ArcGIS Engine Developer Guide

JAVA APPLICATION PROGRAMMING INTERFACE
System.out.println(" wksp is a RasterWorkspace");
rasWksp = (RasterWorkspace)wksp;
}
else{
try{
rasWksp = (RasterWorkspace)wksp;
rasWksp.openRasterDataset( aRaster );
}
}catch(Exception e){
/* Code executes if wksp is not a RasterWorkspace. */
System.out.println(" wksp is not a RasterWorkspace");
}
Methods that take out parameters
ArcObjects provides many methods that return more than one value. The ArcGIS
API for Java requires sending single element arrays as parameters to such methods.
Basically, you pass in single element arrays of the object that you want to be
returned, and ArcObjects fills in the first elements of those arrays with the return
value. Upon returning from the method call, the first element of the array contains
the value that has been set during the method call. One such method that
you will be using in this section is the toMapPoint of IARMap interface. Take a
look at the javadoc of this method:
public void toMapPoint(int x,
int y,
double[] xCoord,
double[] yCoord)
throws IOException,
AutomationException
Converts a point in device coordinates (typically pixels) to coordinates in
map units.
Converts the x and y screen coordinates supplied in pixels to x and y map
coordinates. The returned map coordinates will be in MapUnits.
Parameters:
x - The x (in)
y - The y (in)
xCoord - The xCoord (in/out: use single element array)
yCoord - The yCoord (in/out: use single element array)
Notice that the parameters xCoord and yCoord are marked as “in/out: use single
element array”. To use this method, the first two parameters are the x and y
coordinates in pixel units. The next two parameters are actually used to get return
values from the method call. You pass in single-dimensional single element double
arrays:
double [] dXcoord = {0.0};
double [] dYcoord = {0.0};
When the method call completes, you can query the values of dXcoord[0] and
dYcoord[0]. These values will be modified by the method and will actually refer to
the x and y coordinates in map units. A practical example of this method call is
192 • ArcGIS Engine Developer Guide