Question

I am current porting some legacy code over to using JPA and have run into an issue trying to simplify one of the tables into an entity.

I have a table of various readings taken throughout a 24hr period – every half-hour.
It looks like:

Date     |R1|R2|R3...R48

1/1/2012,1,5,1,3,3,4,5,5....etc

I’d like my entity bean to look something like:

@Entity
public class Reading {

    @Id
    String date;

    @??
    int[] values;

    @???
    int sumOfValues
}

Any suggestions how I could approach this? Is it even possible? Also – I only want to read these values, if that make it any easier.
I’m using EclipseLink 2.4 with MongoDB

** UPDATE **

Almost have it – but need to maintain order somehow (I think the fields are mapped out of order) – or pass through a reference to the column name:

@Entity  
@Customizer (RawDataCustomizer.class)  
public class Reading {  
private List<Integer> values...  
public void setValue(Integer value)...  
public static class RawDataCustomizer implements DescriptorCustomizer {  

    @Override  
    public void customize(ClassDescriptor descriptor) throws Exception {  
    //loses ordering?  
    for (int i=1; i<=48; i++)  
    descriptor.addDirectMapping("R"+i, "getValue", "setValue", "r"+i);  

}  

Answer 1

Final solution, using @Customizer – not ideal at all – but works well enough for now:

public static class RawDataMapping extends EISDirectMapping  {
    private final int index;
    public RawDataMapping(int index, String attributeName,String fieldName) {
        super();
        this.index = index;
        setAttributeName(attributeName);
        setFieldName(fieldName);
        setAttributeAccessor(new CustomAccessorAttributeAccessor(this));
    }
    public void set(Object object, Object value)...
    public Object get(Object object)...
}