ArcGIS Engine Developer Guide

JAVA APPLICATION PROGRAMMING INTERFACE
to update the status bar with the current map coordinates as the mouse moves
over the control.
public void updateStatusBar(
IARControlEventsOnMouseMoveEvent params,
IARControl arControl,
JLabel statusLabel) throws IOException {
/*
* Create two single-dimension arrays of type double to serve as
* "out" parameters in a call to toMapPoint.
*/
double[] dXcoord = {0.0};
double[] dYcoord = {0.0};
int screenX = params.getX();
int screenY = params.getY();
IARMap arMap = arControl.getARPageLayout().getFocusARMap();
arMap.toMapPoint(screenX, screenY, dXcoord, dYcoord);
statusLabel.setText("Map x,y: " + dXcoord[0] + ", " + dYcoord[0]);
}
The ArcGIS API for Java will not allow developers to populate an array with a
superclass type, even when it has been cast to a superclass type. Consider the
following Java example:
Integer[] integers = { new Integer(0), new Integer(1), new Integer(2)};
Object[] integersAsObjects = (Object[])integers;
integersAsObjects[0] = new Object();
The above is not allowed and will cause an ArrayStoreException. Consider the
following ArcObjects example:
Polyline[] polyline = {new Polyline()};
tin.interpolateShape( breakline, polyline, null );
Polyline firstPolyLine = polyline[0];
The above is not allowed and will cause the same ArrayStoreException as the
earlier example. Take a look at the interpolateShape method of ISurface and analyze
what is going on here.
public void interpolateShape(IGeometry pShape,
IGeometry[] ppOutShape,
Object pStepSize)
throws IOException,
AutomationException
Parameters:
pShape - A reference to a com.esri.arcgis.geometry.IGeometry (in)
ppOutShape - A reference to a com.esri.arcgis.geometry.IGeometry
(out: use single element array)
pStepSize - A Variant (in, optional, pass null if not required)
Throws:
IOException - If there are communications problems.
AutomationException - If the remote server throws an exception.
IGeometry is a superinterface to IPolyline, and the Polyline class implements both
interfaces. In the first attempt you tried to send a single element Polyline array into
a method that requires an in/out IGeometry parameter. This causes an
Chapter 4 • Developer environments • 193