RE: null scalary type in ScalarMap

• To: Curtis Rueden <curtis@xxxxxxxxxxxxx>, Bill Hibbard <billh@xxxxxxxxxxxxx>
• Subject: RE: null scalary type in ScalarMap
• From: "User" <xxxxxx@xxxxxxxx>
• Date: Thu, 17 Jul 2003 15:36:53 -0700

I'm constructing all my ScalarMaps internally through my own code I
added. In these loops, I extract the data types and set up the mappings
to DisplayRealTypes. I do this for every single input field that comes
in. That is why I have to create a "null" or "non-existent" mapping for
those that I don't want mapped. It's not as if the user can just not
select the fields that should not have a mapping because my iteration
automatically assigns something to every input field:


        // sets up ScalarMap[] array to pass into setMaps. sets up
mapping for each gene for cell at (i,j)
                public void setCellMapping(int width, int height) throws
VisADException, RemoteException {
                        
                        //System.out.println("In setCellMapping() and
width = " + width + "height = " + height);
                        int fields = theJgapAPI.field_count;  //limit on
for loop
                        int cellsAcross = mySS.NumVisX;   //3 for now
                        int cell_number = (width + (cellsAcross *
height));   //used as arg to getMappingForCell()
                        
                        ScalarMap[] theMaps = new ScalarMap[fields];
//array that will be passed into setMaps()      
                        
                        Data[] myData
mySS.DisplayCells[width][height].getData();  
                        Vector myVector = new Vector(fields); //capacity
= 10 because there are 10 input fields in small.v5d
                        int useless = DataUtility.getScalarTypes(myData,
myVector, false, true);  //will setup the myVector structure holding
input fields scalar types               
                        
                        for (int i = 0; i < fields; i++) {
                                //System.out.println("in
setCellMapping() and i = " + i);
                                
                                int assignment
theJgapAPI.getMappingForCell(cell_number, i);
                                DisplayRealType mapTo
mappings[assignment];
                                RealType mapFrom = (RealType)
myVector.get(i);                        
                                theMaps[i] = new ScalarMap(mapFrom,
mapTo);
                                //System.out.println("mapFrom = " +
mapFrom);
                                //System.out.println("mapTo = "+mapTo);
                                //String name = mapsFrom[i]; //string
name of input field i for this file, small.v5d for now
                                //RealType mapFrom
RealType.getRealType(name);  //constructs a RealType object from a given
String name             
                                //theMaps[i] = new ScalarMap(mapFrom,
mapTo);
                        }
        
mySS.DisplayCells[width][height].setMaps(theMaps);              
                }

If you know of a better way to do this, let me know.




-----Original Message-----
From: Curtis Rueden [mailto:curtis@xxxxxxxxxxxxx]
Sent: Thursday, July 17, 2003 3:25 PM
To: User
Subject: RE: null scalary type in ScalarMap


Hi,

If you don't want a particular ScalarType mapped to the display,
then don't create a ScalarMap for it! You should not create any
ScalarMaps with null DisplayRealType.

-Curtis

At 05:08 PM 7/17/2003, you wrote:
>Hi Curtis,
> 
>I'm actually trying to have null values for just the DisplayRealType
and
>not the ScalarType. I want the possibility for an input field to be
>mapped to a null value as one possible visualization instead of
*always*
>mapping every single input field in the data set to a VisAD parameter. 
>
>However, as I dig further and further into the original code, I'm
>finding that I would have to modify many classes to avoid null pointer
>exceptions. Am I correct that there would be no simple way to wrap a
>null DisplayRealType without getting null pointer exceptions?
>
>Thanks,

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    • From: Curtis Rueden