not a Double. If you change the class types in your xml to BigDecimal that problem should be resolved.

Good Luck

Steven Blough



By: Yong Wang - wymz
RE: ClassCastException: java.math.BigDecimal
2002-11-20 13:04
This BigDecimal is still haunting me. I have a field "balance" defined as decimal( 10, 2) but I also have some SQL redefine "balance" at the selection as follows:

select if(isnull(balance), 0.00, balance) as balance ...

so what's happening now is the object in result set becomes Double.

I have to use Double as follows:

<field name="balance" class="java.lang.Double"/>
...
<variable name="InventoryGroup_balance" resetType="Group" resetGroup="Inventory
Group" class="java.lang.Double" calculation="Sum">
...
<textFieldExpression class="java.lang.Double">
$V{InventoryGroup_balance}
</textFieldExpression>
</textField>
...
<textFieldExpression class="java.lang.Double">$F{balance}</textFieldExpression>
...

at runtime, I am again getting cast exception:

Caught exception: Error evaluating expression value : variable_balance
java.lang.ClassCastException: java.lang.Double
at custlist.evaluate(custlist.java:332)
at dori.jasper.engine.fill.JRCalculator.evaluate(JRCalculator.java:656)
...

I tried to switch to BigDecimal, still getting cast exception (at different location?):

Caught exception: Error evaluating expression value : variable_balance
java.lang.ClassCastException: java.lang.Double
at custlist.evaluate(custlist.java:367)
at dori.jasper.engine.fill.JRCalculator.evaluate(JRCalculator.java:656)

How do I get around this problem? where is the file "custlist.java"? thanks.



By: Teodor Danciu - teodord
RE: ClassCastException: java.math.BigDecimal
2002-11-23 02:35

Hi,

You probably have to cast the 0.00 value
to decimal(10, 2) in your SQL query.

I hope this helps.
Teodor



By: Yong Wang - wymz
RE: ClassCastException: java.math.BigDecimal
2002-11-20 14:11
This same problematic jasper XML works fine with embedded query and a database connection, but doesn't work with custom datasource. All this custom datasource (implements JRDataSource) does is use the same query string to get a ResultSet and return an object value from the current row for the JRField.

Another observation is embedded query and a database connection works even when jasper type doesn't match database type:

for example, I have "YEAR" defined as INT in database, but defined as "java.lang.String" in jasper, and it still works w/o exception. I suspect some data conversion is done in jasper for this case.

I would appreciate if someone could shed some light on my type cast problem. Thanks.


By: Yong Wang - wymz
RE: ClassCastException: java.math.BigDecimal
2002-11-21 10:00
Another observation is if the field does not involve in the variable calculation, the conversion from BigDecimal to Double is automatic, no exception.
I really need some help with the problem I posted at 2002-11-20 16:04. Thanks!


By: Yong Wang - wymz
RE: ClassCastException: java.math.BigDecimal
2002-11-21 11:17
I have figured out my problem. But I am still unclear about the following two items:

1) the different behavior btw custom datasource and embedded sql with a connection. The field type is much relaxed in the latter.

2) with custom datasource, those fields involved in variable calculation must have exact java type as returned by datasource while no such requirement for other fields.



By: Teodor Danciu - teodord
RE: ClassCastException: java.math.BigDecimal
2002-11-23 02:31

Hi,

Why don't you just take a look at the source code
of the JRResultSetDataSource class to see why
it works and your implementation does not?

I hope this helps.
Teodor